For those of you who really don’t understand what your talking about when it comes to designing a link type suspension let me fill you in on a lot of stuff. First when designing a link type suspension for off-road use you must consider: Anti-Squat, Roll axis, Link length, and Link angle.
Anti-Squat is a property that determiners how much the rear will raise or lower when accelerating. This is the reason a mildly modified Wrangler with leaf springs climbed the (A-7) obsticle that the Scorpion could not at the last ARCA event in Cedar city. With a large percentage of Anti-Squat the rear end of the vehicle will lift under acceleration. In the case of the Scorpion this causes the rear end to try to drive forward under the vehicle while the vehicle remains still. The result is the vehicle develops a condition similar to axle-wrap. The rear end starts to hop causing a decrease in traction.

Link angle is directly correlated to Anti-Squat characteristics. The steeper the angle of the links (assuming they are parallel) the greater the Anti-Squat. There are ways to combat this.

A longer Link length doesn’t necessarily mean a less steep angle. Also a longer link doesn’t always mean less rear steer. Rear steer is a property that is determined by roll-axis. Many of you are not even considering this when talking about link design. This is one of the most important considerations. Also when making links longer there are considerations such as bending moments, Euler’s Coulomb Buckling Theory, and break over angle (High Centering).

Many of you have commented on how a link type rear is not good since it reduces the amount of front flex by making the rear flex more. This is not true. If the suspension is properly set up the amount of flex for both axles will remain the same.

Before talking about or building a link type suspension, figure out what you need to know, or ask someone who does. It will make you look a lot smarter and you will be much happier with the results.

Now let the smack talkin begin !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!


<IMG SRC="smilies/tongue.gif" border="0">

I would think on a rockcrawling rig one would want very little anti-squat. Correct me if I'm Wrong but in a link type suspension the amount of anti-squat is detirmined by the angle of the links ie more angle more resistance to squat so to speak. any opionions All Mighty God of Suspension?

FYI - I have no clue who you are, what you just posted could have easily been cut & pasted from any suspension design manual, and what you just posted is not very impressive either (and I don't even know that much about link suspensions).

On the whole - I haven't seen anything here that makes you look like some suspension "god", so if you plan to post to impress - pull out the bigger guns <IMG SRC="smilies/rolleyes.gif" border="0">

(pic's at the bottom)

apparently your opinion of a god is lower than mine.

i have a well balanced rig front to rear, it has a rear 1/4 elliptic 4 link and also a front 5 link. so yes a link type susp. can be well balanced.

i know where my CG. is, i know the height of my roll center, my anti-squat is dead on with the weight, wheel base, and center of gravity, i have less than 2 inches of rear steer at full droop measured on the vertical plane.

so i'm very happy with it.

i don't think your going to tell me anything that i haven't already forgotten.

at least i havent seen anything that you have posted that has impressed me yet, but please keep trying.

and i'm nowere near a god at anything.
steelman


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I think anti-squat is GOOD when run with a center limiting strap.

<STRONG>I would think on a rockcrawling rig one would want very little anti-squat.</STRONG>
Depends... you going uphill or downhill?

There's no single answer to all of these things, and they interrelate with complexity. I've seen video of a high-travel rig travel into apparent squat on one side of the flexed-out rear suspension, and anti-squat on the other side. Every time he fanned the gas, the whole rig wanted to roll itself. Ooops!

Experimentation is fun, but most home-brewed multi-link suspensions don't seem to have solutions that allow safe on-road handling... they make too many compromises in favor of off-road performance.

Randii

Calpoly..

You have stated some good points on
Design principals, but nothing that you couldn't find at local book store...

To truely become a "GOD" you must be able to turn "Principals" into reality...SO just how many linked rigs have you made? and please post pics...

Please understand that going to school and the real world are different...

I speak from exp. former "ASU GUY"

Originally posted by Tin Bender:
<STRONG>

I speak from exp. former "ASU GUY"</STRONG>

Damn i almost went there, thank god i did not <IMG SRC="smilies/biggrin.gif" border="0">

And if CALPOLYPUD=BRIAN then <IMG SRC="smilies/thefinger.gif" border="0"> <IMG SRC="smilies/skull.gif" border="0">

lemme guess WEll Done Man Chico?..

actualyl he is a drop out, local jc student turned sequoia now computer dork/mechanic to all friends! he he, jiMMy

A little Anti-Squat is good because it increases the force placed on the tire. This is createtd by a link setup in which the vector sum of the forces in the verticle plane are pointed toward the ground. In the case of two parrallel links parallel with the ground, when the vehichle is at ride hight there is no anti-squat caused by the links. Intertia of the center of gravity will actually cause the rear to squat in this particular case, as the vehicle accelerates. Of course this is only true if the center of gravity (CG from now on)is above the roll ceter of the vehichle. On almost all offroad vehichles the CG will be higher than the roll center. So what we really want is a susupension that combats the squat caused by acceleration and provides a small amount of downward force to increase grip. On vehicles with large link angles in the rear the anti squat will be very high. What this means to rock crawlers is get your links as flat as possible. This is my general reccomendation although there are ways to run larger angles and still accomplish the same task.

For Dr.Mud If you believe that this is a cut and paste ask me a more general question and you will see where the knowledge is coming from! The Big Guns are Drawn!!!!!!!!!!!!!!

Steelman, Your Bronco does appear to be well balanced and the rear suspension does have very little rear steer. I see a little more in the front though. Your getting close! The front does not matter as much though because you can combat the link sterring effect with the steering wheel. The only real problem is the fender rub cause by this.

Ant, the center limiting strap only limits how far the rear axle will move it has nothing to do with anti-squat.

randii, You are correct, very little anti-squat is desireable. In either case up or downhill you do not want much. In the case of downhill it is not such an issue since forward acceleration is what cause anti-squat. In most cases you are decelerating and this would actually lend to squating in the rear. This is good because it combats the tendency for the vehichle roll forward which is caused by the center of gravity being higher than the roll center.

Keep the questions coming! The better we design our suspensions the more extreme the crawling!

Tin Bender, I know the pricipals i have stated you could find anywhere if you look. I am trying to remain in a Laymen's point of view so that everyone who reads can understand. If you want a more detailed response let me know. I understand that going to school and the real world are different. I am one of those people who believe you must build your ideas and see how well they work in the real world. Many people can spit out ideas and not have any sense of how to apply them. Should have went to Cal Poly so you actually had to build what you learned. By the way my name is not Brian!

Jimmy76FJ40, Just weld it and let it be! You don't have to worry about the airlines any more.

I am building a 63FJ40 sort of. When it is all done I don't know how much toyota will be left. But as the suspension progresses I will post pics. Does anyone need a set of high steer arms for a Dana44? I am thinking of making a few sets. Let me know!

here's my problem.....
I work at the China Lake Naval Weapons Center, and I am surrounded by guys who have more deg. than you can count on both hands...
Yes, they are some VERY BOOK smart guys, but when it comes right down to it, they couldn't biuld a Snap-tight model...

True story: A guy with 6 engineering degrees asks me to the parking lot to show him how to change his wiper blades..NO SHIT!!!!

Yeah, Looking back I wish I would have gone to CalPoly... I have a beach house in Morro and the "hands on "is the thing I missed most..
If you are infact putting the principals to work than I'll step back and say get it!!

Next time I'm in town, I'll buy the <IMG SRC="smilies/beer.gif" border="0"> and we can "talk shop" <IMG SRC="smilies/biggrin.gif" border="0">

How does this sound, and what are the problems, and what would be better...

Rear mounts on the axle like front Ford C bushings - one per side. 2 links (one per side) from the C bushings in towards the center of the vehicle to a trailer stub axle pivot on a crossmember directly under the rear output yoke of the Tcase. The stub axle allows full 360 degree rotation, and a spring eye type poly bushing there allows for pivoting off of that s well. Both links will be attacked together at this pivot - basically a "V" with the point at the Tcase and the legs at the axle.
Springs will be handled by stock leaves, but with a shackle at both ends.
You are looking at a link length of roughly 38".

1. Will this work, or will the single pair of links (V link) cause the rear of the vehicle to raise up when you take off?
2. Will a panhard bar be necessary to control side-to-side movement of the axle when on the road/trail?
3. If this will not work, could the lower links ditch the C bushing type design for a spring eye poly mount and add a set of long upper links parallel with the leaf springs and control axle side-to-side movement as well as eliminate the rear of the vehicle wanting to raise up (is that what you mean by "anti squat"?)

[ 07-17-2001: Message edited by: DR. Mud ]

This thread has to be a joke right? Come on stud you can't be serious about yourself can you?

randii, you are correct
So where's my cookie? <IMG SRC="smilies/biggrin.gif" border="0">

Randii

Depends on where you’re wheeling. Rubicon anti squat doesn’t hurt so much. Moab it is your worst enemy.

Questions for the god.
What effect does the mounting point locations on the frame have on anti squat?
What effect does the mounting point locations on the axle have on anti squat?
And why?

1. Will this work, or will the single pair of links (V link) cause the rear of the vehicle to raise up when you take off? Yes
2. Will a panhard bar be necessary to control side-to-side movement of the axle when on the road/trail? Yes

advice, dont go there.

Best link related math tip I can offer...
A 3/4" hiem joint will thread into a 1/2" pipe female fitting.
Some used pipe and some hiems answers alot of clearence questions cheaply.

Originally posted by Air Bag:
<STRONG>advice, dont go there.</STRONG>

Wow - now do you intend to explain your answers or are you just claiming un-questionable expertise like stud man up there? <IMG SRC="smilies/wink.gif" border="0">

I agree that a degree doesn't give you the ability to become a god. I will have my Mechanical Engineering degree this December. I took a vehicle dynamics class last year that helped me understand some more about my CJ, but it doesn't make up for real world experience. We get our hands on training by building a mini-baja car. Full suspension go cart. You are actually tested at a competition. This is where you either put up or shut up. Most schools just put up and are satisfied with mediorocricy(sp). We, on the other hand went out to do our best design ever. It showed when we won one event and took fourth in another. With two cars, we finished 6th and 13th out of about 120 schools. That is hands on training.

So don't go spouting off your mouth about you knowing everything about link suspensions. Even what you think will work in your head or on the computer won't even come close to working. More times than not, it will end up binding and breaking things. The guys on here can build some of the most awesome link suspensions I have ever seen. If you want to learn something, ask questions from these guys and trade ideas. Don't think that your knowledge is soooo much greater than everyone elses. So back the fawk up and let everyone share their opinions and ideas. <IMG SRC="smilies/flipoff.gif" border="0"> You're not always going to be right.

Erin

Originally posted by willymutt:
<STRONG> You're not always going to be right.</STRONG>

Of coruse he isn't - I am the official "Know-It-All" of this BBS and everyone knows it <IMG SRC="smilies/tongue.gif" border="0">

Dayyyyyyyummmmmmmmm Erin....
Smack'n like a pro!!!!! <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

Rapid city!!!! NO shit?? Hows life in the Big City?? I was Born in Rapid..... Still have Family in Custer <IMG SRC="smilies/biggrin.gif" border="0">

I am not impressed - I have seen no pics yet..

Yes, principles and application are 2 different things..

- another engineer..

Tin Bender - When you going to get that rig up here and do some wheelin? We could show you a thing or two!

I just hate to see people who think they know everything try and tell people how to do something. That is the greatest part about our sport is the experimentation. If you build it and it doesn't work, it's just a couple short steps to the torch to start over.

Erin

I think I'll break from tradition and say I am glad to see this stuff on the board. Pics would be nice, but I'd like to hear more! I'd like an explanation for something you would set up, in layman's terms of course. I'm just running a wishbone 3 link and I'll be the first to say it isn't the most popular street rig. I wouldn't mind learning how to make it perform better on road as well as off road. I'd like to get the rear as good as possible before I start on the front. So any advice or ideas are always welcomed in my corner!

Originally posted by willymutt:
<STRONG>We get our hands on training by building a mini-baja car. Full suspension go cart. It showed when we won one event and took fourth in another. With two cars, we finished 6th and 13th out of about 120 schools. That is hands on training.
</STRONG>

I hadn't heard how the SD Mines car did in competition.. nice to hear it did so well!

My buddy David was on the team last year (yet another IH-freak)

How often do you guys get to go wheelin'? Rapid is a bit of a haul from Helena, but I have a trailer n' tow rig now..

Tin Bender, I know what you are talking about, I used to work at a lot of Automotive parts stores and you wouldn't believe how many people have no idea how to change a wiper blade. I run the Senior project Lab machine shop at Cal Poly and even at this school with so much emphasis on learn by doing there are lots of "Book Smart Geniuses" who have no idea how to build anything. Some couldn't use a drill press if you set everything up for them.

Bender where do you live? I may be heading up to the central valley soon if you are from there i'll stop by. I need to pick up some roll cage materials in the area and a 22re for my 4runner. Me and a freind are going to build a supercharged 22re cause the runner just doesn't have enough juice. So many projects so little time.

Dr.Mud, If I am understading you correctly, you're idea is to make a crude fourlink set-up using leaf springs and a v-link/a-arm. If this is correct the only benifit I see is that you will control axle wrap. If you flip your idea around and place the pivot on top of the pumpkin and the two upper links to the frame it will not only control axle-wrap but side to side movement as well. The raising of the rear of your vehichle (anti-squat)is determined by the link angles and link length. With the setup you are talking about it seems that there would be minimal anti-squat because the leaf springs run parralell to the ground. Your rear steer characteristics would also be very good because the roll axis is realatively flat. In your comment about adding another set of links you are almost to the point of a 1/4 eliptic setup. The main problem I see with this design is that if it is not setup properly the suspension will bind in down travel causing you to have even less that before. If your frame mounts for the v-link/a-arm are the same length as the distance from the front spring eye to the axle housing binding should not be a problem. Let me know if this makes sence!

Fearme, I put the God thing up to get people to read! Looks like it worked. I just wanted to start an important discusion where some engineering was involved not just ideas about what a friend told another friend what he thought would work. The more people who know the better the new ideas are.

Randii, how about a brownie point?

AirBag, You are correct! Anti-squat is a big killer when it comes to climbing steep angles. On flat crawling i.e. Rubicon, The anti-squat doesn't hurt you as much. The mounting points on the frame and axle don't have as much to do with anti-squat as the angle of the link and the link length. Anti-Squat is caused be the vector sum of the forces in the verticle direction. Verticle force vectors become larger when the link angle is increased. If you know any Geometry the verticle component of the resulting force caused by the axle pushing on the link will be directed down. This causes the link to push the rear of the vehichle up. If your lower link has a steep angle then an upper link with an angle exactly the same with a slope up toward the rear of the vehichle instead of the front like the lower links will have exactly the opposite verticle force component. What all this mean is that if your links are crossed like an X from the side profile your anti-sqaut should not be apperant. Another way to accomplish the same results is to have both links as parrallel to the ground as possible. Of course this changes your roll axis which causes rear steer. So there is no perfect solution only an iterative process of finding the least amount of unwanted properties.

Mounting point locations have a lot to do with roll axis. But another consideration is the angle of the link as you look at them from a top view. These are the determining factors of the roll axis.

willymutt, Before you go talking about what your school did with mini baja. You should tell everyone that the mini Baja is a competition based on many things such as Design, Sales, Marketability, Acceleration, Braking, Hill Climb, and endurance. Almost none of these have to do with rock crawling. I know I helped build the mini baja for our school also (Kansas Was Fun). Suspension design for mini baja is much different than a rock crawling suspension. Besides in mini baja the most important consisderations are light weight, and strength. Not suspension design. I saw a Piece of sh@t design from RIT with no suspension do very well! I do agree there are many people who have very nice suspension around and I am not disputing that. I am just here talking about technical issues.

I try to go wheelin a lot, but my CJ has been out a commision for awhile now. Just got it running. Hope to go the next couple weekends.

Erin

I too work with Engineer's who spent way to long in school to understand the simple things in life, like remembering to put on pants before coming to work....sounds simple enuff but I can't count the numbers of times he showed up without them.....I'm with the rest put up or shut up!!! If you were that good Hendricks is always looking for the best!

Just to add a little more. To prove that what looks good on paper doesn't always work, the team that won the design part of the baja competition did terrible in the actual driving parts. On the other hand, ours with 4-wheel steer that everyone thought wouldn't work, kicked ass.

Erin

Originally posted by calpolystud:
<STRONG>
Ant, the center limiting strap only limits how far the rear axle will move it has nothing to do with anti-squat.
</STRONG>

You wanna bet $$ on that?? Come tell that to my rig, It does not agree with you on that one!! And I never said the strap had anything to do with anti-squat, only an idiot would think that.
<IMG SRC="smilies/rolleyes.gif" border="0">

[ 07-17-2001: Message edited by: Ant ]

willymutt, I was talking to your team leader or mabe your advisor, "the Girl", at the awards banquet in Manhattan, very smart girl. I give you guys credit for the four wheel steering. It was a nice touch. I don't believe it was neccisary (too much weight) but i bet it scored brownie points with the judges. Wait till you see our next car! See you in El Paso!

Ant,
You are putting a band-aid on a gun shot wound. With proper design a limiting strap wouldn't be needed. But if you have fun in your rig thats all that count right?

Originally posted by calpolystud:
Dr.Mud, If I am understading you correctly, you're idea is to make a crude fourlink set-up using leaf springs and a v-link/a-arm.

Actually, it would be a 2 link - what makes it "crude"?

If this is correct the only benifit I see is that you will control axle wrap.

Tons of articulated travel is not another benefit? it seems that way to me...

If you flip your idea around and place the pivot on top of the pumpkin and the two upper links to the frame it will not only control axle-wrap but side to side movement as well.

Yes, this would be a "standard" 4 link... I could do that as well...

The raising of the rear of your vehichle (anti-squat)is determined by the link angles and link length. With the setup you are talking about it seems that there would be minimal anti-squat because the leaf springs run parralell to the ground. Your rear steer characteristics would also be very good because the roll axis is realatively flat.

Ok... I can buy that too...


In your comment about adding another set of links you are almost to the point of a 1/4 eliptic setup.

Wait a sec...
"1/4 Eliptical" has nothing to do with the link design - as with a 4 link coils, coilovers, 1/4 eliptical, or leaf springs with shackles at both ensd are merely the method for suspending the vehicle, where the 4 link (or V link, etc.) is the method for axle location.

The main problem I see with this design is that if it is not setup properly the suspension will bind in down travel causing you to have even less that before.

How so?

The benefit of the V link as I described originally is the allowable 360 degree's of non-binding rotation - which translates into ZERO binding during travel (taking the suspension method out of the picturte of course). That being said, the method you use to suspend the vehicle is where you would be introducing any of the limits for articulated travel.
Springs with shackles at both ends are actualy a pretty good way to get plenty of suspension travel for cheap, without having to re-configure the sporing rate like when you cut a pack in haf for use in 1/4 eliptical.

If your frame mounts for the v-link/a-arm are the same length as the distance from the front spring eye to the axle housing binding should not be a problem. Let me know if this makes sence!

Again, with a shackle at each end of the spring, you can run a longer V link (or 4 link for that metter) than the front half of the leaf spring and the shackle onthe front of the spring allows for VERY little binding...


Anyway, this is hard to describe with words... maybe I could draw ( <IMG SRC="smilies/puke.gif" border="0"> ) a picture <IMG SRC="smilies/tongue.gif" border="0">

My main worries with the V link would be side-to-side movement of the axle and whther or not the leaf springs and shackles would provide enough lateral support for use, or whether a panhard bar would be required.

Also, the ide of the C bushing type mounts at the axle would be like a huge torque bar and want to lift the vehicle up where the link attaches to the frame in the center of the vehicle.... From what I understand, the shaggered mounting location of frame mounts for 4 links are how the rotational force of the axle housing is not transmitted to the frame - is this correct?

calpolystud - You might be surprised to learn that the people who designed our mini-baja car are guys who like to rock crawl more than anything. We have rock crawlers, not prerunners, which is basically what you design for the competition. I am not trying to say the mini-baja is like rock crawling, but design principals go into it just like our rigs. There are some simularities to some vehicles. Trying to get low horsepower to produce a fast rig. Just like trying to make a 4 cyl work for rockcrawling. Lots of challenges.

As far as our car not needing four-wheeling steering, it did. We were forced to use the frame from our previous years car. That made the car exactly 96" long. This also made it very slow and cumbersome going around corners. The 4-wheel steer helped out tremendously. And as far as adding weight. It was actually lighter than the previous year with the same frame. It also didn't seem to matter on the hill climb.

The girl you talked to had no clue on how our car worked. She is one of those people who is very book smart, but couldn't tell you why our car had bump steer in the rear, or why we did many of the things we did. She was a major pain in the ass the whole time she was there. Damn Grad Students!

I have one question for you. How much money did you guys spend on your car? Just trying to get a comparison to what we spent.

Erin

[ 07-17-2001: Message edited by: willymutt ]

Originally posted by calpolystud:
<STRONG>Ant,
You are putting a band-aid on a gun shot wound. With proper design a limiting strap wouldn't be needed. But if you have fun in your rig thats all that count right?</STRONG>
Scuse me?? You can read all the books you want and none will tell you how to build proper "Rock Crawling" 4-link suspension all your books are based on drag racing circle track and baja racing. I feel extra anti-squat is good and I just added the limit strap to keep the axle from trying to walk under the rig, the design was intentional. A lot of people on this thread seem to have actual experience building and using link suspension, do you??? And why don't you tell every baja racer that they "band-aided" their suspension, cause last time I looked every truck in the Baja 1000 was running limit straps!!!
<IMG SRC="smilies/laughing.gif" border="0">

[ 07-17-2001: Message edited by: Ant ]

Originally posted by Tin Bender:
<STRONG>lemme guess WEll Done Man Chico?..</STRONG>

Little bit of it all, and yes Jimmy i finished <IMG SRC="smilies/tongue.gif" border="0">.

i did Onlone, and San Fran

Jason Paule is building a suspension right now with the top link mount above the pumpkin a ways. This is to induce anti-squat. They claim this will make the tire create more pressure on the rock. He said the Currie Fire Ant does this. It makes sense. I am interested in seeing if it works.

Erin

Dr.Mud
It is a four link becuse if I understand you correctly your leafs will still be attached to the axle and therefore are a link. Are you planning on decreasing the spring rate because the only way your are going to get "tons" more articulation is to decrease the spring rate. You will gain some frome the pivots because they reduce the torsional bending of the spring. Flipping the A-arm around is a three-link not four.

(Wait a sec...
"1/4 Eliptical" has nothing to do with the link design - as with a 4 link coils, coilovers, 1/4 eliptical, or leaf springs with shackles at both ensd are merely the method for suspending the vehicle, where the 4 link (or V link, etc.) is the method for axle location.)

You are correct!, what I was refering to was that with all the steps you are taking a three or four link is what you you are almost building. Why not do a three link cut your springs in half and do a three link 1/4 eliptic?

I believe what you are talking about when you refer to the torque bar is that you mean to say the the rotational force of the axle is being transmitted to the frame. If this is indead what you are talking about as you accelerate or decelerate the axie will try to rotate. This will place the upper links in tension or comppression depending on accelerateion or deceleration and the opposite for the lower links. What this means on the frame end of things is that a couple will be created. This means that at the point where your links attach there will be a force the is trying to rotate you frame. The closer the end of the links are together at the frame the less the magnitude of the couple. Either way this couple is relatively small and the weight of the vehicle will counteract an effects it has.

What i wanted you to understand about your original idea is that there will be little control of your side to side movement. It will be very unstable. You can use a panhard rod to stop that though. But that also adds another limiting factor.

"I just wanted to get everyone reading" Yes, I am God....I really don't care what you have to say, your an arrogant <IMG SRC="smilies/flipoff.gif" border="0">. You might want to leave acadamia long enough to learn a little more about people. You might just have something to say but none of us needs a grade from you so your not shit till you prove it. Most of what you see here isn't gossip its what people build that works, we got pictures. Show us the pictures of your work, not what you've read. Yes, your high and mighty attitude pisses me off.

[ 07-17-2001: Message edited by: FearMe ]

Dave, why not both? This is something I'd been thinking, and I can't visualize it just right in my head, but if you were to run the two links from the top of the axle to one, at the frame, but above the t-case output, and then run another set, mounted under the frame, from the two framerails down to one under the pumpkin (or at least under the 3rd, because under the pumpkin would suck up clearance...)...

...My big issue with the v on top of the pumpkin is that for the axle to rotate (flex-wise), it actually moves the pumpkin sideways, and thus shifts the truck's center of gravity OFF of the axle, TOWARDS the down-side of the slope... With it under, it would actually move the center of the axle off the axle, but towards the UPHILL, which, as far as I can figure, would be more stable...

But I have no practical experience. <IMG SRC="smilies/thefinger.gif" border="0">

Calpoly: I'm trying to get an email off to you, but just so you know, I want a pair of the steering arms, please! <IMG SRC="smilies/biggrin.gif" border="0">

The guys on here can build some of the most awesome link suspensions I have ever seen. If you want to learn something, ask questions from these guys and trade ideas. Don't think that your knowledge is soooo much greater than everyone elses. So back the fawk up and let everyone share their opinions and ideas. You're not always going to be right.

Erin

I know absolutly nothing about link suspensions. But fully agree with willymutt

Be carefull what you say. You may not want to meet some of these guys (and Girls) when your done.

willymutt, It you designed your car a little smaller, four wheel steering would not be needed. That was all i was trying to say. A far as the Girl goes she was nice to talk to but I didnt say she new anything about design.

We spent about $4000. In my opinion that is still too much. We are starting the new design tonight. Last year our car weighed 463 lbs. This year I will be doing most of the design and we are shooting for 300lbs.

Ant, Reading books has nothing to do with what I know. Many fellow ME (Mechanical Engineers) including myself have built suspensions for rock crawling. I have no idea what to design for when it come to circle track. Limiting straps are used throughout baja race vehichles but it is not intended to reduce anti-squat. There sole p urpose is to limit the amount of travel. Baja vehichles use a trailing arm rear suspension. They are not worried about articulation. When a Class 7 vehicle jumps it gets tremendous air and right before the jump the suspension is usually close to fully compressed. The stored energy in the springs will shoot the axle down as the vehichle leaves the ground. The axle then has a huge amount of momentum. To combat this rebound valving is added. Rebound valving can not be too high though or the axle with not drop fast enough to prepare for the landing. Therefore the axle still has momentum as it reaches the bottom of the stroke. If limiting straps were not in place shock damage would occur.

In responce to everyone, I am not saying I am the God of suspension design. What I was trying to do is get a little more technical discusion going by getting a response from my original comment. As every one knows no one knows everything and I do not claim to. I just wanted to throw in some engineering principales so that a greater understanding of suspension design could be learned. There are always little things that occur when designing anything that can not be anticipated, this is why I said that suspension design is an iterative process. You must build, test, evaluate, and redesign. There never was and never will be a perfect suspension design, but I believe as now that I have your attention that we as a group can come up with some pretty good ideas. I'm just throwing information out. I agree that many crawlers have good suspensions that work very well. And to the comment about anti-sqaut, yes a little is good. But watch the scorpion try to climb a steep hill and you will understand that too much will cause a loss of traction and cause the rear to hop as it tries to climb.

Glad I could raise some debate, it is the only way to really learn if you have an open mind! Keep the comments coming and I will do all I can to share what I know and you can correct me when I am mistaken. You won't hurt my feelings! When it all said and done we can all still have fun wheeling and enjoy a couple of beers together.

There is some good info here -- I'm enjoying the conversation. I hope the discussion keeps an information focus and minimizes testosterone... Ant, Fear, others... let's seriously talk about what WORKS on your trucks and what doesn't WORK -- and why. I seriously doubt that there's a PERFECT suspension out there...

This seems like a great opportunity to combine book 'larning and practical experience... they aren't necessarily mutually exclusive.

Randii (who has read the books, worked with modeling software, and applied some of that knowledge, but still can't make my snazzy pivoting-sliding axle-wrap prevention device work very well <IMG SRC="smilies/rolleyes.gif" border="0"> I ain't perfect.)

Originally posted by randii:
<STRONG>There is some good info here -- I'm enjoying the conversation. I hope the discussion keeps an information focus and minimizes testosterone... Ant, Fear, others... let's seriously talk about what WORKS on your trucks and what doesn't WORK -- and why. I seriously doubt that there's a PERFECT suspension out there...

This seems like a great opportunity to combine book 'larning and practical experience... they aren't necessarily mutually exclusive.

Randii (who has read the books, worked with modeling software, and applied some of that knowledge, but still can't make my snazzy pivoting-sliding axle-wrap prevention device work very well <IMG SRC="smilies/rolleyes.gif" border="0"> I ain't perfect.)</STRONG>

I agree randii but 'gods' sig file explains the problem I have kidding around another thing but I do believe he's serious about himself. And I ran out of testosterone years ago <IMG SRC="smilies/wink.gif" border="0">

Fearme,
I am not intending to make anyone feal small only to gain information and to give some. Testosterone can be substituted by using adrenaline!

DRM, there's a local flatfender here using an anti-wrap device which is, in effect, what you were describing. For all practical purposes, the side-to-side stability is as good as it ever was--in fact, he used it as a daily driver for a while. The pivoting, hinged "2-link" completely eliminates axle wrap, too.

Whether or not the theory says it'll work, in the real world it does.

Colpolystud, First of all, thanks for your insite. You are very good at explaining things so guys like me can understand where you are coming from.
Here is a picture of a 4 link set up I am playing with. Keep in mind that the size of the arms are not right because this is only a mock up so I can figure out what I should go with.
Constructive criticism is what I am looking for so fire away. <IMG SRC="smilies/biggrin.gif" border="0">
<IMG width=432 height=324 SRC="http://www.pirate4x4.com/ubb/uploads/quarter elipt mock.jpg">

[ 07-17-2001: Message edited by: desertoy ]

This seeems like a good place to ask as the thread I started about it got little attention. We've beat to death the rear suspension. What about the front? I'm curious to know if a 4 link 1/4 elliptical would work in the front and be stable on the road and trail.

Hell, I Love It!! <IMG SRC="smilies/bounce2.gif" border="0"> <IMG SRC="smilies/bounce.gif" border="0">
I could read this shit all day!! Nothing better than hearing therory and fact. And figuring out how to use it on my rig.

How many engineers does it take to screw in a light bulb? <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by calpolystud:
<STRONG>Fearme,
I am not intending to make anyone feal small only to gain information and to give some. Testosterone can be substituted by using adrenaline!</STRONG>

You won't quit will you? Your certainly not making me feel small or inadequate in your, self perceived, awe inspiring presence. The thing is you might not even know how arrogant you sound. It's a pity too because you probably do have a lot to say but it's the way you say it. Might just be wrongful perception on my part though, I'm not a god and often do make mistakes, so, sorry god, I apologize. You can continue the lecture from above.

[QUOTE]Originally posted by desertoy:
[

[ 07-17-2001: Message edited by: HeyBeerMan ]

For those of you who want pictures of some of the vehichles that me and my freinds work on here you go. More pictures will be added later.<IMG width=500 height=480 SRC="http://www.pirate4x4.com/ubb/uploads/FLEX%202.jpg"> <IMG width=390 height=480 SRC="http://www.pirate4x4.com/ubb/uploads/Dylan1.jpg"> <IMG width=500 height=480 SRC="http://www.pirate4x4.com/ubb/uploads/Dylan2.jpg"> <IMG width=564 height=402 SRC="http://www.pirate4x4.com/ubb/uploads/openh99.jpg"> <IMG width=640 height=480 SRC="http://www.pirate4x4.com/ubb/uploads/kev1.jpg"> <IMG width=640 height=480 SRC="http://www.pirate4x4.com/ubb/uploads/kev2.jpg"> <IMG width=296 height=449 SRC="http://www.pirate4x4.com/ubb/uploads/watkinsfrontroll.jpg">

Curtis,
If properly designed a 1/4 eliptic front could be done. The problem is that the front experiences greater side loads than the rear when cornering. What this means is that for the same vehichle a properly designed front 1/4 eliptic must be stronger than the rear. Space is usually the biggest problem though. To run a 1/4 eliptic without a panhard rod the links must have the correct geometry. This usually involves triangulated links under the oil pan and front drive shaft usually there is no enough clearance. So what end up happening is four parralell links in combination with a panhard rod which could make it hard for the 1/4 eliptic springs to fit. Thats why it is common to see a 4 link/panhard rod/coil spring setup.

Originally posted by calpolystud:
Dr.Mud
It is a four link becuse if I understand you correctly your leafs will still be attached to the axle and therefore are a link.

Well, not really - because a 4 link with coilovers would then be a 6 link according to your "math" <IMG SRC="smilies/tongue.gif" border="0">
Are you familiar with using shackles at each end of a leaf spring? In that configuration, the leaves only provide "suspension" (as in they support the weight of the vehicle on the axle) and the whatever link method you use is the "axle location" - serving only to (obviously) locate the axle under the vehicle.
But to a point - I am asking if the leaf springs mounted like this can also be a "link" to the suspension - since I am wondering if they would effectively replace/substitute-for a panhard bar.


Are you planning on decreasing the spring rate because the only way your are going to get "tons" more articulation is to decrease the spring rate. You will gain some frome the pivots because they reduce the torsional bending of the spring.

Reducing the spring rate would lower the load carrying capacity of the spring - not a good idea if they are rated correctly to start with.
Where you are gaining articulation is two-fold:
First, the ability of the additional bushings and shackles on both ends to allow the increased tortional movement of the spring leaves
The second gets a little more complicated, and gets back into the fuzzy line between what is a "link" and what is the "suspension" of the vehicle.
With a standard leaf spring suspension - the distance from the front eye (solid mount) to the axle is in effect - a "link" in that it locates the axle. AND, just like any other link suspension, articulation is limited by the distance from the front eye to the axle as it traved through it's arc. not only that, but you have the other end of the spring with the shacle to consider - though generally the limiting factor of any leaf spring suspension is the distance from the solid mount eye to the axle, not the shackle end.
Now, work some sort of link to locate the axle and put shackles at both ends of the spring. You are no longer limited by the spring since the distance from the front ee to the axle is no longer woring on a simple pivot, you get to add in the travel from BOTH shackles pivoting, allowing the spring to bend into an arch, and further drooping the axle form the vehicle.
true - this would not allow as much travel as 1/4 eliptical and some coils or coilovers (depending on applicaiton of course) - but this method is MUCH cheaper, and allows for the most part the same springs one were perhaps using before a link type suspension was implemented - with almost no changes to the springs themselves.

Anyway - rambled on enough about that.. <IMG SRC="smilies/tongue.gif" border="0">

Why not do a three link cut your springs in half and do a three link 1/4 eliptic?

Again - same 3 link can be applied to the full spring with shcakles at both ends for almost as much travel, lower cost, easier instalation and mounting, and easier "tweaking". it does have the drawback of not gaining the departure angle a rear 1/4 eliptical would - so you have to consider if that matters to you.

What i wanted you to understand about your original idea is that there will be little control of your side to side movement. It will be very unstable. You can use a panhard rod to stop that though. But that also adds another limiting factor.

Bingo - that is the info I was looking for. I knew I could limit "most" of the movement with several different methods - but as you said it would also start limiting articulation.

I was really exploring the V link suspension jsut to try something different. I have a friend with a CJ who runs a 3 link and has run the double shackle arangement I mentioned, but has since switched to rear coils instead. Here is his Jeep:
http://www.tennessee4x4.com/toyota/images/Creekbed5/cb5-10.jpg
http://www.tennessee4x4.com/toyota/images/Creekbed5/cb5-11.jpg

So basically my fallback is to emulate his 3 link, and use the double shackle setup like I described. His problems with it were due to running a VERY soft spring, and a BIG motor, where the vehicle would want to "torque squat" the rear pass. side when he got on the gas.

Anyway - enough of me rambling - I welcome ANYONE's suggestions/tips/advice on anything I have said here <IMG SRC="smilies/smile.gif" border="0">

[ 07-17-2001: Message edited by: DR. Mud ]

[ 07-17-2001: Message edited by: DR. Mud ]

Just got off work ...this is great!!!

desertoy,
If I can see the picture correctly it looks like your lower links attach below the transfercase. If I were to continue with your design I would triangulate the upper links as well. Position them on top of the Pumpkin. Let me explain a little theory. If you were to run imaginary lines extending from the end of your links to the point where they cross this is the first defining point of your roll axis. When you triangulate both set of links the roll axis becomes the line between the two imaginary points. What I am getting at is that you need to have these two imaginary points the same distance or as close as possible from the ground. If the roll axis is angled up (like most of the suspensions out there)you get oversteer. If the roll axis is angled down toward the front of the vehicle you get understeer. What this means to rock crawlers is that if your roll axis is angled a lot the one tire moves severly to the front and the other severly to the rear as the axle articulates. This also causes problems with anti-squat. The tire that has moved down now causes sever anti-squat and the tire that moves up causes squat. What this does is tries to twist your rear end and adds even more to the rear steer.

Let me know if you have any more questions!

It appears that the master has come out to play..................... <IMG SRC="smilies/tongue.gif" border="0">

I have been typing for four hours now and I need to get some lunch! I will come back and reply to as many people as I can in a little while. Keep the questions and discussion rollin. DR.Mud you will be first! <IMG SRC="smilies/eek.gif" border="0">

So do you think that this is too complicated of a design (triangulated upper and lower like you suggested) for my application (rock crawling rig that never sees the street)?
Is there any real advantage over a standard 4 link for my application?

Originally posted by calpolystud:
<STRONG>I have been typing for four hours now and I need to get some lunch! I will come back and reply to as many people as I can in a little while. Keep the questions and discussion rollin. DR.Mud you will be first! <IMG SRC="smilies/eek.gif" border="0"></STRONG>

Thanks <IMG SRC="smilies/smile.gif" border="0">


But lunch? I am cooking supper over here <IMG SRC="smilies/eek.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0">

I am sorry, from what I have seen, it seems like a good leaf spring suspension will do most anything you could ask.

Its simple, its easy, and it works.

I like to think about exotic suspensions just as much as the next person, though when it comes down to it I always come back to just plain leaves.

There are lots of rigs out there that work VERY well with just plain old leaf springs....Chris Durham, Sam Patton, etc...

Thoughts <IMG SRC="smilies/question.gif" border="0">

MAN......YOUR GOOD! SOLD!!! he's definatly a GOD!!!! your knowledge so exceeds mine I cannot compete. so tell me what have I been doing wrong on my suspensions all this time? Do you know of any books I could read to learn more about this? do you use a computer to figure out the links and lingths of them so you can see how the suspension reacts? are there programs for this to do this stuff on...Listen here is how it is in the real world... there is no perfect suspension OR rig. what you have done is talked a bunch of jibberish to ppl making yourself out to be a real guru when your not. 2 words about you. WEB WEELER. I have DELT with your type before. You over analize and over think everything Making sure it is PERFECT in every way. GOT NEWS FOR YOU. All that work trying to get your "roll axis" correct and link lingths correct has made you miss a very importand issue! FUNCTION!!Now you have 6' links that hang below the frame and are out in the open waiting for damage. BUT BY GOD that thing will articulate PERFECT!!! I wonder how well that handeling will be when you drive home with bent links. You going to write your own book on this soon??? I think it would make great toiletpaper! Get off your high horse and go home JOKE! I would compete with you and post pics of all the link systems and suspensions I have done or helped on over the last 7 years but I would probbly crash the server. <IMG SRC="smilies/thefinger.gif" border="0">

Originally posted by Mieser:
<STRONG>I am sorry, from what I have seen, it seems like a good leaf spring suspension will do most anything you could ask.

Its simple, its easy, and it works.

I like to think about exotic suspensions just as much as the next person, though when it comes down to it I always come back to just plain leaves.

There are lots of rigs out there that work VERY well with just plain old leaf springs....Chris Durham, Sam Patton, etc...

Thoughts <IMG SRC="smilies/question.gif" border="0"></STRONG>
I agree that it is the easiest way, but that doesn't mean it is the best way. Guys like me are willing to do the extra labor to make it BETTER for our application(rock crawling).
I think using Sam Patten is a bad example of Rock Crawling. Everyone knows he accomplishes everything with the GO pedal. I would like to be able to drive like he does. But my common sence and my wallet won't let me <IMG SRC="smilies/biggrin.gif" border="0">.

...shackles at each end of a leaf spring? In that configuration, the leaves only provide "suspension" (as in they support the weight of the vehicle on the axle)
Unless you don't attach the axle to the leaf springs (ever seen a drop-away axle? WEIRD), they still locate the axle at least a bit. Quite a bit, in terms of side-to-side, not so much front-to-rear, but still plenty to bind up during extreme travel and break parts.

With a standard leaf spring suspension - the distance from the front eye (solid mount) to the axle is in effect - a "link" in that it locates the axle.
A variable-length link, sure -- one that changes as the spring cycles through its arc.

Randii

What this means to rock crawlers is that if your roll axis is angled a lot the one tire moves severly to the front and the other severly to the rear as the axle articulates. This also causes problems with anti-squat. The tire that has moved down now causes sever anti-squat and the tire that moves up causes squat. What this does is tries to twist your rear end and adds even more to the rear steer.
...AND makes all onlookers <IMG SRC="smilies/laughing.gif" border="0"> if your high-travel beast looks like it is humping the rock, can't seem to get traction to the drooped tire, and generally wants to roll itself. <IMG SRC="smilies/biggrin.gif" border="0">

Seen it -- it was PAINFULLY funny.

Randii

MAN......YOUR GOOD! SOLD!!! he's definatly a GOD!!!! your knowledge so exceeds mine I cannot compete.
Gonna set up an upended bathtub shrine? <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

I wanna see him walk on water.

Randii

Randi,

Your right on Sam, I don't think he knows that the gas pedel just isn't an on/off switch <IMG SRC="smilies/tongue.gif" border="0">

What about Jason Paule then, his rig is really simple and works great. I know he is building something new now though <IMG SRC="smilies/smokin.gif" border="0">

I know about 5 years ago everyone was going coil in desert racing because it saved a TON of weight over 1/4 eliptic leaves. On a rockcrawler though, does it really save that much weight?

Personally I feel that most custom suspensions have WAY too much droop and not enough compresssion. It always seems like the tire just keeps going down and gets 'hooked' under a lot of things on the trail.

To use RTI as a bad example, there are plenty of streetable rigs that can ramp 1000 on a 30 degree ramp. Didn't Sam Patton do like a 950 at TTC last year? That is with a spring over, no shackle reversal, and like 2" springs right? Do we really need more flex than that.

I think that a lot of suspension problems I see could be fixed with better shocks, better leaf packs, etc...

Flex is cool to look at, but does it really work that well off road <IMG SRC="smilies/question.gif" border="0">

Originally posted by calpolystud:
<STRONG>Curtis,
If properly designed a 1/4 eliptic front could be done. The problem is that the front experiences greater side loads than the rear when cornering. What this means is that for the same vehichle a properly designed front 1/4 eliptic must be stronger than the rear. Space is usually the biggest problem though. To run a 1/4 eliptic without a panhard rod the links must have the correct geometry. This usually involves triangulated links under the oil pan and front drive shaft usually there is no enough clearance. So what end up happening is four parralell links in combination with a panhard rod which could make it hard for the 1/4 eliptic springs to fit. Thats why it is common to see a 4 link/panhard rod/coil spring setup.</STRONG>


Curtis
One point that has not been mentioned is steering...
With a traditional 3 link or triangulated 4 link, when the suspension is cycled the drag link will travel in a much more extreme arc than the axle...
Example:when the right side tire is cycled up or "stuff'd" the steering will tend to to forced right, which will limit your steering to the left... and vise versa..
this is unless your drag link is level to the ground when at rest... (unlikely)

This is why it is better to use a Panhard on the front that mounted from right to left and is as close as possible to the same lenght and angle as the drag link..
this will force the axle to travel in the same arc as the drag link and will greatly improve steering...


For proof see John's Rock Truggy..
he ditched the triangulated 4 link in favor of a parallel 3 link w/panhard..

***now if your running hydrolic steering, forget everything i just said*** <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

Maybe I am missing something but if you read ALL of what calpolystud is saying, it seems to me that he is explaining why SnortClowns suspension works soo well.
Personally I am going to take all of this kind of technical information that I can retain and use it as a tool, not a bible.
That said, Will someone explain roll axis again. I havent grasped the basics of that yet <IMG SRC="smilies/confused.gif" border="0">

Originally posted by randii:
<STRONG>[b]
Gonna set up an upended bathtub shrine? <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

I wanna see him walk on water.

Randii</STRONG>

Your such a good mediator Randii! <IMG SRC="smilies/biggrin.gif" border="0"> On the other thread you spoke of a slalom issue with flat towing...It's really not an issue! AT ALL. the things this guy speaks of are true but not as sevear as he makes them out to be.. In 99% of the cases you would never even notice then nor would they prevent you from going somewhere or killing someone. Not just my .02 but a fact I have expirenced in the real world. <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by Mieser:
<STRONG>I am sorry, from what I have seen, it seems like a good leaf spring suspension will do most anything you could ask.

Its simple, its easy, and it works.

I like to think about exotic suspensions just as much as the next person, though when it comes down to it I always come back to just plain leaves.

There are lots of rigs out there that work VERY well with just plain old leaf springs....Chris Durham, Sam Patton, etc...

Thoughts <IMG SRC="smilies/question.gif" border="0"></STRONG>


You couldn't be more right!!!
Simple and effective...
The only problem is axlewrap??

Shit, I have a set of CLAPPED out reversed arched broken leaf'd hand me down springs and I run the crap out of um...
The last time I checked I ramped a 589
<IMG SRC="smilies/eek.gif" border="0">
BUT it a well BALANCED peice of NON flex'n shit and Like I've always said and will always say..

IT'S NOT WHAT YOU DRIVE, IT'S HOW YOU DRIVE IT!!!!


yeah, i'm gonna go link f/r but not because I NEED to, but because it's soo much fun to build!! <IMG SRC="smilies/biggrin.gif" border="0">

I'd just like to thank you on your last post, I believe, because I now have the reason why my rear end steers. Not that I am going to do anything about it, because I made it such that my links are no lower than my drive line but right in line with it so that I don't constantly hit my drive line on the rocks but kinda spreads it out, for less damage occurace in my rational. It's nice to know why my suspension doesn't work the way I wanted it to, but from this reading it seems in order to have level links at rest you gotta have your mounts so low that I agree with SNortclown, you'd just be draggin it on everything. So, I have yet to hear someone tell me how to have the best of both worlds. I got my start looking at Sam's design. I like it that he didn't have rear steer, and it articulated like mad, but I didn't like that dingus hanger of his hanging way down to snag on stuff. So I used the top link, or A arm, because it is relatively break free, cheap to build, and the only thing that will ever need to be replaced is the rubber radius arm bushings that cost me $6.75 from Shucks. To me, that was better than having heim joints that you have to replace every year or run the risk of breaking which cost an insane amount of money. I had to break down and buy a couple of tractor hiem joint for the other two links, but i only run them at one end up at the t-case and the other end I run bushings. I guess I'm more into not breaking and wheeling, and maybe my suspension doesn't move like I first wanted it to, but I'm not stuck up on rocks or whatever because I gave in and had mounts hanging out ready to grab hold the nearest rock. Got any advice? Sure I'll listen but sometimes good advice has bad possibilities of it's own.

I'm sorry to post again but I just re read the first paragraph by the GOD him self here it is and I quote

"This is the reason a mildly modified Wrangler with leaf springs climbed the (A-7) obsticle that the Scorpion could not at the last ARCA event in Cedar city. With a large percentage of Anti-Squat the rear end of the vehicle will lift under acceleration. In the case of the Scorpion this causes the rear end to try to drive forward under the vehicle while the vehicle remains still. The result is the vehicle develops a condition similar to axle-wrap. The rear end starts to hop causing a decrease in traction."


hehehe Ok here We go!!!! You MORON!! you call yourself a GOD well guess what CLOWN I'm here to show you what a F%$#ing Moron you really are. the scorpion does not have the problem you explained. KNOW WHY???? because it has 0 rear steer and the axel does not drive forward. the problem comes from energy transfer from opposing corners as it articulates and is largly caused from its front to rear CG as it loads 1 corner say in an offcamber up hill on the right side the weight is transferred to that corner. It's natural reaction is to squat that corner pushing the front right tire down and the left rear down. this causes the left fron tire to carry. All your linkage geometry has NOTHING to do with this suspension design and it cannot be used as an example. It cannot steer. Look how it is mounted it pivots on a center axis then pivots again with a swingarm design same in front than uses equalizer bars. SO since this suspension reacts NOTHING like a 4 link I beg you to try again! and another thing for you head thete MR guru the scorpion is hinderd in alot if terraine because all his SHIT HANGS LOW!!!!! but on the other hand it is very complex and ingenius in it's design.

Originally posted by randii:
Unless you don't attach the axle to the leaf springs (ever seen a drop-away axle? WEIRD), they still locate the axle at least a bit. Quite a bit, in terms of side-to-side, not so much front-to-rear, but still plenty to bind up during extreme travel and break parts.

Front to back location? Not one Bit <IMG SRC="smilies/tongue.gif" border="0">

A variable-length link, sure -- one that changes as the spring cycles through its arc.


Wrong answer <IMG SRC="smilies/wink.gif" border="0">

The front half of the leaf spring is a "link" with a working distance of the flat length (measured along the length of the main spring leaf, not "through the air" sistance) from the front eye to the axle. It cannot EVER be longer, but it can be shorter.

For example, the springs I am currently using on the front of my truck are 20.5" from the front eye to the axle. the axle can NEVER get further away from the front eye as ot travels through it's arc of movement - it will always be at most 20.5" from the front spring eye pivot point.

Originally posted by SNORTclown:
<STRONG>I'm sorry to post again but I just re read the first paragraph by the GOD him self here it is and I quote

"This is the reason a mildly modified Wrangler with leaf springs climbed the (A-7) obsticle that the Scorpion could not at the last ARCA event in Cedar city. With a large percentage of Anti-Squat the rear end of the vehicle will lift under acceleration. In the case of the Scorpion this causes the rear end to try to drive forward under the vehicle while the vehicle remains still. The result is the vehicle develops a condition similar to axle-wrap. The rear end starts to hop causing a decrease in traction."


hehehe Ok here We go!!!! You MORON!! you call yourself a GOD well guess what CLOWN I'm here to show you what a F%$#ing Moron you really are. the scorpion does not have the problem you explained. KNOW WHY???? because it has 0 rear steer and the axel does not drive forward. the problem comes from energy transfer from opposing corners as it articulates and is largly caused from its front to rear CG as it loads 1 corner say in an offcamber up hill on the right side the weight is transferred to that corner. It's natural reaction is to squat that corner pushing the front right tire down and the left rear down. this causes the left fron tire to carry. All your linkage geometry has NOTHING to do with this suspension design and it cannot be used as an example. It cannot steer. Look how it is mounted it pivots on a center axis then pivots again with a swingarm design same in front than uses equalizer bars. SO since this suspension reacts NOTHING like a 4 link I beg you to try again! and another thing for you head thete MR guru the scorpion is hinderd in alot if terraine because all his SHIT HANGS LOW!!!!! but on the other hand it is very complex and ingenius in it's design.</STRONG>i knew this was comin <IMG SRC="smilies/rolleyes.gif" border="0">all my knowledge is from trial and error.maybe im a caveman but thats how i do it.this is a very interesting discussion to say the least.tear it up SNORTclown

<IMG SRC="smilies/thefinger.gif" border="0"> <IMG SRC="smilies/thefinger.gif" border="0">

all the design work in the world is no good if you are a crappy fabricator and do cobby work .. in rockcrawling at the speeds we run some rear steering is not going to hurt and some anti squat is a very good thing for increasing traction ..
i have seen designs that were way over thought by your types and still work like crap and i have seen designs that were thrown together by people with no knowledge of link geometry that work killer , in design and fabrication you either have it or you dont ...
lets see your work in real life situations and it better not be some cobby ass crap there god !

QUOTE]Originally posted by Ant:
<STRONG> Originally posted by calpolystud:
Ant,
You are putting a band-aid on a gun shot wound. With proper design a limiting strap wouldn't be needed. But if you have fun in your rig thats all that count right?</STRONG>
Scuse me?? You can read all the books you want and none will tell you how to build proper "Rock Crawling" 4-link suspension all your books are based on drag racing circle track and baja racing. I feel extra anti-squat is good and I just added the limit strap to keep the axle from trying to walk under the rig, the design was intentional. A lot of people on this thread seem to have actual experience building and using link suspension, do you??? And why don't you tell every baja racer that they "band-aided" their suspension, cause last time I looked every truck in the Baja 1000 was running limit straps!!!
<IMG SRC="smilies/laughing.gif" border="0">

[ 07-17-2001: Message edited by: Ant ][/QUOTE]
I have to agree with Ant on this one, as a guy who has probably cut more experimental suspension designs off his rig than the "stud" has ever made, a center mounted limiting "strap" ( personally I use aircraft cable...) is a very useful thing for keeping the rear driveline from going BANG!
Also as a student of the sport of 'wheeling a modified rig , the link suspension information available from "book sources" is not as valuable as the "stud" seems to think it is, roll center, anti-squat, even CG are easy things to quantify if things like traction and speed/acceleration can be predicted, an easy thing to do if the surface you are dealing with is paved....
if the surface is a 20' tall boulder with 2 little flags on it as wide as your track width, and you have only 4 minutes to complete........

oh yeah while we are showing pix of trucks on ramps....... <IMG SRC="smilies/rolleyes.gif" border="0"> <IMG SRC="smilies/rolleyes.gif" border="0">

<IMG width=434 height=346 SRC="http://www.pirate4x4.com/ubb/uploads/nw ramp.JPG">


<IMG SRC="smilies/tongue.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0">

[ 07-17-2001: Message edited by: AIRZUKI ]

BBAAAAAAAAAHHAHAHHAHAHHAHAHAHHAHAHAHAHHAHAHAHHAHAH AHHAHAHAHHAHAHAHAHAH

<IMG SRC="smilies/rolleyes.gif" border="0"> <IMG SRC="smilies/rolleyes.gif" border="0"> <IMG SRC="smilies/rolleyes.gif" border="0"> <IMG SRC="smilies/rolleyes.gif" border="0"> <IMG SRC="smilies/rolleyes.gif" border="0"> <IMG SRC="smilies/rolleyes.gif" border="0"> <IMG SRC="smilies/rolleyes.gif" border="0">

<IMG SRC="smilies/confused.gif" border="0">

Originally posted by calpolystud:
<STRONG>Curtis,
If properly designed a 1/4 eliptic front could be done. The problem is that the front experiences greater side loads than the rear when cornering. What this means is that for the same vehichle a properly designed front 1/4 eliptic must be stronger than the rear. Space is usually the biggest problem though. To run a 1/4 eliptic without a panhard rod the links must have the correct geometry. This usually involves triangulated links under the oil pan and front drive shaft usually there is no enough clearance. So what end up happening is four parralell links in combination with a panhard rod which could make it hard for the 1/4 eliptic springs to fit. Thats why it is common to see a 4 link/panhard rod/coil spring setup.</STRONG>

Ah, cool. I'll have to check to see if I can run the links up front without oil pan/drive line problems. Of course this is all gonna start when I get my 60s later in the year.

Originally posted by Tin Bender:
<STRONG>
Curtis
One point that has not been mentioned is steering...
With a traditional 3 link or triangulated 4 link, when the suspension is cycled the drag link will travel in a much more extreme arc than the axle...
Example:when the right side tire is cycled up or "stuff'd" the steering will tend to to forced right, which will limit your steering to the left... and vise versa..
this is unless your drag link is level to the ground when at rest... (unlikely)

This is why it is better to use a Panhard on the front that mounted from right to left and is as close as possible to the same lenght and angle as the drag link..
this will force the axle to travel in the same arc as the drag link and will greatly improve steering...


For proof see John's Rock Truggy..
he ditched the triangulated 4 link in favor of a parallel 3 link w/panhard..

***now if your running hydrolic steering, forget everything i just said*** <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"></STRONG>

When you say from right to left, would that be from right side of axle to left side of frame? Panhard bar in the front wouldn't be bad, IMO. But, I am seriously considering hydrallic steering for the front anyway so it may be moot. But, thanks in case I decide to stay with the steering I have <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by fj junkie:
<STRONG>all the design work in the world is no good if you are a crappy fabricator and do cobby work .. in rockcrawling at the speeds we run some rear steering is not going to hurt and some anti squat is a very good thing for increasing traction ..
i have seen designs that were way over thought by your types and still work like crap and i have seen designs that were thrown together by people with no knowledge of link geometry that work killer , in design and fabrication you either have it or you dont ...
lets see your work in real life situations and it better not be some cobby ass crap there god !</STRONG>


Hahahaha.... you just described me FJ. I can't fabricate and I know squat about geometry, but mine actually turned out decent by some standards and great by my own standards. I designed mine to have no rear steer (though I have front link steer, go figure). It works well, but I wouldn't say that it is the answer, only one option.

I drove Mark's rig from SNORT last year on the con and had a blast. His had tons of rear steer, but boy was it ever fun. It took me a couple minutes to learn how it worked and what it would do, but once I did, I walked everything that I pointed it at. My point is, rear steer, no rear steer, don't bother me..... I'm wheeling and having a good time.

Here is my rig that has no rear steer and is hacked together.

http://www.sierrarockcrawlers.com/images2/1005.jpg

-Sam

Originally posted by Sam:
<STRONG>


I'm wheeling and having a good time.

Here is my rig that has no rear steer and is hacked together.

http://www.sierrarockcrawlers.com/images2/1005.jpg

-Sam</STRONG>

sam has it right he is wheeling and having fun even if he's a hack <IMG SRC="smilies/thefinger.gif" border="0">

Originally posted by calpolystud:
<STRONG>For those of you who really don’t understand what your talking about when it comes to designing a link type suspension let me fill you in on a lot of stuff.</STRONG>


Damn you are a cocky son of a bitch. Go away and come back when you learn how to start a conversation without calling everyone an idiot as soon as you open your mouth. The sad part is that you might actually have something valuable to add but since you are a dick most people aren't going to listen.

Right back at ya Fab Five Freddy <IMG SRC="smilies/thefinger.gif" border="0"> Oh wait, you aren't a hack, but you still get the Wheel On.

-Sam

Originally posted by SNORTclown:
<STRONG>I'm sorry to post again but I just re read the first paragraph by the GOD him self here it is and I quote

"This is the reason a mildly modified Wrangler with leaf springs climbed the (A-7) obsticle that the Scorpion could not at the last ARCA event in Cedar city. With a large percentage of Anti-Squat the rear end of the vehicle will lift under acceleration. In the case of the Scorpion this causes the rear end to try to drive forward under the vehicle while the vehicle remains still. The result is the vehicle develops a condition similar to axle-wrap. The rear end starts to hop causing a decrease in traction."


hehehe Ok here We go!!!! You MORON!! you call yourself a GOD well guess what CLOWN I'm here to show you what a F%$#ing Moron you really are. the scorpion does not have the problem you explained. KNOW WHY???? because it has 0 rear steer and the axel does not drive forward. the problem comes from energy transfer from opposing corners as it articulates and is largly caused from its front to rear CG as it loads 1 corner say in an offcamber up hill on the right side the weight is transferred to that corner. It's natural reaction is to squat that corner pushing the front right tire down and the left rear down. this causes the left fron tire to carry. All your linkage geometry has NOTHING to do with this suspension design and it cannot be used as an example. It cannot steer. Look how it is mounted it pivots on a center axis then pivots again with a swingarm design same in front than uses equalizer bars. SO since this suspension reacts NOTHING like a 4 link I beg you to try again! and another thing for you head thete MR guru the scorpion is hinderd in alot if terraine because all his SHIT HANGS LOW!!!!! but on the other hand it is very complex and ingenius in it's design.</STRONG>

Sorry Snort but I believe CalPolystud is right. Soni had to add a air bag on the droop side to control the rear axle from walking under itself. If you look at a picture of the rear suspension you can see a air bag on each side of the swinging arm.

I have a question for you all. Why is rear steer bad? We are not doing 120 mph. Why are you guys so worried about it. I have never drive a 4 linked rear so I have no idea. Please enlighten us none 4 link people. Does leafs in the rear have rear steer also?

Ok. So I just spent 15 minutes reading this trying to give calpoly the benefit of the doubt. Truth is, we've had better discussion on multi-link suspsension without you, book boy. Take a few minutes, hit the search button and come out again. But to start what must have been your first post with only the arrogance that an academiac can muster is irritating.

Too bad, because if you really had anything to add I was willing to listen - I'm building all this shit too. As it is, you're irritating.

DRM - my hats off to you for keeping to the tech side.

Paul

Rear steer is bad because if the rear drops into a hole the axle has to travel backward to drive out of the hole when going forward.

I have been reading this shit all day and I can't help but to start rolling around on the ground laughing...

Tin Bender, CALPOLYPUD does not equall Brian. When are you going to come up to Morro Bay and kick it on the beach? Cal Poly dude, who are you?

Brian: Greg=CalPolyStud...up for for the CON this weekend??? Poly Goat run...

[ 07-17-2001: Message edited by: Pig Pen ]

Originally posted by Donovan:
[QB]Sorry Snort but I believe CalPolystud is right. Soni had to add a air bag on the droop side to control the rear axle from walking under itself. If you look at a picture of the rear suspension you can see a air bag on each side of the swinging arm.
QB]

Ummm yeah! Ok! and look because the articulation is transfered through equalization bars in the center and the rear and front rotate at one center piviot point for articulation it has no rear steer causing the problem described from the origional post or the excuse for it not being able to make the "A7 climb" at ARCA this past weekend. Point these outer bags out so I can see them. AND in that suspension design if one side where to try and walk under the vehicle it would walk both sides forward since they are u-bolted solid to the swingarm.
http://www.scorpionvehicles.com/scorpionrear.htm
http://www.scorpionvehicles.com/climbin.htm
http://www.scorpionvehicles.com/twisted.htm

Originally posted by Richie:
<STRONG>Tin Bender, CALPOLYPUD does not equall Brian. When are you going to come up to Morro Bay and kick it on the beach? Cal Poly dude, who are you?</STRONG>

Whewww GOOD thing!!!!
I've run with you a couple times and it just didn't seem like you.... Do you know him (greg)??? I'm gonna have to make a trip real soon if I wanna see Camo's rig in a pile <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

I'm gonna have to shuffle some cage jobs around, but i'm sure I can get some time <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/beer.gif" border="0">

Hey God, Bring your rig, if you have one, up to the con this weekend with pig pen so i can drive over it. i have never taken an enginering class but have built three rigs with ample flex. I have friends that are engineers. They come up with ideas that wont work, ask me why, i tell them and them build it for them. My best bud is a machinest and deals with engineers all the time. he says that they are so dense that they dont understand why a 5" id pipe wont slide inside another 5" id pipe. Come on. Learn how to do it with yout hands before you learn how to do it with your mind.

Everytime i have to work on a factory built car i realize how dense engineers really are. They, and you GOD, base your theorys on math, not logic. On ideas, not reality.

By the way, why don't you work up an equation for me and figure out how much lateral force it would take for you to pull your head out of your ass. Dave Jackson

HAHAHAHAHAHAHA that was funny.......GOD, would you care to respond to Jackson????????? <IMG SRC="smilies/rolleyes.gif" border="0">
PS. Jackson it seems to me that if your rig had ample flex it wouldn't have rolled off that little tinny ledge at the begining of the bowl...

[ 07-17-2001: Message edited by: Pig Pen ]

Originally posted by Pig Pen:
<STRONG>HAHAHAHAHAHAHA that was funny.......GOD, would you care to respond to Jackson????????? <IMG SRC="smilies/rolleyes.gif" border="0">
PS. Jackson it seems to me that if your rig had ample flex it wouldn't have rolled off that little tinny ledge at the begining of the bowl...

[ 07-17-2001: Message edited by: Pig Pen ]</STRONG>

PS Dave, it seems to me that if cal poly is such a fine institution of engineering, they could have taught you how to weld your axel perches to your housing without having both of them break and rotate at the same time. I know that you and your stick rarely get penatration, but come on, it aint that hard, or maybe thats the problem.

All puns intended. Dave

PPS. Let me know if you need a ride this weekend or if you want to ride with me. I have a seat open but will fill it if you take your jeep. Pete's going to meet us up there friday night. Call me tomorrow.

The real Dave.......

Originally posted by calpolystud:
<STRONG>For those of you who want pictures of some of the vehichles that me and my freinds work on here you go. More pictures will be added later. <IMG width=390 height=480 SRC="http://www.pirate4x4.com/ubb/uploads/Dylan1.jpg"> </STRONG>

WOW, maybe you should take at look at your pics, and then take another look at what your preaching Mr. Almight! Those links sure don't look parallel to me. <IMG SRC="smilies/rolleyes.gif" border="0"> and if you really did know anything about how things work in the real world instead of your classroom environment, then you would know how dumb those lower links are. Did you ever think that just maybe those things are going to get caught up on everthing and get bent to shit?? Then on the jeep on the ramp, it sure looks to me like there is some rear stear going on there, but maybe I'm wrong..... yeah right! http://www.contrabandent.com/pez/otn/angry/nono.gif
Maybe you should go over to the JU board and blow smoke up people's ass'...... I'll bet they'll buy it. <IMG SRC="smilies/thefinger.gif" border="0"> <IMG SRC="smilies/thefinger.gif" border="0">

Originally posted by calpolystud:
<STRONG>willymutt, I was talking to your team leader or mabe your advisor, "the Girl", at the awards banquet in Manhattan, very smart girl. I give you guys credit for the four wheel steering. It was a nice touch. I don't believe it was neccisary (too much weight) but i bet it scored brownie points with the judges. Wait till you see our next car! See you in El Paso!</STRONG>

Yeah, the four wheel steering was way do much weight, that why we kicked everyone's ass in the hillclimb, huh? And for browine point, ha, them dumb ass judges didn't think it would work.
And as for the suspension being diffrent on a Baja then a rockcralwer, this is true but the same principles still apply and if you can build a kick ass baja suspesion then I highly doubt you'll have any problems with a rock cralwer suspension.

Neckster, I don't know what kind of material, grey cast iron???, you are using for for your lower links but we choose to use a 1020's series DOM. The links on the Yota are 1 5/8 .25 wall. The truck has been beat on severly and has not bent shit for the 2 years the link suspension been on there. As for the links being parallel, its a give and take sort of situtatiion (as stated above). Angle up=+anti squat, roll axis flat=zero rear steer. It is a compermise of both characteristics. On the Jeep with the rear steer, it was not calpolystuds fault it was Kev's, just a little misscalculation. You guys just need to come to the conclusion that calpolystud knows his shit... As for Weasel
Originally posted by Weasel:
<STRONG>if you can build a kick ass baja suspesion then I highly doubt you'll have any problems with a rock cralwer suspension.</STRONG>
Obviously you did not see our suspension last year cause it was soakin up the bumps like they weren't even there. As for the hill climb...what a joke. The only reason we didn't place higher is cause of some bullshit penalties from BYU and I rolled it and broke the cain in the endurance race.

[ 07-18-2001: Message edited by: Pig Pen ]

[ 07-18-2001: Message edited by: Pig Pen ]

Originally posted by Pig Pen:
<STRONG>You guys just need to come to the conclusion that calpolystud knows his shit </STRONG>


What would make you come to that conclusion?? I have seen no proof that he knows shit about anything besides textbook. Am I just supposed to take your word or his that he is a "God"........ please, go try and impress someone else. If he merely wanted to come on this board and try to help people out, there are alot better ways of handling himself. As it looks now (IMHO), most ppl think he is either an arrogant prick, or they think that he is pencil pushing desk jockey that doesn't know shit about the real world.

Originally posted by nasvik:
<STRONG>DRM - my hats off to you for keeping to the tech side.</STRONG>

Yeah - and what's with that? <IMG SRC="smilies/confused.gif" border="0"> *I* am supposed to be the one ranting and raving off topic with personal attack slurs... If even *I* am not doing that, some of these guys should stop and wonder <IMG SRC="smilies/eek.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by calpolystud:
<STRONG>Anti-Squat is a property that determiners how much the rear will raise or lower when accelerating. This is the reason a mildly modified Wrangler with leaf springs climbed the (A-7) obsticle that the Scorpion could not at the last ARCA event in Cedar city. With a large percentage of Anti-Squat the rear end of the vehicle will lift under acceleration. In the case of the Scorpion this causes the rear end to try to drive forward under the vehicle while the vehicle remains still. The result is the vehicle develops a condition similar to axle-wrap. The rear end starts to hop causing a decrease in traction.</STRONG>

Originally posted by calpolystud:
<STRONG>AirBag, You are correct! Anti-squat is a big killer when it comes to climbing steep angles. .</STRONG>

Do I see a slight contradiction here? Obstacle A7 was primarily a "steep climbing angle."

Obstacle A7 was one of the (if not considered the hardest) obstacle of the Cedar City ARCA. With a very strong inclination. I cannot give exact degrees on this, but by visual view it was very close to vertical. But then your Wrangler made it.

For those that was not there and I WAS most of the vehicles that made it up this inclination were more of light weight.

A buddy of mine made obstacle A7. It was his first comp. and he did not do as well on some of the other obstacles thoughout the comp. BU-UT he DID A7 and did not point out.

Then again my other buddy did better on some of the other obstacles.

I did not have to opportunity to see Walker Evens "Climb" A7 but from what I understand he did it as well. Hmmmm What suspension did he have?

I am not contradicting your engineering knowledge or degree which I respect to the fullest. However, I may just be questioning your actual real life knowledge. I do not know about other people on this BB but I would like to see more. The Pic that you showed does not show me enough to convince me.

Besides the fact that the Wrangler that you speak of (which is a great rock crawling machine, if it is the one I believe I saw) was not in the top rank. You really need to have more to back your theory. I am an open minded person. However, I have seen in ACTION (In particular, Roggy Fabrication and SC&N Fabrications) what the some of these guys on this BB has put out as far as suspension, etc. Not to say anything bad about your Toy Pic because that is a great vehicle for places like the Rubicon and maybe doing the hammers without flags, but that is child's play compared to the comp vehicles.

Again I state that I am not saying you are not a great engineer but need proof.

[ 07-18-2001: Message edited by: 4x4Grrl ]

[ 07-18-2001: Message edited by: 4x4Grrl ]

Hey Lance - you forget to log Kelly off again? <IMG SRC="smilies/tongue.gif" border="0">

If not, DANG KELLY <IMG SRC="smilies/eek.gif" border="0"> - I got new respect for your wheelin' knowledge <IMG SRC="smilies/wink.gif" border="0">

I wasn't even able to get through the first page before me head started pounding!! <IMG SRC="smilies/confused.gif" border="0"> <IMG SRC="smilies/confused.gif" border="0"> <IMG SRC="smilies/confused.gif" border="0">
________
easy vape review (http://vaporizer.org/reviews/easy-vape)

Im assuming that was actually LANCE, that made that last post...(although if it was Kelly, im saying "KIICK AZZZ" in my Cartman voince)


either way, Cal-poley-pud, is an arrogant SOB. Have fun in the real world boy, as your attidude isnt really going to make friends and impress others wherever you end up workinig...just remember that unless you work as a drone engineer tucked away in some cubicle for Mega-big Inc. you will, as an engineer will be forced to interact with people whom have no engineering background yet have a hell of a lot more power than yourself. You best learn to check yourself.

This thread has been informative, too bad i dont give a rats ass about these types of suspensions.
For those of us whom have an interest in such things im sure they have had a fun time picking your brain...but be advised i dont get the feeling that youd be missed.

[ 07-18-2001: Message edited by: El Taco ]

Meiser - How do you know Jason? He is building something else right now, but being able to compete with a SOA CJ7 says a lot. What about Tracy Jordan also. He won with a SUA! How is that for old school. He is working on something new also.

Leafs are the way to go.

Erin

Originally posted by Pig Pen:
<STRONG>Originally posted by Weasel:
[qb]if you can build a kick ass baja suspesion then I highly doubt you'll have any problems with a rock cralwer suspension.</STRONG>
Obviously you did not see our suspension last year cause it was soakin up the bumps like they weren't even there. As for the hill climb...what a joke. The only reason we didn't place higher is cause of some bullshit penalties from BYU and I rolled it and broke the cain in the endurance race.QB]

Yeah, there was noone close to our time in the hill climb. It wasn't just a fluke either. We came back in the afternoon and ran the fast time again. As far as the endurance race goes, we had a skidplate problem. That took us out of the running. We had to stop and fix it too much. I think that we gave everyone a run for their money. When you come from 20 something place after the static events, and then start the endurance race 3rd and 4th, I think that everyone was watching. What school were you part of Pig Pen.

Heah Craig, it's Erin. I finally got my jeep running.

Erin

Originally posted by SNORTclown:
<STRONG>Ummm yeah! Ok! and look because the articulation is transfered through equalization bars in the center and the rear and front rotate at one center piviot point for articulation it has no rear steer causing the problem described from the origional post or the excuse for it not being able to make the "A7 climb" at ARCA this past weekend. Point these outer bags out so I can see them. AND in that suspension design if one side where to try and walk under the vehicle it would walk both sides forward since they are u-bolted solid to the swingarm.
http://www.scorpionvehicles.com/scorpionrear.htm
http://www.scorpionvehicles.com/climbin.htm
http://www.scorpionvehicles.com/twisted.htm</STRONG>


If you look at the first link you have, you can see the little air bag to the right.

WOW......... this is a good topic. Lots of good info , and bad. To me , it is important to have a well rounded rig. One that flexes well, but not to the point of sacrificing trail prowice. A rig that rides well , and doesn't go squirlley on the road between trails. Having the front and rear in ballence is an important factor as this reduces roll over. I think it is imposible to get everything out of a trail rig. You will always sacrifice something. ground clearance is the key, and its hard to design around it, without some sacrifice. My suspension is simple, and works. 3/4 elliptic rear, Wristed Ford arms up front.
CJ7 leaf springs rear and stock TJ coils up front. I have competed in local RockCrawls and won, and came 1st on the RTI in the Ramsey Nationals in Pa. My rig is trailered, but I know I can drive it at 60 on the Hwy.

Personally I don't think theory is worth shit. Like Airzuk, I have done more to my truck than it would take a engineer to figure out the bending moment of a link.

"Building a rig is my Hobby, offroading is just the testing grounds"

MudLite


85 Suzuki Hybrid:4.3 chevy, 700R4,Spicer 18, D44 front and rear, 5.38 gears, spooled rear, detroit front, CJ7 3/4 eliptic, wristed Ford Arm, TJ coils, 6 point cage, Hydrolic Assist, Warn 8's front and rear, 38.5x14.5x15 TSL sx's on beadloc 10" Rims, and Linex exterior Aqua paint.

Originally posted by DR. Mud:
<STRONG>Hey Lance - you forget to log Kelly off again? <IMG SRC="smilies/tongue.gif" border="0">

If not, DANG KELLY <IMG SRC="smilies/eek.gif" border="0"> - I got new respect for your wheelin' knowledge <IMG SRC="smilies/wink.gif" border="0"></STRONG>

Nope, that wasn't me.... It was Kelly.

<IMG SRC="smilies/ghost.gif" border="0"> <IMG SRC="smilies/ghost.gif" border="0"> <IMG SRC="smilies/ghost.gif" border="0"> <IMG SRC="smilies/ghost.gif" border="0"> <IMG SRC="smilies/ghost.gif" border="0">

Originally posted by Lance:
<STRONG>Nope, that wasn't me.... It was Kelly.</STRONG>

Then Kelly - awesome SMACK DOWN <IMG SRC="smilies/eek.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

You dont need links with IFS BABY!!!
IFS RULES !! <IMG SRC="smilies/thefinger.gif" border="0"> <IMG SRC="smilies/thefinger.gif" border="0"> <IMG SRC="smilies/thefinger.gif" border="0">

Originally posted by Snowball:
<STRONG>You dont need links with IFS BABY!!!
IFS RULES !!</STRONG>

Exactly why Hummers ROCK off road <IMG SRC="smilies/rolleyes.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0">

<IMG SRC="smilies/laughing.gif" border="0"> <IMG SRC="smilies/laughing.gif" border="0"> This is fun readin.

Originally posted by DR. Mud:
<STRONG>Hey Lance - you forget to log Kelly off again? <IMG SRC="smilies/tongue.gif" border="0">

If not, DANG KELLY <IMG SRC="smilies/eek.gif" border="0"> - I got new respect for your wheelin' knowledge <IMG SRC="smilies/wink.gif" border="0"></STRONG>


No it was me, Kelly. Lance was probably asleep when I typed it (he is in Bakersfield, CA right now). I woke up and could not sleep.

I thank you for the comment. I may have more than the average because it is where my interest lies. <IMG SRC="smilies/smile.gif" border="0"> And yes I do work on them too.

Ok, I'm Back!

Let's get some things straight here first!

1) I have never read a book on suspension design!

2) My knowledge comes from talking with people who have built rock crawling designs! They also have a good idea of what they are talking about.

3) I am not arogant (SNORTFOOLS!), As I stated before I originally posted this topic to get some interesting edjucated discusion going. I used a arogant heading to get people to look. If the SNORTCLOWN had read all of the replies before replying he would have seen this!

4) I don't beleive I have called anyone dumb or stupid up to this point. All I have tried to do was present some technical information to anyone who wanted to listen. If you don't want to listen, stop reading or shut the f@ck up!

5) Snortguys if you would read all the way through the articles you might get all the information. If as you look from the side of your vehicle and your links are crossed like an X the lower links cause anti-squat because the are angled down. the upper links will cause squat because they are angled up. Now depending on the angles that are choosen you can change the amount of anti-squat the system has.

6) Again for the snort guys, I never said anything about the scorpion and rear steer. What i said was that the angle of his rear link design cuases anti-squat. Whether or not he has a pivot at this point makes no difference. The force he generates while climbing a steep hill will actually twist the frame where his links connect. This is why the vehicle has anti-squat.

7)Snort guys please know what you are talking about before you give a responce. It makes you look a lot smarter.

8)DR.Mud, Sorry I didn't respond till today. I had to go back to the real world for a while and start the new Baja Design. A four link with coil overs would not be a six link because the coilovers do nothing to position the axle, hence the term link. I a leaf spring or "Hotchkis" design the leaf springs are a two link design. The locate the axle from front to back and side to side. I guess I did not understand your original Idea. If I understand you rightnow it seems that you will have shackles on both ends thus eliminating any of the link properties of the leaf spring. If This is true you are correct. In your original design I hadn't understood that there would be shackles on beth end and that they would also rotate. Again here your are correct. The only change in spring rate would be tortional. Since the spring never twists there is no torsion. I still believe for what you are doing the three link or opposing a-arm setup with coils or coil-overs would work much better. I know the cost is a little more but coils aren't that expensive. Anyway I'm glad we can keep our discusion technical and not result to name calling like the snort guys. If there just playing cool! But I'm not trying to bash anyone here.

9)Desertoy, I do not think your design is too complicated at all. If the rear is triangulated as I stated before and you can get the intersecting points of the imaginary lines to be close to equal distances from the groung the street and off-road charateristics shouls be very good. Another way to do this is to use opposing a-arms. Using this method you don't have to calculate the imaginary point because it is a real point. The real point is the point of the A-arm/triangle. Make these two points equal and the arms the same length and you will have little or no rear steer or anti-squat. Here is your responce to Roll axis. Roll axis is a axis which your axle rotates about. On leaf spring vehicles the roll axis is the line made by the two eyes of the spring and then centered on the vehicle. This is the imaginary line the axle will rotate about. If one eye is higher or lower than the other this is what causes rear steer.

Coiled, It makes me happy to see that I at least helped someone understand something. If you were the only one to learn anything I would be happy. But I bet there are a lot of people out there reading and learning and just staying quiet in the back ground happy about all the knowledge they are learning while others bicker about if it is book smarts or actual real world info that anyone could use.

AIRZUKI, I also believe that a limiting strap is a good idea. I doesn't prevent anti-squat though. The more the rear suspension drops the more anti-squat will be present. What I was wanting everyone to under stand is that if you start will little or no anti-squat as the suspension cycles you develope anti-squat and when it is still relatively small it still remains usefull.

Paul G,
It was a great opening comment to get everyone to respond. Look at how many hits this topic has (115) at present. I'm not a dick and I like constructive critisism. Please I envite you to tell me when I am wrong. I am still learning here also.

Donovan, Thanks for the back up. The scorpion is neet to look at but I have seen rigs built much better with less gadgets. Look out!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!, I actually believe the SNORT Guys TJ/Toyota was one of the best rigs I saw at ARCA. Good Job Guys! Back to your question about rear steer. Rear steer is only bad 66.6% of the time. 33.3% of the time you want the rear to steer in a particular direction. 33.3% of the time you want it to go straight and 33.3% you want it to go the other direction it all depends on the situation! This is the reason hydraulic rear steering is becoming so popular, because with this you decide which way you want it to steer.

Nasvik, Sorry you are so close minded. As I said before I have never read any books on the subject. All I have learned is from people who build real world suspensions that kick ass! Sorry I didn't mean to irritate you! <IMG SRC="smilies/biggrin.gif" border="0">

Richie, Do you live in Morro? CALPOLYSTUD=Greg email me if you want me to stop by!

Pig Pen, Did you remember to wipe this morning? How many times are you gonna roll this weekend? I want you to hurry up and break some of that leaf spring suspension off so we can get started on the Four link!
Shitsca=Your mom!:eyemouth

Tin Bender, thanks for keeping all the talk on an educated level! <IMG SRC="smilies/biggrin.gif" border="0">

David Jackson59, I don't know about your rig but Pigs rig would get crushed by mine!
David it seems that you forgot Pig is a (IT/Industrial Technology/I tried to be an engineer) He doesn't have to make excuses for when his stuff fails.

Neckster, Off course the links are not parrallel in the picture if they were there would be severe rear steer. This is an engineered suspension if you look closely that is a 36" Bogger and there is at least that much room between the top of the tire and the fenderwell and there is also over 25 inches of travel. I would say there is very little rear steer for that kind of travel. As far as the links go they are 1-5/8x.25 4130 cromoly DOM. They regularly break rocks with no dammage to the links. Also for your info I have seem this truck drive everything(Moab, The Tank Trap, Johnson Valley) and never use the winch. It is f*cking amazing.

Weasel. Your car did good in the hill climb becuase you had skinny tires that dug down and grabbed the hard pack and nice low gearing!

DR.Mud, Thanks again for your support!

4x4Grrl, The Wrangler I was refering to was sprung under and did not have a problem with axle-wrap that is why I used it as an example. <IMG SRC="smilies/smile.gif" border="0"> I did See Walker Evens climb A-7 and he did not have any trouble with anti-sqaut. This is also a reason he did so well over all. That toy will make a lot of stuff look like childs play.

ElTaco, as I said before my original coments were intended to get people on to the discussion. I am not arrogant and I am not a small cubical engineer. I like to build sh%t. test it, break it, and make it better! If you want to stick to leaf spring that is your buisness. Like I said before as long as were having fun who cares!

Thank you everybody for all the comments. It is great hearing all the ideas. Lets keep them coming. <IMG SRC="smilies/wink.gif" border="0">

Originally posted by DR. Mud:
<STRONG>Exactly why Hummers ROCK off road <IMG SRC="smilies/rolleyes.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0"></STRONG>


A reliable source told me that they are actually pieces of sheot when put to the test. He served in the Desert Storm war. He claimed that the Hummers broke down all the time and those guys were constantly having to fix them.

Ah... so many good thoughts to reply to, amidst the testosterone. This may actually take some formatting and editing work to be coherent... should be fun! <IMG SRC="smilies/biggrin.gif" border="0">
--- SNORTclown said (with a slight Scottish accent, I believe): "On the other thread, you spoke of a slalom issue with flat towing... It's really not an issue, dear sir! The things of which our esteemed engineer friend speaks are true but have nowhere near the severity with which he characterizes them. In 99% of the real world cases, you would never notice then -- nor would they prevent you from going somewhere or killing someone." ...then I'm sure he retired to the shed for a cuppa tea with the Mario brothers. <IMG SRC="smilies/biggrin.gif" border="0"> Just wondering -- anyone ever seen Jackie Stewart and SNORT in the same room at the same time? Twins separated at birth? <IMG SRC="smilies/biggrin.gif" border="0">
Snort, I was suggesting that flat-towing or trailering would prevent these problems from rearing up while driving on the road. Dunno if I was clear... are you saying that your 4x4 would handle tight slaloms well, in spite of the non-textbook geometry?

--- coiled said: "...I used the top link, or A arm, because it is relatively break free, cheap to build, and the only thing that will ever need to be replaced is the rubber radius arm bushings ... To me, that was better than having heim joints that you have to replace every year or run the risk of breaking ... I had to ... buy a couple of tractor heim joint for the other two links, but i only run them at one end up at the t-case and the other end I run bushings. I guess I'm more into not breaking and wheeling..."
Dig the bushing and heim combination -- that allows your linkage to be a little off without tearing itself to pieces and still provides decent NVH dampening.

--- DRM (or whatever he's dubbed himself today) said, in response to my post: Unless you don't attach the axle to the leaf springs (ever seen a drop-away axle? WEIRD), they still locate the axle at least a bit. Quite a bit, in terms of side-to-side, not so much front-to-rear, but still plenty to bind up during extreme travel and break parts.
"Front to back location? Not one Bit"
Ummm... yeah. One bit, within the constraints of the shackle.... at the extremes of travel, you most certainly have fore-aft force vectors coming down from the frame and acting on the axle through the springs and shackle.
A variable-length link, sure -- one that changes as the spring cycles through its arc.
"Wrong answer --- The front half of the leaf spring is a "link" with a working distance of the flat length (measured along the length of the main spring leaf, not "through the air" sistance) from the front eye to the axle. It cannot EVER be longer, but it can be shorter."
I get that -- that's why I called it a 'variable length link' (let's exclude springwrap, which can also change the effective length of this link). What are we arguing, here... looks like we're in agreement (insert standard objection here to agreeing with DRM <IMG SRC="smilies/biggrin.gif" border="0"> ).


--- AIRZUKI said: "Also as a student of the sport of 'wheeling a modified rig , the link suspension information available from "book sources" is not as valuable as the "stud" seems to think it is, roll center, anti-squat, even CG are easy things to quantify if things like traction and speed/acceleration can be predicted, an easy thing to do if the surface you are dealing with is paved.... if the surface is a 20' tall boulder with 2 little flags on it as wide as your track width, and you have only 4 minutes to complete........"
These variables are still worth considering, for road handling, right? BTW, how did your 'Zuk slalom with a one-axled Toyota chained to its bumper after NWRCC? That remains one of the coolest recoveried I've seen -- but I do wonder about the on-highway traits of 7000 pounds, three axles, and 200" of SuzukYota wheelbase. <IMG SRC="smilies/thefinger.gif" border="0">

--- Sam said: Hahahaha.... you just described me FJ. I can't fabricate and I know squat about geometry, but mine actually turned out decent by some standards and great by my own standards. I designed mine to have no rear steer (though I have front link steer, go figure). It works well, but I wouldn't say that it is the answer, only one option."
Sam, I haven't seen your rig yet in person -- how's it handle on pavement? Serious question -- we can all see it kicks AZZ on boulders! <IMG SRC="smilies/cool.gif" border="0">

As for whether that was Kelly or Lance -- clearly it was Kelly. She spells better than Dub Diddy. <IMG SRC="smilies/thefinger.gif" border="0">

Randii (outta breath)

Originally posted by 4x4Grrl:
<STRONG>
A reliable source told me that they are actually pieces of sheot when put to the test. He served in the Desert Storm war. He claimed that the Hummers broke down all the time and those guys were constantly having to fix them.</STRONG>

This is getting off the topic at habd, but IMHO Kelly - I take military personnel's opiniosn of the Hummer with a grain... no - a shaker of salt.

Ever see how people treat a "rental" vehicle? I have a few friends in Desert Storm as well - and I know they regularly took them for joy rides and beat them HARD. That being said - I can see why they think they would fail.

And, having had a friend who had a SWEET Hummer (full leather, in-dash DVD, all the trimmin's) with 38" swampers and was not afraid to seriously GET IT (ever rolled a Hummer? He did <IMG SRC="smilies/wink.gif" border="0"> ) I can say without a doubt that in the right hands, a Hummer can be AWESOME on the trail...

Randii - that was waaayyy to confusing - even for you... but I think I agree with you <IMG SRC="smilies/tongue.gif" border="0">

Originally posted by DR. Mud:
<STRONG>This is getting off the topic at habd, but IMHO Kelly - I take military personnel's opiniosn of the Hummer with a grain... no - a shaker of salt.

Ever see how people treat a "rental" vehicle? I have a few friends in Desert Storm as well - and I know they regularly took them for joy rides and beat them HARD. That being said - I can see why they think they would fail.

And, having had a friend who had a SWEET Hummer (full leather, in-dash DVD, all the trimmin's) with 38" swampers and was not afraid to seriously GET IT (ever rolled a Hummer? He did <IMG SRC="smilies/wink.gif" border="0"> ) I can say without a doubt that in the right hands, a Hummer can be AWESOME on the trail...</STRONG>


HAHAHAHAHAHAHAHAHAHA so.. you take the opinion of the people who the vehicles were designed for, using them for what they were designed for with a shaker of thought? HAHAHAHAHAHAH <IMG SRC="smilies/clown.gif" border="0"> Hate to say it Dave, combat conditions aint exactly a leisurly drive in the country..

Originally posted by DR. Mud:
<STRONG>Hey Lance - you forget to log Kelly off again? <IMG SRC="smilies/tongue.gif" border="0"></STRONG>

Seems to be written in the same style as Kelly usually uses.

Originally posted by mike:
<STRONG>
HAHAHAHAHAHAHAHAHAHA so.. you take the opinion of the people who the vehicles were designed for, using them for what they were designed for with a shaker of thought? HAHAHAHAHAHAH <IMG SRC="smilies/clown.gif" border="0"> Hate to say it Dave, combat conditions aint exactly a leisurly drive in the country..</STRONG>

Mike, they are not designed to be jumped off of 20 foot high dunes like I know many of our service men did in Desert Storm... You know the difference I am talking about - rough service is not the same as abusive "rental car" metality many military Hummer users have...

Originally posted by DR. Mud:
<STRONG>This is getting off the topic at habd, but IMHO Kelly - I take military personnel's opiniosn of the Hummer with a grain... no - a shaker of salt.

And, having had a friend who had a SWEET Hummer (full leather, in-dash DVD, all the trimmin's) with 38" swampers and was not afraid to seriously GET IT (ever rolled a Hummer? He did <IMG SRC="smilies/wink.gif" border="0"> ) I can say without a doubt that in the right hands, a Hummer can be AWESOME on the trail...</STRONG>

I have wheeled with a Hummer and from what I have seen I am not impressed. (sorry Tim if you are reading this <IMG SRC="smilies/wink.gif" border="0">) In my opinion they are out of their element on the trail.

Originally posted by Paul G:
<STRONG>I have wheeled with a Hummer and from what I have seen I am not impressed. (sorry Tim if you are reading this <IMG SRC="smilies/wink.gif" border="0">) In my opinion they are out of their element on the trail.</STRONG>

Not impressed by what - the vehicle? The driver? I have wheeled with several Hummers from time to time, and most of the time the driver is what is holding the vehicle back (maybe something about having $75k in STOCK a vehicle and being scared of the Hummer Dealer repair bill has something to do with that <IMG SRC="smilies/tongue.gif" border="0"> )

Um excuse me those pictures that you posted of your work... that Bronco is mine and you didn't ever work on it. I don't even know you.

Above that are pictures of Dylan's Toyota I don't think you worked on that either. When he first did the 3 link rear suspension he hadn't even come to Cal Poly. He went to 1/4 eliptic for his senior project and I was the one who gave him some advice on anti squat and roll steer to get him started. Now he works for sway away and he redid his links again this time removing the gas tank and starting fresh to get the geometry right.

Lets look at the other vehicles. Steve's dodge on the left I don't think you touched that unless you work at the dodge dealer, then chances are you did. Steves jeep Well you sure hadn't worked on it when I took that picture at open house. He had just bought it from Marvin and it is good old leaf springs anyways. Under that is Brad's jeep and at that time it had 4 inch springs and scary long shackles all around. I don't know what happened to it now, Brad is still at Poly so maybe you have worked on his jeep I'll give you the benefit of the doubt. Under that is Marvin's 1/4 elliptic CJ5 Again senior project, again you had nothing to do with it. Under that is Drew's CJ7 that was a spring over on Wrangler springs at that time, and now it is the tube frame deal that Pig Pen posted pictures of under the Arca Contender topic. It is being built in So cal in Dylan and Drews garage NOT BY YOU. I believe that you probably did actually at least contribute to the rear suspension on the jeep with the rolled on scallops Kevin's? But I don't think you ever worked on Scott's Wrangler. Don't try to take credit for shit you didn't do.

The People that I know who are most knowledgable about offroad suspension are very humble about it. they admit that they don't know much, and that everything is a compromise. Since you don't take this attitude I am going to assume you don't know shit.

Gordon you are correct I never did work on your vehicle, I didn't do much on dylan's either but I learned a lot of pricipals from Dylan and Drews designs . I did work on Marvins a little. I am not trying to take credit for any of these vehichles each of these people built their own susensions. I was trying to show that the principals work not take credit for anyone elses accomplishments! If you read the previous articles I do mention that I do not know everthing and don't claim that I do. Please read carefully. I started this post to get a response and I got it!

Gordon,
By the way we just went down to see Dylan and Drew. Drew, Pigs, and I went to ARCA together. It was a blast. Please don't bash me I'm just trying to get some technical discusion going.

Originally posted by DR. Mud:
<STRONG>Not impressed by what - the vehicle? </STRONG>

That's right. I'm not impressed with the way Hummers perform off road. I'm not impressed with the suspension design. I'm not impressed with the lack of grond clearance for the body. I'm not impressed with the poor visibility out the windows. I'm not impressed with the poor fit and finish. Basically I'm just not impressed with Hummers. I have driven one and though I've never wheeled one myself what I have seen of them off road I just have to ask why smeone would choose one as their 4 wheeler if it was not simply to show off how much money they have.

Even if I had all the money in the world I would not buy one (except maybe to start an off-road touring company so that I can take money from the fools who think Hummers are "THE 4x4").

Originally posted by calpolystud:
<STRONG>Gordon,
By the way we just went down to see Dylan and Drew. Drew, Pigs, and I went to ARCA together. It was a blast. Please don't bash me I'm just trying to get some technical discusion going.</STRONG>


"Please don't bash me..." Why not? You start off telling everyone what a suspension god you are. When asked to prove it you say this "For those of you who want pictures of some of the vehicles that me and my freinds work on here you go." We find out that is 99% bullshit and your just a liar. Now your trying to get out of it by claiming you just wanted to start some suspension dialog and then continue to critique everyone's posts as if what you have to say is gospel.
I'm glad Cal Poly has people like Gordon to balance out the reputation guys like you are giving it.

I think you covered this in a previous post but, what is the importance of the distance between the upper and lower arms at the differential vs. at the frame? Keep in mind driveline (u-joint)angle on a long travel suspension. I would prefer that the pinion points at the output flange of the transfer case throughout the travel, or as close to that as possible.

Originally posted by calpolystud:
<STRONG>

Weasel. Your car did good in the hill climb becuase you had skinny tires that dug down and grabbed the hard pack and nice low gearing!

</STRONG>


This bullshit, our senior car had the exact same tires on it and the same PSI as we did and they didn't even come close to our times. There was lots of other cars that had tires simliar to our as well. It was the four wheel steering that allowed the rear tires to move in and out of the ruts and get traction to the rear wheels. It the same principle that applies to when your stuck or climbing hills you turn the front wheels to get more traction. I would think a smart guy like you would already know this.
Hey Pigpin, don't you guys do any rollover testing? We've flopped our car on it's side about four time testing it, and the senior car did a endo off a hill during testing, two front flips then rolled sideways twice. Something you might want to add for next year.
Hey Erin, sup! Got it running, huh must be nice!

I'm not going to pretend to know anything about this subject, but when this is your sig:
"When you are really ready to find out whats goin on talk to me... ", you are definitely going to rub people the wrong way and come across as an arrogant prick, whether you are one or not. You might be a Hell of a guy, but from my standpoint so far, you are an arrogant prick....JMO

CPS,

It simply amazes me how someone with your obvious education, can say that your not arogant with a signiture and screen name like yours.

You know some of your shit, but your people skills are only rivaled by the fuckin' Unibomber!!

How many times a day do you say "People who think they know everything, really piss off those of us who do!!"??

Originally posted by calpolystud:
<STRONG>Ok, I'm Back!

Let's get some things straight here first!

1) I have never read a book on suspension design!

</STRONG>


What kind of school doesn't let you have textbooks?

Sort of a simple question I guess, but how would you go about getting your links parallel with eachother and yet also with the ground, without sacrificing too much ground clearance? All three of my links point down a tad on level ground, but the only way I could see to combat this would have been to build some insanely tall mount off the pumpkin to make the wish bone top link parallel with the ground yet still have enough room between that and the bottom links to have flexing movement. As for the bottom links with my rear frame being narrowed the way it is I had to kinda bend them inward to avoid hitting the frame while flexing, and I didn't want to put the mounting locations under the frame at the t-case where they are just begging to grab hold of some rocks.

Originally posted by desertoy:
<STRONG> what is the importance of the distance between the upper and lower arms at the differential vs. at the frame? Keep in mind driveline (u-joint)angle on a long travel suspension. I would prefer that the pinion points at the output flange of the transfer case throughout the travel, or as close to that as possible.</STRONG>

DT, if you look at your susp. from the side and extend an imaginary line in space from each link. The point they intersect, is the instantaneous center. This is the point, where the power is theoretically applied to the chassis and it directly affects the amount of antisquat. The further back on the chassis, to more A.S. you have. To get the pinion to rotate up with axle droop, you need to have the upper links longer than the lowers(which tends to be difficult on a rockcrawler). But since your rarely dealing with non articulating droop, it's really not an issue.

Originally posted by calpolystud:
<STRONG>Gordon you are correct I never did work on your vehicle, I didn't do much on dylan's either but I learned a lot of pricipals from Dylan and Drews designs . I did work on Marvins a little. I am not trying to take credit for any of these vehichles each of these people built their own susensions. I was trying to show that the principals work not take credit for anyone elses accomplishments! If you read the previous articles I do mention that I do not know everthing and don't claim that I do. Please read carefully. I started this post to get a response and I got it!</STRONG>

Hey, I saw Jason and Trevor's rigs last weekend...that must make me a King Shit suspension builder too...or would I have to have a picture of the rigs too to absorb all of the knowledge that went in to them?


Just wondering how much actual hands-on it takes to get goD status....

I must admit I have little idea of what is going on throughout this post but it is highly entertaining and this "god" guy seems to be lasting longer than the last.

I've always been timid on this board and I have endlessly read people saying something like "if you don't have thick skin, this board aint the place for you." Why doesn't everyone just thicken their skin a little more...? To me it seems like this guy comes in (I'll grant that calling himself the "GOD OF SUSPENSIONS" is kinda arrogant, but he has explained that he did that only to start a good discussion--touchdown 4 pages in 2 days, is that a POR record??) who most people haven't heard of before and he threatens you (SNORT folks primarily) because he can talk the talk and seems to be able to walk the walk (although I did lose a little trust w/ the shooting down of all his pictures, but let me remind everyone that he did say rigs "me and my friends built." I don't think anyone is arguing that the owners of those rigs are friends of his. And you can flame me all you want, but it seems to me like CalPoly is the only person who knows a damn thing about this topic who is being proactive with this discussion. Everyone else who *might* know something is too busy trying to make him look like an idiot (props to Dr. Mud and the few others who have at least stayed civilized in the discussion). If the SNORT asses ( <IMG SRC="smilies/thefinger.gif" border="0"> you're acting like it!) and everyone else that is guilty of it, would cease the name-calling and accusations, maybe this thread would be that much more helpful to people like me who don't know much about the realm of link suspensions. The only people on this thread who leave me pissed off are those who keep giving this guy a hard ass time. He has said that he didn't mean anything serious by the "GOD OF SUSPENSIONS" thing--he wasn't being arrogant, he was trying to get your attention, and it worked...MOVE ON. He has convinced me that he knows something, so instead of bashing him, bashing engineers, bashing stupid people, smart people, Web Wheelers, etc...how about you offer something to the discussion that is helpful and proactive instead of being a $hithead. Thanks, and <IMG SRC="smilies/thefinger.gif" border="0">

And if you get <IMG SRC="smilies/emb.gif" border="0"> then your skin aint thick enough, according to the general census <IMG SRC="smilies/maggie.gif" border="0">

<IMG SRC="smilies/thefinger.gif" border="0">

<IMG width=512 height=384 SRC="http://www.pirate4x4.com/ubb/uploads/up9.jpg">
This is sort of what the rear end of my suspension looks like so you know what I am talking about

Originally posted by Paul G:
<STRONG>That's right. I'm not impressed with the way Hummers perform off road. I'm not impressed with the suspension design. I'm not impressed with the lack of grond clearance for the body. I'm not impressed with the poor visibility out the windows. I'm not impressed with the poor fit and finish. Basically I'm just not impressed with Hummers. I have driven one and though I've never wheeled one myself what I have seen of them off road I just have to ask why smeone would choose one as their 4 wheeler if it was not simply to show off how much money they have.

Even if I had all the money in the world I would not buy one (except maybe to start an off-road touring company so that I can take money from the fools who think Hummers are "THE 4x4").</STRONG>

Ha, ok, I'll play in this thread for a bit since the Hummer came up. Yes Paul I read your post. No. I'm not offended. <IMG SRC="smilies/smile.gif" border="0">

Yes I have extensively wheeled Hummers in various terrain including rocks, mud, hills and water.

Here's their some pluses and minuses:

1. They are heavy. Along with a long wheelbase and wide body, they tend to be adequate performers in deep mud at best.

2. They are excellent on hills and sidehills because of their wide stance, geared hubs and diesel engine.

3. They perform well in off camber situations even though they have ultra stiff suspensions (RTI about 450).

Paul of course is entitled to his opinion, because the last time he went offroading 3 years ago, his mostly stock Explorer with Thornbirds only had to be towed 2 or 3 times by the Humvee anyway. <IMG SRC="smilies/smile.gif" border="0">

My Hummer makes an excellent tow truck for my other offroad vehicle though. <IMG SRC="smilies/smile.gif" border="0">

Originally posted by 1982 CJ-7:
<STRONG>I've always been timid on this board and I have endlessly read people saying something like "if you don't have thick skin, this board aint the place for you." Why doesn't everyone just thicken their skin a little more...? To me it seems like this guy comes in (I'll grant that calling himself the "GOD OF SUSPENSIONS" is kinda arrogant, but he has explained that he did that only to start a good discussion--touchdown 4 pages in 2 days, is that a POR record??) who most people haven't heard of before and he threatens you (SNORT folks primarily) because he can talk the talk and seems to be able to walk the walk (although I did lose a little trust w/ the shooting down of all his pictures, but let me remind everyone that he did say rigs "me and my friends built." I don't think anyone is arguing that the owners of those rigs are friends of his. And you can flame me all you want, but it seems to me like CalPoly is the only person who knows a damn thing about this topic who is being proactive with this discussion. Everyone else who *might* know something is too busy trying to make him look like an idiot (props to Dr. Mud and the few others who have at least stayed civilized in the discussion). If the SNORT asses ( <IMG SRC="smilies/thefinger.gif" border="0"> you're acting like it!) and everyone else that is guilty of it, would cease the name-calling and accusations, maybe this thread would be that much more helpful to people like me who don't know much about the realm of link suspensions. The only people on this thread who leave me pissed off are those who keep giving this guy a hard ass time. He has said that he didn't mean anything serious by the "GOD OF SUSPENSIONS" thing--he wasn't being arrogant, he was trying to get your attention, and it worked...MOVE ON. He has convinced me that he knows something, so instead of bashing him, bashing engineers, bashing stupid people, smart people, Web Wheelers, etc...how about you offer something to the discussion that is helpful and proactive instead of being a $hithead. Thanks, and <IMG SRC="smilies/thefinger.gif" border="0">

And if you get <IMG SRC="smilies/emb.gif" border="0"> then your skin aint thick enough, according to the general census <IMG SRC="smilies/maggie.gif" border="0">

<IMG SRC="smilies/thefinger.gif" border="0"></STRONG>


Then you are ready to believe anyone if they claim to be an expert. Great, I'm god of all stock's and bond's, I took economics in colledge send me $1000.
What, you need proof, no problem, I saw Bill Gates once and drank coffee at Starbucks. Now send me the loot. <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by FearMe:
<STRONG>
I saw Bill Gates once and drank coffee at Starbucks. Now send me the loot. <IMG SRC="smilies/biggrin.gif" border="0"></STRONG>

You didn't leave you adress!! Where am I supposed to send the money? I'll just send it to calpolystud and he can forward it to you. You guys are friends... right? <IMG SRC="smilies/wink.gif" border="0">

Originally posted by 1982 CJ-7:
<STRONG>I've always been timid on this board and I have endlessly read people saying something like "if you don't have thick skin, this board aint the place for you." Why doesn't everyone just thicken their skin a little more...? To me it seems like this guy comes in (I'll grant that calling himself the "GOD OF SUSPENSIONS" is kinda arrogant, but he has explained that he did that only to start a good discussion--touchdown 4 pages in 2 days, is that a POR record??) who most people haven't heard of before and he threatens you (SNORT folks primarily) because he can talk the talk and seems to be able to walk the walk (although I did lose a little trust w/ the shooting down of all his pictures, but let me remind everyone that he did say rigs "me and my friends built." I don't think anyone is arguing that the owners of those rigs are friends of his. And you can flame me all you want, but it seems to me like CalPoly is the only person who knows a damn thing about this topic who is being proactive with this discussion. Everyone else who *might* know something is too busy trying to make him look like an idiot (props to Dr. Mud and the few others who have at least stayed civilized in the discussion). If the SNORT asses ( <IMG SRC="smilies/thefinger.gif" border="0"> you're acting like it!) and everyone else that is guilty of it, would cease the name-calling and accusations, maybe this thread would be that much more helpful to people like me who don't know much about the realm of link suspensions. The only people on this thread who leave me pissed off are those who keep giving this guy a hard ass time. He has said that he didn't mean anything serious by the "GOD OF SUSPENSIONS" thing--he wasn't being arrogant, he was trying to get your attention, and it worked...MOVE ON. He has convinced me that he knows something, so instead of bashing him, bashing engineers, bashing stupid people, smart people, Web Wheelers, etc...how about you offer something to the discussion that is helpful and proactive instead of being a $hithead. Thanks, and <IMG SRC="smilies/thefinger.gif" border="0">

And if you get <IMG SRC="smilies/emb.gif" border="0"> then your skin aint thick enough, according to the general census <IMG SRC="smilies/maggie.gif" border="0">

<IMG SRC="smilies/thefinger.gif" border="0"></STRONG>

Alrighty then... here it is in a nut shell for you. When doing a 4 link design, the longer the link bar (to a degree) the better. But try not to sacrifice ground clearance and have it way too long. Second, you don't want your links parallel to each other, but I don't feel you need them to be in an X either (from a side view).Third, (IMO) triangulated upper links seems to work out the best all around for on and off road use. The main thing to remember here is that damn near ANYTHING will work. Take a look around at all the different setups used by people on this board alone. It is damn near impossible to fawk it up. I don't have the perfect setup on my rig, and have never claimed to either. Mine was the first one that we did years ago, and I haven't got around to changing it cause it works good enough. My links are low, long, beat to holy hell, but still function just fine. Sure I can drag them over rocks all day long without having to winch, but it gets old after awhile. I have also put about 20,000 miles on mine on the street, and I have wheeled from Morningside tough truck comp. in Canada, to the hammers, and I've flat towed it a couple of times to the rubicon and back.
My point is, Calpolystud posted some neat facts about doing a linked axle, but for the average guy just out to have some fun in his rig, it doesn't have to be as complicated as one might think.

FearMe:
CalPoly's only offering free information, not a service for a fee. There's a difference...Is that a goat on wheels?? <IMG SRC="smilies/thefinger.gif" border="0">

Question for Ummmmmm GOD

How do both rear wheels traveling at the same rate affect rear steer????? (being Locked up)

wouldn't it create more rear steer than if the diff had a ARB that could be turned off to counter act this effect???????

PS I dont care if the thing does cartwheels under there, if you GET IT then it wont really matter. Build it-Know it- Get it

If you figure this out you can wheel w/2" shackles and make trails look easy <IMG SRC="smilies/biggrin.gif" border="0">

BTW dont ask not to be bashed like a 3 year old <IMG SRC="smilies/thefinger.gif" border="0">
You wanted attention YOU GOT IT
you stepped over the line try'n to come off like the Suspension BADASS and got called on
Live w/it
next time only post pics of stuff you really built (I have met Sony Honneger, maybe I can post a pic and say I built the Scorpion)

Originally posted by 1982 CJ-7:
<STRONG>FearMe:
CalPoly's only offering free information, not a service for a fee. There's a difference...Is that a goat on wheels?? <IMG SRC="smilies/thefinger.gif" border="0"></STRONG>


Ok then, I'm the god of everything you ever wanted to know. Goat on wheel's, why yes, yes it is. But only an Aggie can tell you what they do with goats on wheels back <IMG SRC="smilies/thefinger.gif" border="0">at ya.

Originally posted by calpolystud:
<STRONG>

7)Snort guys please know what you are talking about before you give a responce. It makes you look a lot smarter.

</STRONG>


I'm sorry if you feel that we don't know what we are talking about, and that we apparently look dumb to you. However, if you look at the vehicles we build (which most people on this board have) speaks for our knowledge in the real world. I have no doubt of your booksmarts (or acquired knowledge as you put it), but if you could put up some pics of something that YOU have done, maybe you would gain some credibility with the masses.

"You won't hurt my feelings!" .... I sure hope you meant that.
<IMG SRC="smilies/thefinger.gif" border="0">

oh yeah two words about applied theory when building a rig <IMG SRC="smilies/thefinger.gif" border="0">

BIG IRON LOL LOL LOL

that was the best engineered POS ever built

I'll take the SNORTcrews real world built 1/4 4 link anyday, over that CAL POLY GOD OF SUSPENSION BS anyday

btw no hard feelings <IMG SRC="smilies/clown.gif" border="0"> just apply my .02 to the side that thinks you are a WEB WHEELIN PUNK KID

side note
If you know so damn much about everything why did you buy a 84 4runner???????
if you dont understand why I ask such a question feel free to ask and I'll tell you why
<IMG SRC="smilies/flipoff.gif" border="0">

Oh fawk now you got Frosty started..........Me thinks rear steer Fully Gets It! <IMG SRC="smilies/biggrin.gif" border="0"> Ask Lance about his rig during the CNC 2001 <IMG SRC="smilies/wink.gif" border="0">

Originally posted by Kevin:
<STRONG>Oh fawk now you got Frosty started..........Me thinks rear steer Fully Gets It! <IMG SRC="smilies/biggrin.gif" border="0"> Ask Lance about his rig during the CNC 2001 <IMG SRC="smilies/wink.gif" border="0"></STRONG>

Lance was fully being hampered by his apperantly incorrectly engineered rear suspension, I really feel sorry for him having to live w/a bad design like that

Poor guy

<IMG SRC="smilies/rolleyes.gif" border="0">

maybe he should take some classes at Cal Poly and figure out how to fix that mess <IMG SRC="smilies/thefinger.gif" border="0">

LOL......you coming to the reception this weekend?

--- Donovan said: "... Why is rear steer bad? We are not doing 120 mph. Why are you guys so worried about it?"
Because I drive my junk to the trail -- and back. That's Sacramento to Moab, Sacramento to Denver, Sacramento to Phoenix... you get the idea. My junk needs to be able to fly down the road at 80mph, take twisty mountain roads, etc... and not steer itself into the ditch. Some rigs I have seen on the trail have sufficient body roll and travelled-out rear stear to make me nervous.

--- Weasel said: "...as for the suspension being different on a Baja then a rockcrawler, this is true but the same principles still apply and if you can build a kick ass baja suspesion then I highly doubt you'll have any problems with a rock crawler suspension."
Ummm... so long-travel IFS is what I should use in the rocks? <IMG SRC="smilies/rolleyes.gif" border="0"> Dem's apples and oranges, son. <IMG SRC="smilies/biggrin.gif" border="0">

--- calpolystud said: "...If I understand you rightnow it seems that you will have shackles on both ends thus eliminating any of the link properties of the leaf spring."
I still disagree with this -- I've seen one bind enough to break parts on a ramp. Great theory, poor reality. Heck, it didn't even work on a RAMP!

--- Neckster said: "The main thing to remember here is that damn near ANYTHING will work. Take a look around at all the different setups used by people on this board alone. It is damn near impossible to fawk it up."
See above abortive tale of dual-shackle four-link ramp failure. Wow do I disagree that 'It is damn near impossible to fawk it up'... unless you specify that the vehicle is intended for TRAIL ONLY use... and I guess I've still seen some linked-abominations rolling around the trails... IMHO, planning is critical if you want it to work in a wide range of situations - PLEASE don't just try to 'get lucky' with your links...

Thanks for starting a kick-azz thread, calpolystud... you can certainly talk the talk. Welcome... let's see the walk...

Randii

Originally posted by Kevin:
<STRONG>LOL......you coming to the reception this weekend?</STRONG>No I cant

<IMG SRC="smilies/mad.gif" border="0">

I have to be Best man in my best mans Wedding sat

cant even go after the bridesmaids

[ 07-18-2001: Message edited by: frosty4x ]

Lance was fully being hampered... Poor guy!
Kelly can console him... and apparently, redesign his suspension!

Or at the very least, revalve his shocks, lube his spherical rod ends, and re-align his linkage. <IMG SRC="smilies/biggrin.gif" border="0">

Whattawoman!

Randii

Damnit Jim! We'll be thinking of ya while we're partyin! I'll talk to ya.

I'll say one thing for this board...You guys are relentless bastids when you smell blood. : )
Anyway...how many of you have tried dbl.Vee links with no panhard and how did it work-out ?
I've been running it for a while with coilovers and It seems to be doing real good as long as the links and joints are stout.

[ 07-18-2001: Message edited by: dirtrod ]

YA know following all these posts ( I got a late start lol ) I have to smile some. It is rather interesting to see the way everyone is extreamly interested in learning, and of course the banter and assorted other stuff is always enlightining as well...lol

I was just thinking with all the techno jargon and such floating around, and what I have learned in past aboyut suspensions etc. I look at my friends Ford with front and rear coiled 4 links (F-350) and I realize that I am sure none of this was overly easy to aquire info 10+ years ago when it was built. And then to think it still is extreamly well balanced and works great for it's application is rather amazing. Then looking back at Top TRuck 98 when he competed against the Scorpion and others I was amazed at where technolgy has gone in our wheeling rigs..and yet again now it has made another huge jump forward. But I like his old rig...still works awesum and is super simple. So maybe huge travel links are not the answer for the type of terrain I encouter. Still kinda like my old leafs.. but I am learning what I can on the subject incase I get ambition and rip some moly outa the rafters here and build something to satisfy my curiosity.
Carry on techo wheelers.

Originally posted by randii:
<STRONG>Sam said: Hahahaha.... you just described me FJ. I can't fabricate and I know squat about geometry, but mine actually turned out decent by some standards and great by my own standards. I designed mine to have no rear steer (though I have front link steer, go figure). It works well, but I wouldn't say that it is the answer, only one option."
Sam, I haven't seen your rig yet in person -- how's it handle on pavement? Serious question -- we can all see it kicks AZZ on boulders! <IMG SRC="smilies/cool.gif" border="0">

Randii (outta breath)</STRONG>

Hey Randy(ii) - Yeah, missed you at the Rubicon this year. I wasn't walking this time if you can believe it. It handles like crap on the cement(not really, but definitely not a daily driver for sure). I have only had it up to 35 maybe 40 mph. I am sure I could go faster, but due to the axle walk of the front and ultra soft springs, I don't feel like pushing it any further. Don't need to either really since I pretty much only crawl it. It did get looks though when cruising through town. All I can say about the rig barring any technical talk is that it is fun. The girlfriend likes it and so do I so that is all that matters out on the trail for me. It was a bonus though to have people asking so many questions about it.

-Sam

Originally posted by randii:
Weasel[/b] said: "...as for the suspension being different on a Baja then a rockcrawler, this is true but the same principles still apply and if you can build a kick ass baja suspesion then I highly doubt you'll have any problems with a rock crawler suspension."
Ummm... so long-travel IFS is what I should use in the rocks? <IMG SRC="smilies/rolleyes.gif" border="0"> Dem's apples and oranges, son. <IMG SRC="smilies/biggrin.gif" border="0">



I never said that IFS should be used in rocks, but I imagine that the stuff you learned to built a IFS you can use for a rock suspension. I don't know cause I've just finshed my only halfway through school, but I know the most of the seniors that did our car wouldn't have any problem building a suspension for crawling. In fact a couple have cralwers and they can use the same knowledge on there rigs as well as our IFS baja car.

calpolystud aka the god of suspension, step aside the goats are here, just kidding, we dont have time sit at the computer, we should be in the garage working on the jeep/trophy truck, i'll post some pics soon.

gordon, you are the man, i just read your reply on pg.4, if anyone is the god of offroad suspension design, it would be Brian Kudela and he doesnt give a shit about rockcrawling, and the second god of offroad suspension design would be Gordon, that was some funny shit, you taught us alot, we bow down.

[QUOTE]Originally posted by randii:
[QB]Ah... so many good thoughts to reply to, amidst the testosterone. This may actually take some formatting and editing work to be coherent... should be fun
--- AIRZUKI said: "Also as a student of the sport of 'wheeling a modified rig , the link suspension information available from "book sources" is not as valuable as the "stud" seems to think it is, roll center, anti-squat, even CG are easy things to quantify if things like traction and speed/acceleration can be predicted, an easy thing to do if the surface you are dealing with is paved.... if the surface is a 20' tall boulder with 2 little flags on it as wide as your track width, and you have only 4 minutes to complete........"
These variables are still worth considering, for road handling, right? BTW, how did your 'Zuk slalom with a one-axled Toyota chained to its bumper after NWRCC? That remains one of the coolest recoveried I've seen -- but I do wonder about the on-highway traits of 7000 pounds, three axles, and 200" of SuzukYota wheelbase. <IMG SRC="smilies/thefinger.gif" border="0">

Well I can't say it was the smoothest ride I've ever had, but DAMN when Richard breaks stuff he goes all out! <IMG SRC="smilies/biggrin.gif" border="0">
as far as the highway traits....... I felt I was lucky just to get him to the pavement!
( I made the mistake of leaving my license plate on and his truck wadded it up like a beer can ) the really funny thing was I only had front drive at the time ( both rear axleshafts had broken by this time, man that course was unforgiving...) poor little D44 dragging our broken junk outta there....

as far as CG , roll center etc.. in terms of on road handling... perhaps it is more important....... that being said Bags allow you to adjust your ride height and lower your CG or vastly improved on-road handling
( I could take any on or off ramp at 50mph without fear....)
<IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

Dang it Frosty, all you SNORT's, others - I am <IMG SRC="smilies/crybaby2.gif" border="0"> <IMG SRC="smilies/crybaby2.gif" border="0"> <IMG SRC="smilies/crybaby2.gif" border="0"> out for suspension help here and you guys just seem to be interested in comparing penis size <IMG SRC="smilies/rolleyes.gif" border="0">

Come AWN!!!! if I am not arguing, you know you shouldn't be either <IMG SRC="smilies/tongue.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0">

These variables are still worth considering, for road handling, right? BTW, how did your 'Zuk slalom with a one-axled Toyota chained to its bumper after NWRCC? That remains one of the coolest recoveried I've seen -- but I do wonder about the on-highway traits of 7000 pounds, three axles, and 200" of SuzukYota wheelbase. <IMG SRC="smilies/thefinger.gif" border="0">
Well I can't say it was the smoothest ride I've ever had, but DAMN when Richard breaks stuff he goes all out! <IMG SRC="smilies/biggrin.gif" border="0">
Sure does... snapped the whole freaking knuckle offa that 44!

as far as CG , roll center etc.. in terms of on road handling... perhaps it is more important....... that being said Bags allow you to adjust your ride height and lower your CG or vastly improved on-road handling
( I could take any on or off ramp at 50mph without fear....) <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">
Awesome... ever considered AutoX-ing that Zook? <IMG SRC="smilies/biggrin.gif" border="0">

Randii

Originally posted by WOLF359:
<STRONG>
Paul of course is entitled to his opinion, because the last time he went offroading 3 years ago, his mostly stock Explorer with Thornbirds only had to be towed 2 or 3 times by the Humvee anyway. <IMG SRC="smilies/smile.gif" border="0">
</STRONG>

LOL <IMG SRC="smilies/csmile.gif" border="0"> I think there are pictures out there that show the opposite situation Tim. <IMG SRC="smilies/biggrin.gif" border="0">




My Hummer makes an excellent tow truck for my other offroad vehicle though.

I can respect that because your regular wheeler is a Cruiser you obviously see the limitations of using a Hummer off road. <IMG SRC="smilies/eyemouth.gif" border="0">

But back to the subject at hand... Have you run out to your garage and checked to see if your Cruiser's suspension meet the specifications outlined by CalMoldySpud? <IMG SRC="smilies/question.gif" border="0"> <IMG SRC="smilies/question.gif" border="0">

[ 07-18-2001: Message edited by: Paul G ]

OK, I went throught ALL 5 PAGES of this thread and took out all of the most informative statements. Here they are:

------------------------------------------First when designing a link type suspension for off-road use you must consider: Anti-Squat, Roll axis, Link length, and Link angle.
Anti-Squat is a property that determiners how much the rear will raise or lower when accelerating.
The steeper the angle of the links (assuming they are parallel) the greater the Anti-Squat.

Rear steer is a property that is determined by roll-axis.

A little Anti-Squat is good because it increases the force placed on the tire.

In the case of two parrallel links parallel with the ground, when the vehichle is at ride hight there is no anti-squat caused by the links. Intertia of the center of gravity will actually cause the rear to squat in this particular case, as the vehicle accelerates.

What this means to rock crawlers is get your links as flat as possible.

If your lower link has a steep angle then an upper link with an angle exactly the same with a slope up toward the rear of the vehichle instead of the front like the lower links will have exactly the opposite verticle force component. What all this mean is that if your links are crossed like an X from the side profile your anti-sqaut should not be apperant.
Another way to accomplish the same results is to have both links as parrallel to the ground as possible. Of course this changes your roll axis which causes rear steer

there is no perfect solution only an iterative process of finding the least amount of unwanted properties.

Mounting point locations have a lot to do with roll axis. But another consideration is the angle of the link as you look at them from a top view. These are the determining factors of the roll axis.

If properly designed a 1/4 eliptic front could be done. The problem is that the front experiences greater side loads than the rear when cornering. What this means is that for the same vehichle a properly designed front 1/4 eliptic must be stronger than the rear. Space is usually the biggest problem though. To run a 1/4 eliptic without a panhard rod the links must have the correct geometry. This usually involves triangulated links under the oil pan and front drive shaft usually there is no enough clearance. So what end up happening is four parralell links in combination with a panhard rod which could make it hard for the 1/4 eliptic springs to fit. Thats why it is common to see a 4 link/panhard rod/coil spring setup.

If you were to run imaginary lines extending from the end of your links to the point where they cross this is the first defining point of your roll axis. When you triangulate both set of links the roll axis becomes the line between the two imaginary points. What I am getting at is that you need to have these two imaginary points the same distance or as close as possible from the ground. If the roll

Originally posted by frosty4x:
<STRONG>

If you figure this out you can wheel w/2" shackles and make trails look easy <IMG SRC="smilies/biggrin.gif" border="0">

</STRONG>


*sobbing* Awwwwwww, I think I'm gonna cry..... *deep breath*

If you thought 2"shackles were cool wait till you see my NEW 4" CHROME shackles!!!
ARCA here I come...... <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by DR. Mud:
<STRONG>Dang it Frosty, all you SNORT's, others - I am <IMG SRC="smilies/crybaby2.gif" border="0"> <IMG SRC="smilies/crybaby2.gif" border="0"> <IMG SRC="smilies/crybaby2.gif" border="0"> out for suspension help here and you guys just seem to be interested in comparing penis size <IMG SRC="smilies/rolleyes.gif" border="0">

Come AWN!!!! if I am not arguing, you know you shouldn't be either <IMG SRC="smilies/tongue.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0"></STRONG>

DRM, the best way for you to handle your suspension, IMO, is to do a four link with your dual shackle with your current springs (if they are giving you the ride height and quality of ride that you want). With the four link, you will definately have no need for a panhard bar, and you most definately not have any axle wrap. Even though Randii has seen ONE not work in the past, I have seen and done several that work great. SNORTclown's truck had that exact same thing for about 3 years. If you were to do a search, I'm sure that you could find some pics of it. Also, the only complaint Jason ever had, was once in awhile he would get the front side shackle hung up on stuff. Not enough to stop him, but enough to iritate him. Before he went 1/4 eliptic, he was just going to inboard his springs to allow the shackle to be up higher, but he didn't end up doing that (obviously).



Oh, and Randii...... it scored about 1500 on a 25 degree ramp <IMG SRC="smilies/thefinger.gif" border="0">

Originally posted by Snowball:
<STRONG>You dont need links with IFS BABY!!!
IFS RULES !! <IMG SRC="smilies/thefinger.gif" border="0"> <IMG SRC="smilies/thefinger.gif" border="0"> <IMG SRC="smilies/thefinger.gif" border="0"></STRONG>

bwhahahahahaahah!! You get 'em Mike. I'll come over this weekend to help you put IFS in your Bronco <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

Not to confuse the issue even more, but don't forget that as a linked type suspension cycles, many if not all (on some styles) of the determining points move, changing the geometry drastically.

A good example of this is Sam's SA (double A arms) If you calculate the roll axis at rest, it's at a fairly extreme angle, but as one side stuffs and the other droops, The rear pivot point levels out and there is no rear steer. If you look at the picture below, you can see the upper and lower a-arm pivot points, almost level, at full twist. http://www.sierrarockcrawlers.com/images2/0905.jpg

you can also see the front roll steer, which is just a fairly standard 4 link. Most of the rollsteer could be tuned out of the front, but it's really not worth the effort.

The double Aarm setup with some minor springrate tuning and a disconnectable swaybar is as close to the "best of both worlds" type setup, I've seen yet. Very good clearance, level rollaxis and close to correct antisquat. But as with any extreme
articulation suspension, without limiting and controling chassis sway, it would be death on the road at high speed.

Originally posted by goat1:
<STRONG>gordon, you are the man, i just read your reply on pg.4, if anyone is the god of offroad suspension design, it would be Brian Kudela and he doesnt give a shit about rockcrawling, and the second god of offroad suspension design would be Gordon, that was some funny shit, you taught us alot, we bow down.</STRONG>

That would be Dylan the guy with the black Yota. He is being modest. Those guys (Drew and Dylan) know their shit, they passed me up a long time ago.

O.K. I have been read this thread through, took about an hour. And I just had too add my comments.

Just to qualify this I have not built a link designed suspension for off road only for drag use, but with all my wheelin experience I will give my humble observations, and yes I have serveral book smarts which I rarely use(Degree in Automotive Engineering Technology and ASE Master Tech.)

A discussion of anti-squat and suspension is interesting, I have dissuced and researched it several dozens times over the past year, but I have to disagree with some of your premisses calploy.

First anti-roll is fine to take into consideration to counter-act acceleration weight transfer, but to base much of it for wheeling I think is going down the wrong path. The reason you sighted was from the A-7 obstical at the ARCA event. I wasn't there but from the description the obstical was a very steep uphill climb. This is where the anti-squat premise fails. It has to do with weight transfer. Anti-squat for drag racing is a funtion of ther realtion the link intersection has in relation to the angle drawn from the Hieght of the Center of gravity(CG) over the front tire to the contact point of the rear tire. The closer the interection of the force extended from the rear link to the hieght of CG the more anti-squat. In the case you sighted though, and in most wheeling siuations the vehcile is not moving on a flat plane, in you example climbing uphill. The CG is now acting on the vehicle in a totaly different dirction without change to the force from the links. This is why you could not build in a correct anti-squat for that situation.

Second, Ant piont about a limiting stap on the center of the axle is a good thing in this uphill scenario, because it is preventing the suspenion form unloading causing the vehicles weight to be tranfered away from the hill. This may not affect your Anti-squat calculations, but it certainly affects weight transfer which is excatly what anti-squat is trying to counteract. That is why it relates, and if you need real world check the pic to the left, My rig unload because I don't have a strap to prevent unloading of the suspension in these situations which is bad and causes tippy and endo concerns. I will be doing this to my rig to better balance uphill and downhill suspension unloading, centered on the axle to prevent limiting axle travel.

Third, roll center is something good to take into account, but you have to look at in in realation to the CG hieght. becuase the body roll around the roll center is directly dependant on that. You could have the perfect parrallel roll center you talking about, but if the distance between the hieght of the rollcenter and the hieght of the center of gravity is great (ie, a tall rig) the vehicle(body) will tend to roll much easier around this roll center.

Fourth the snort crowd and others are completly correct about parrallel links parrallel to the ground is not real world wheeling. You will drag and hang up on the mounts and links all day, which makes a terrible trail rig. Plus if I visualize it in my mind the pinion angle of the axle remains at a constant with parrallel equal length bars causing in extreme travel the drive shaft unjoint to bind. With proper lengths and angles you nac get the pinion going up in droop and down in compression to lessen the working angle of the ujiont. I am not certain if that setup would be benifical for other factors but should be considered due to the travel in offroad suspension.

Also the comments on the scorpion are way off base. If you have ever seen that design, and I have in person, the axles are solidly mounted to the links. there is no way for that thing to "rear steer". I am not going into you'll have to just think about it for a while and take a look at the design of the scorpion.

Lastly I really think that attention in link and trail rig design should be focused on creating travel that doesn't bind, keeping the pinion in the right place through all travel, keeping the links out of harms way, and make a rig that is weighted 50/50 with suspension that limits unloading and resists floping on offcamber situations, and keep the vehicle light without hurting durablilty.

Those are my humble comments, I am no expert, but I have wheeled long enough to have truck designs always on my mind. Any comments or challenges welcome.

But really Calpoly you should come out and say your knowledge comes from some book reading, I know some of mine has, besides I don't know anyone who has learned that leaf spring suspensions are of "Hotchkiss" design that didn't get that from a book and suspension desing. My source for that tid bit was "Chassis Engineering by Herb Adams" pg. 36,67-69. What was yours? <IMG SRC="smilies/tongue.gif" border="0">

[ 07-18-2001: Message edited by: cruiserrg ]

Just one thing to add here - I do not like "50/50 balanced" suspensions...

I prefer to have one end flex better than the other - more like 65/35 - and like the predictability that gives.

For example, I would guess my truck is about 65/35 with much more flex up front. Set up like this - I know the front will droop a tire waaaay down, but the truck will tend to remain level with the rear axle until you transfer enough weight forward as you drove down the obstacle.

If you had 50/50 balance there - out of 10 trips down the same obstacle, you may lean down with the front suspension half the time, and the other half the time you may not..

Does that make sense to anyone else? <IMG SRC="smilies/confused.gif" border="0">

I have some links, <IMG SRC="smilies/thefinger.gif" border="0"> <IMG SRC="smilies/thefinger.gif" border="0"> what do you think?

Originally posted by cruiserrg:
<STRONG>O.K. I have been read this thread through, took about an hour. And I just had too add my comments.

Just to qualify this I have not built a link designed suspension for off road only for drag use, but with all my wheelin experience I will give my humble observations, and yes I have serveral book smarts which I rarely use(Degree in Automotive Engineering Technology and ASE Master Tech.)

A discussion of anti-squat and suspension is interesting, I have dissuced and researched it several dozens times over the past year, but I have to disagree with some of your premisses calploy.

First anti-roll is fine to take into consideration to counter-act acceleration weight transfer, but to base much of it for wheeling I think is going down the wrong path. The reason you sighted was from the A-7 obstical at the ARCA event. I wasn't there but from the description the obstical was a very steep uphill climb. This is where the anti-squat premise fails. It has to do with weight transfer. Anti-squat for drag racing is a funtion of ther realtion the link intersection has in relation to the angle drawn from the Hieght of the Center of gravity(CG) over the front tire to the contact point of the rear tire. The closer the interection of the force extended from the rear link to the hieght of CG the more anti-squat. In the case you sighted though, and in most wheeling siuations the vehcile is not moving on a flat plane, in you example climbing uphill. The CG is now acting on the vehicle in a totaly different dirction without change to the force from the links. This is why you could not build in a correct anti-squat for that situation.

Second, Ant piont about a limiting stap on the center of the axle is a good thing in this uphill scenario, because it is preventing the suspenion form unloading causing the vehicles weight to be tranfered away from the hill. This may not affect your Anti-squat calculations, but it certainly affects weight transfer which is excatly what anti-squat is trying to counteract. That is why it relates, and if you need real world check the pic to the left, My rig unload because I don't have a strap to prevent unloading of the suspension in these situations which is bad and causes tippy and endo concerns. I will be doing this to my rig to better balance uphill and downhill suspension unloading, centered on the axle to prevent limiting axle travel.

Third, roll center is something good to take into account, but you have to look at in in realation to the CG hieght. becuase the body roll around the roll center is directly dependant on that. You could have the perfect parrallel roll center you talking about, but if the distance between the hieght of the rollcenter and the hieght of the center of gravity is great (ie, a tall rig) the vehicle(body) will tend to roll much easier around this roll center.

Fourth the snort crowd and others are completly correct about parrallel links parrallel to the ground is not real world wheeling. You will drag and hang up on the mounts and links all day, which makes a terrible trail rig. Plus if I visualize it in my mind the pinion angle of the axle remains at a constant with parrallel equal length bars causing in extreme travel the drive shaft unjoint to bind. With proper lengths and angles you nac get the pinion going up in droop and down in compression to lessen the working angle of the ujiont. I am not certain if that setup would be benifical for other factors but should be considered due to the travel in offroad suspension.

Also the comments on the scorpion are way off base. If you have ever seen that design, and I have in person, the axles are solidly mounted to the links. there is no way for that thing to "rear steer". I am not going into you'll have to just think about it for a while and take a look at the design of the scorpion.

Lastly I really think that attention in link and trail rig design should be focused on creating travel that doesn't bind, keeping the pinion in the right place through all travel, keeping the links out of harms way, and make a rig that is weighted 50/50 with suspension that limits unloading and resists floping on offcamber situations, and keep the vehicle light without hurting durablilty.

Those are my humble comments, I am no expert, but I have wheeled long enough to have truck designs always on my mind. Any comments or challenges welcome.

But really Calpoly you should come out and say your knowledge comes from some book reading, I know some of mine has, besides I don't know anyone who has learned that leaf spring suspensions are of "Hotchkiss" design that didn't get that from a book and suspension desing. My source for that tid bit was "Chassis Engineering by Herb Adams" pg. 36,67-69. What was yours? <IMG SRC="smilies/tongue.gif" border="0">

[ 07-18-2001: Message edited by: cruiserrg ]</STRONG>

Well written! Nice to see someone taking into account all the factors of wheeling and not just trying to figure out link Geometry to make it work well in the parking lot heading for a ramp. FINALLY a book I enjoyed reading! <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/smokin.gif" border="0">

.O.K. I have been read this thread through, took about an hour. And I just had too add my comments.
Just to qualify this I have not built a link designed suspension for off road only for drag use, but with all my wheelin experience I will give my humble observations, and yes I have serveral book smarts which I rarely use(Degree in Automotive Engineering Technology and ASE Master Tech.)

A discussion of anti-squat and suspension is interesting, I have dissuced and researched it several dozens times over the past year, but I have to disagree with some of your premisses calploy.

First anti-roll is fine to take into consideration to counter-act acceleration weight transfer, but to base much of it for wheeling I think is going down the wrong path. The reason you sighted was from the A-7 obstical at the ARCA event. I wasn't there but from the description the obstical was a very steep uphill climb. This is where the anti-squat premise fails. It has to do with weight transfer. Anti-squat for drag racing is a funtion of ther realtion the link intersection has in relation to the angle drawn from the Hieght of the Center of gravity(CG) over the front tire to the contact point of the rear tire. The closer the interection of the force extended from the rear link to the hieght of CG the more anti-squat. In the case you sighted though, and in most wheeling siuations the vehcile is not moving on a flat plane, in you example climbing uphill. The CG is now acting on the vehicle in a totaly different dirction without change to the force from the links. This is why you could not build in a correct anti-squat for that situation


Response,
In most situations involving rock crawling acceleration is way less than in drag racing. Therefore the CG has less to do with anti-squat than the link angle. The link angle is much greater on a rock crawling suspension, thus the force driving the rear of the vehichle up is also much greater relative to the amount of force being applied. This causes the mass of the vehicle to have an inertial propety away from the rock suface. In the case of a steep obsticle, The inertia tends to pull the vehicle away from the rock and loose traction.


Second, Ant piont about a limiting stap on the center of the axle is a good thing in this uphill scenario, because it is preventing the suspenion form unloading causing the vehicles weight to be tranfered away from the hill. This may not affect your Anti-squat calculations, but it certainly affects weight transfer which is excatly what anti-squat is trying to counteract. That is why it relates, and if you need real world check the pic to the left, My rig unload because I don't have a strap to prevent unloading of the suspension in these situations which is bad and causes tippy and endo concerns. I will be doing this to my rig to better balance uphill and downhill suspension unloading, centered on the axle to prevent limiting axle travel.


Response,
As I already said a limiting strap is a good idea, I just said it would not change the anti-squat properties. Unless the vehicle is at full droop you will still experience problems with anti-squat.

Third, roll center is something good to take into account, but you have to look at in in realation to the CG hieght. becuase the body roll around the roll center is directly dependant on that. You could have the perfect parrallel roll center you talking about, but if the distance between the hieght of the rollcenter and the hieght of the center of gravity is great (ie, a tall rig) the vehicle(body) will tend to roll much easier around this roll center.


Response,
You are correct, But there is not much a lifted rig can do about the distance between the roll center and the roll axis except put the links as high as possible. The only way to combat it is to use sway bars, but then you loose articulation.


Fourth the snort crowd and others are completly correct about parrallel links parrallel to the ground is not real world wheeling. You will drag and hang up on the mounts and links all day, which makes a terrible trail rig. Plus if I visualize it in my mind the pinion angle of the axle remains at a constant with parrallel equal length bars causing in extreme travel the drive shaft unjoint to bind. With proper lengths and angles you nac get the pinion going up in droop and down in compression to lessen the working angle of the ujiont. I am not certain if that setup would be benifical for other factors but should be considered due to the travel in offroad suspension.

Response,
I never said parallel links were the way to go I used them as an example so that people could understand the properties of anti-squat. In my opinion the links (as view from the side of the vehicle) should look somthing like an X. But this is not always true either. The important thing is that the roll axis is as close to parallel with the ground as possible.


Also the comments on the scorpion are way off base. If you have ever seen that design, and I have in person, the axles are solidly mounted to the links. there is no way for that thing to "rear steer". I am not going into you'll have to just think about it for a while and take a look at the design of the scorpion.


Responce,
If you read what is said again I never talked about the scorpion and rear steer, I talked about the scorpion and anti-squat. The SNORT guy got that all mixed up!


Lastly I really think that attention in link and trail rig design should be focused on creating travel that doesn't bind, keeping the pinion in the right place through all travel, keeping the links out of harms way, and make a rig that is weighted 50/50 with suspension that limits unloading and resists floping on offcamber situations, and keep the vehicle light without hurting durablilty.


Response,
I agree!


Those are my humble comments, I am no expert, but I have wheeled long enough to have truck designs always on my mind. Any comments or challenges welcome.

But really Calpoly you should come out and say your knowledge comes from some book reading, I know some of mine has, besides I don't know anyone who has learned that leaf spring suspensions are of "Hotchkiss" design that didn't get that from a book and suspension desing. My source for that tid bit was "Chassis Engineering by Herb Adams" pg. 36,67-69. What was yours?

Response,
The web is a wonderfull place to learn all kinds of things if you know were to look. I will be taking a ground vehicle dynamics class soon and hopefully learn even more. Then I will say I learned some of it from a book, but until then my friends and the web combined with information from knowledgeable people have given me a good foundation from where to start. Watching and observing people on the trail is probley the best place to see what really works! But it is also the best place to help you understand why all the principals I have talked about work or don't. Beside all the chassis engineering books I have ever seen are about race cars. I don't care about race cars!

Thank you for your edjucated reponse. It is nice to actually talk with someone who understands what I am talking about. Please post a responce and correct me if you think I am wrong!

Originally posted by DR. Mud:
<STRONG>Yeah - and what's with that? <IMG SRC="smilies/confused.gif" border="0"> *I* am supposed to be the one ranting and raving off topic with personal attack slurs... If even *I* am not doing that, some of these guys should stop and wonder <IMG SRC="smilies/eek.gif" border="0"> <IMG SRC="smilies/tongue.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"></STRONG>

I have!!!
HAHAH j/k....

Originally posted by calpolystud:
<STRONG>.
(Degree in Automotive Engineering Technology and ASE Master Tech.)


!</STRONG>

Hmm, been a service tech for close to 14 years now, hate to say it, but have met some of the dumbest ASE MASTER TECHS ever... All ya got to do is read a book to pass them, and no, this is an experiance call...

As for all the link data/info, i prefer somebody who has gone thru the stages of building/learning, can learn more that way than any book can teach you.....

Crash,
Cruiserrg wrote that not me, make sure you read everything before you make yourself look like an ass!

I have an easy question for you suspension gurus. This will be my first attempt at making an a-arm/wishbone to control axle wrap for my lowly soa CJ7, and I would like to do it up right the first time. I was thinking a heim joint above the pumpkin, I have also seen one where they used a Ford radius arm bushing at the pumpkin end. What joint/bushing should I use for the ones that go above the spring eye, and are these suppose to go directly above the spring eye inboard of the frame. And lastly what diameter of tubing should I use. Thanks, and even though this is all above my head I still like reading it.

CJBoxer,
If your only hope is to control axle wrap with this link, make it simple, Maybe spring eye bushings on one end and a Heim on the other. The length shood be close to the length between your spring eye and the axle. The part that is on the frame shood sit at or around the same height as the spring eye and the other somewhere above the axle. This will cause the least binding in my opinion since the link and the leafspring will follow the same arc. Of course this is no perfect solution since the leaf is not a constant length link. Experiment with mounting location see it you like one over the other etc.


For everybody on the list,

I will be gone for a couple of days but I will reply to as many people as possible when I get back! Have fun on the Con Pigs! and wipe yourself you stink!

Originally posted by CJBoxer:
<STRONG>I have an easy question for you suspension gurus. This will be my first attempt at making an a-arm/wishbone to control axle wrap for my lowly soa CJ7, and I would like to do it up right the first time. I was thinking a heim joint above the pumpkin, I have also seen one where they used a Ford radius arm bushing at the pumpkin end. What joint/bushing should I use for the ones that go above the spring eye, and are these suppose to go directly above the spring eye inboard of the frame. And lastly what diameter of tubing should I use. Thanks, and even though this is all above my head I still like reading it.</STRONG>


I am far from a suspension guru, but I have tried the wishbone method on leafspring suspension to combat axle wrap and had problems with it binding on articulation. It actually ripped the mount off of the inside of the frame after about a year.
The way to go to get rid of axle wrap on leaf spring suspension is a single laddar bar, close to the centar of the axle housing going foreward to a shackle mounted to the x-member.
It worked great with no binding.

Desertoy,

check your email!

Oh my ! The cat is out of the bag (again)...

If you put in a link such as calpollywolly just recomended, there won't be any wrap-up...or suspension movement either.
Hmmm...

Originally posted by desertoy:
<STRONG>
I am far from a suspension guru, but I have tried the wishbone method on leafspring suspension to combat axle wrap and had problems with it binding on articulation. It actually ripped the mount off of the inside of the frame after about a year.
The way to go to get rid of axle wrap on leaf spring suspension is a single laddar bar, close to the centar of the axle housing going foreward to a shackle mounted to the x-member.
It worked great with no binding.</STRONG>


I agree with the shackle mounting. But I had lousy results with a single bar, it did nothing but leverage axle wrap. On the other hand with an A arm I have had no wrap.. I have, however, tore the mount off the axle.

Originally posted by calpolystud:
<STRONG>*snip* you make yourself look like an ass!</STRONG>

LOL! You would know calpolylimpdick! <IMG SRC="smilies/thefinger.gif" border="0">

That's the first thing you have said here I know is from your personal experiance.

Too bad your people skills are 180 out from your technical skills (yet to be verified IMHO).

Originally posted by dirtrod:
<STRONG>Oh my ! The cat is out of the bag (again)...

If you put in a link such as calpollywolly just recomended, there won't be any wrap-up...or suspension movement either.
Hmmm...</STRONG>

Care to explain yourself in why that would be.

CJBoxer

Unless you go with double shackles your axle needs to move back and forth (with leaves), If you mount the ends of the rod to the axle and frame without allowing for that fore/aft movement, you will either bind the axle in place, or pull the mounts off either end...

I learned that one (the hard way) back in the 80s... : )

steveh,

I have not ever used this approach, I was going for something that wouldn't bind, who knows it may, but at least I said something usefull, not a backstabbing comment! I personally use high damping rate shocks in line with the leaf spring to control axle wrap. They stop the wrap but not the travel!

Unfortunatley CPS "kickershocks" no matter how firmly damped, will only work to reduce axle wrap under certain situations, and lowgeared, hightorque, rockcrawling is not one of those occasions.

I really liked the dbl. shackle with a hiem jointed 4-link (V-link on the pig), the springs seemed to flex alot easier when both ends are free.
I have a bud running a single bar with a swinging mount at the front and single spring shackles, and he loves it.

Patman your right but I am running a 4cylinder with leafsprings=no problem!

Originally posted by desertoy (he was summarizing the good stuff):
Anti-Squat is a property that determiners how much the rear will raise or lower when accelerating.
Close -- squat and antisquat derive from the same factors, but act in opposite direction. Squat generally lowers that end of the vehicle. Anti-squat generally raises that end of the vehicle.

Randii

Unless you go with double shackles your axle needs to move back and forth (with leaves), If you mount the ends of the rod to the axle and frame without allowing for that fore/aft movement, you will either bind the axle in place, or pull the mounts off either end...
I have seen this solution work, and work well... but you have to find the 'sweet spot' in the arcs where the bar binds as little as possible... and it helps to have compliant link ends (like bushings). The spring changes effective length as it cycles.

Mount it in the wrong place and it will tear out... I've done that twice. Mount it at the right place and it MAY work, but I have a set of s-shaped springs that show the evidence of that failing, too... the link stayed fine, but the axle pivoted where it met the link (the bar) and the spring flexed/unflexed madly as the wheels hopped. One weekend in Moab and the springs were shot....

In the end, I like the ladder-bar-with-shackle. It's just easier -- and more permissive to misalignment (even leaf springs rear-steer at the travel extreme) and minimal binding.

All that said, plenty of Toyota guys use a single link... and textbook, it shouldn't work, but it often does. What's that say?

DEPENDS ON THE VEHICLE, THE ANGLES, THE SPRINGS -- basically, the SYSTEM.

...and maybe the alignment of the moon, and the number of stickers on the links. For rice racers, stickers make you go faster... for rock crawlers, stickers make your suspension flex. <IMG SRC="smilies/biggrin.gif" border="0">

Randii

Originally posted by calpolystud:
<STRONG>steveh,

I have not ever used this approach, I was going for something that wouldn't bind, who knows it may, but at least I said something usefull, not a backstabbing comment! I personally use high damping rate shocks in line with the leaf spring to control axle wrap. They stop the wrap but not the travel!</STRONG>

What steveh wrote:
Originally posted by steveh :
<STRONG>
LOL! You would know calpolylimpdick!

That's the first thing you have said here I know is from your personal experiance.

Too bad your people skills are 180 out from your technical skills (yet to be verified IMHO).
</STRONG>

Let me clarify:

I am the one who called you an ass to your face, therefore how is this a backstab? <IMG SRC="smilies/thefinger.gif" border="0">

Just because you run a 4cyl with leaf springs doesn't give you the right to give out bad information. I used to run a small 64 Hp stock engine in my Sami. With geared T-case and axles I had enough to twist leaf springs off every day. Kicker shock dampen axle wrap, they don't eliminate it. I would go with the single ladder bar, hiem and shackle approach. Didn't bind at all on my rig, and she twists up priety good. <IMG SRC="smilies/jeep1.gif" border="0">

CalPoly, try to ignore SheveH - as far as I can tell he likes to jump into threads about midway through and start attacking the person it looks like everyone else is dogging (did someone say Sheeple?). He offeres ZERO information here, so treat his comments as such...

So....

Back to my questions about the single V link (with the point of the V on the Tcase end) and standard leaf springs with a shackle at each end...

I see that the V link would control forward/rearward location of the axle - so that covers that aspect.

And I think if the mounts are done the right way, the single V link combined with the leaf sprinsg and a shackle at each end would control lateral axle movement enough as well (again, a panhard bar could always be added later if needed).

But What I cannot figure is whethere or not thwere would be axle wrap issues...

A quick picture...
<IMG width=600 height=344 SRC="http://www.pirate4x4.com/ubb/uploads/linktest01.jpg">

Again, ignoring lateral movement of the axle, and knowing that the V link would properly locate the axle forward/backward of the truck, I keep wondering if this setup would want to wrap up the axle BAD.

As you can see with the blue and red lines (representing possible link locations) would it be best to mount the links to the front of the axle tube (at it's centerline parallel with the ground), or below the axle tube centerline?

My guess is mounting it parallel with the ground in front of the tube would be best...

Also - the axle end of the links would be need some attention to control wrap as well. The axle end mounts would be poly bushings in a tube type mount for added rigidity. If these bushings were paralle to the axle tube, I can see where it would want to wrap up, but I would suggest mounting the bushings in line with the links, so they would be angled in towards the center of the V up at the Tcase (about 30* I would guess). Angled like this should also help keep the axle from wrapping up.

Sooooo.... any thoughts on whether the axle would wrap up? I fear it would pivot at the V link bushings at the axle tube, one shackle would fold back, the othe shackle would fold inward, and the spring would want to "S" really bad... Agree? Disagree?

Here you go David.......did you ever see these??
http://bbs.off-road.com/wwwthreads_uploads/51-453980-bigredramp2.jpg
http://bbs.off-road.com/wwwthreads_uploads/51-453983-bigredramp3.jpg

Originally posted by DR. Mud:
<STRONG>Sooooo.... any thoughts on whether the axle would wrap up? I fear it would pivot at the V link bushings at the axle tube, one shackle would fold back, the othe shackle would fold inward, and the spring would want to "S" really bad... Agree? Disagree?</STRONG>

David this is exactly what would happen. This design would actualy wrap more and easier than the leafs by themselves, since you remove the solid front spring mount, and add a solid pivot point for the axle to leverage off of.

The only thing keeping this design from wrapping is the the leaf spring itself. If you want to keep your leafsprings, go with a "Sam's OffRoad" style arm or double shackle and a 4 or 3 link.

Here's a couple more close ups:
http://users.erols.com/piranha/rear1.JPG
http://users.erols.com/piranha/rear2.JPG
HTH <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

DRM, if you used a ford-style C-bushing on the axle, then it would work fine for you--or if you made each leg of the "V-link" a ladder bar, so it mounts to the axle with two bushings, then it would work fine for you.

If you're still skeptical, then make the front-side shackle use the stock spring hanger, that way it's completely reversible if you don't like how it works.

Originally posted by Patman:
<STRONG>David this is exactly what would happen. This design would actualy wrap more and easier than the leafs by themselves, since you remove the solid front spring mount, and add a solid pivot point for the axle to leverage off of. </STRONG>

Ok... so a single top link just above the point of the V (above the driveshaft too of course) and down to the diff would fix that, correct?

Originally posted by I Lean:
<STRONG>DRM, if you used a ford-style C-bushing on the axle, then it would work fine for you--or if you made each leg of the "V-link" a ladder bar, so it mounts to the axle with two bushings, then it would work fine for you.

If you're still skeptical, then make the front-side shackle use the stock spring hanger, that way it's completely reversible if you don't like how it works.</STRONG>

I was considering the "laddar bar" mount at the axle with two bushings (one at the axle centerline, one slightly above) but that gets back to one of my original concerns, about this type of link wanting to "lift" the vehicle up Where the V mounts to the frame...

But you say you have seen something similar work - so I amy try it <IMG SRC="smilies/smile.gif" border="0">

Again, the reversability of keeping the stock leaves is what I had in mind all along - in case it just plain didn't work <IMG SRC="smilies/wink.gif" border="0">

Originally posted by calpolystud:
<STRONG>Crash,
Cruiserrg wrote that not me, make sure you read everything before you make yourself look like an ass!</STRONG>

Hmm, why didn't you put what somebody else said in QUOTES then?? your the ass, not me, impression i got you wrote it, if i made a mistake my bad, but for the records, did I adress that to you?? read it again and shut your cake hole before you answer or be a dick...

Originally posted by calpolystud:
<STRONG>Patman your right but I am running a 4cylinder with leafsprings=no problem!</STRONG>
Did you design it yourself?


What would a 4 cylinder have to do with it?
the kicker shock doesnt work no matter what is pushing it.

Originally posted by DR. Mud:
<STRONG>Ok... so a single top link just above the point of the V (above the driveshaft too of course) and down to the diff would fix that, correct?</STRONG>

Yes it would, but remember that the point at which the upper and lower links intersect in space (Instantaneous center) is where the power is applied to the chassis. If you use a cbushing at the axle end, this point IS the chassis mount.

David if you are going to bother with making links. Just build a four link with ¼ elliptical. It will work much better.

Also 2 Ford C-bushings on an axle will suck. No matter how you mount them.
That is what I was talking about when I said dont go there.

Originally posted by Patman:
<STRONG>Yes it would, but remember that the point at which the upper and lower links intersect in space (Instantaneous center) is where the power is applied to the chassis. If you use a cbushing at the axle end, this point IS the chassis mount.</STRONG>

So the single top link, as long as the point of intersect was waaay out in front of the vehicle somwehere, the issue would be moot...

As for 1/4 eliptical - yesy it works better, but go back & see my comments about cost and easy of building...

I was having some birth day cake with fulleflext and dave_jackson59 last night and calpolystud's thread just came up. Ended up talking about this dude for the next 30 min. Next thing you know this guy is a celeberty??? SHOW YOUR SELF Calpolystud!!!!!

Is this guy Sorta/ Lil John under a new name!

Too much time on your hands boy!

Get out and wheel!!!!! <IMG SRC="smilies/puke.gif" border="0"> <IMG SRC="smilies/puke.gif" border="0"> <IMG SRC="smilies/puke.gif" border="0"> <IMG SRC="smilies/puke.gif" border="0"> <IMG SRC="smilies/puke.gif" border="0"> <IMG SRC="smilies/puke.gif" border="0"> <IMG SRC="smilies/puke.gif" border="0"> <IMG SRC="smilies/puke.gif" border="0">

Originally posted by cruiserrg:
<STRONG>.

Second, Ant point about a limiting stap on the center of the axle is a good thing in this uphill scenario, because it is preventing the suspenion form unloading causing the vehicles weight to be tranfered away from the hill. This may not affect your Anti-squat calculations, but it certainly affects weight transfer which is excatly what anti-squat is trying to counteract. That is why it relates, and if you need real world check the pic to the left, My rig unload because I don't have a strap to prevent unloading of the suspension in these situations which is bad and causes tippy and endo concerns. I will be doing this to my rig to better balance uphill and downhill suspension unloading, centered on the axle to prevent limiting axle travel.

Lastly I really think that attention in link and trail rig design should be focused on creating travel that doesn't bind, keeping the pinion in the right place through all travel, keeping the links out of harms way, and make a rig that is weighted 50/50 with suspension that limits unloading and resists floping on offcamber situations, and keep the vehicle light without hurting durablilty.

</STRONG>

I'm glad someone understands what I'm talking about, thank you!! As the STUD said it does not dictate Anti-squat, but it keeps it under control!!! Thats what I was getting at, I like the anti-squat, its just you have to strap it to keep it under control in certain situations.

<IMG SRC="smilies/bounce.gif" border="0">

Good comments about no-bind, good pinion location and links that are high and tight.

Those WERE the 3 major things I considered when I built my rear suspension, Anti-squat, roll-center and rear steer were all secondary thing I considered. I would suggest to anyone starting a four link for the first time to go with bind, pinion and clearance primarily first. If you can acheive good anti-squat, roll-center and rear steer later, that is bonus points!!

DRM Wrote: that he like 65/35 ratio front to rear, I have to agree with that in the aspect when climbing things the rear see's the entire weight of the vehicle and needs to be stiffer, but thats a whole differnt thread!!

Dr. Mud, Looking and reading your design for a ladderbar mount with double shakled leaf springs is a good start, but from what I gleamed from it the ladder bar would be mounted to the center(or near center) of the axle. I think by not having links that go toward the outside ends of the axle it may tend to "dog walk" becuase there is not solid mount to control the axle from going forward or back at the ends. I may be misunderstanding the desing you describe so correct me if I am wrong.
If you look at covertiyota's pics there are two lower arms going to the axle ends which look angled slightly to keep the axle centered and an upper link to control the wrap. I would look more to something like that for a double shakled leaf srung setup. Oh and for 50/50 weight bias I like it when is close to that for me because I see a ton of steep climbs with just as hairy decents. I hate the front coming over my rig climbing about as much as I hate the a** end coming over going down. But a quick go pedal fixes that.

Cjboxer, I agree as the others do that a ladder type axle-wrap eliminator with a shakle at the front end is the right way to go. I run this on my srung over rig and works well. The closer it is to the center of the axle the less it will limit articulation. There is a good write up on one at
IH8MUD.COM (http://www.ih8mud.com)
under landcruiser tech. If the top mount is above the axle centerline and the lower on is below it will limit axle wrap great, and the lower one can be placed real close to center to keep from hanging up on stuff.

Crash, I hear what you are saying about Master Techs, I go into GM dealers to fix Service PCs and there are a lot of good and a lot of bad ones just like anything else. I just wanted to set a baseline for the knowledge I'm working from. Also yes I have not built a link systems on my own rig, I plan to with my next rig. I have helped a friend fix a poor link system design on his truck, I find some people just have a hard time visualizing all the arcs that the links and axle can travel in. The design I helped him fix caused terrible axle twist and wouldn't caused the suspenssion to bind almost instantly. But you are right experience is invaluable.

Agian only my humble opinons.

Watt?? I mean Watt linkage? Is there a reason that nobody uses a watt linkage instead of a panhard bar? God suggested a 4 link in the front with a panhard bar. How about a 4 link using a watt? How about a pure 3 link in the rear, using a watt on the upper link? How about rotating the watt linkage 90 deg. so it won't limit any articulation?

This is a good thread, almost as good as an earlier one when I learned about Sam's SA setup!

So watt the?

Originally posted by calpolystud:
<STRONG>
Response,
In most situations involving rock crawling acceleration is way less than in drag racing. Therefore the CG has less to do with anti-squat than the link angle. The link angle is much greater on a rock crawling suspension, thus the force driving the rear of the vehichle up is also much greater relative to the amount of force being applied. This causes the mass of the vehicle to have an inertial propety away from the rock suface. In the case of a steep obsticle, The inertia tends to pull the vehicle away from the rock and loose traction.

Response,
You are correct, But there is not much a lifted rig can do about the distance between the roll center and the roll axis except put the links as high as possible. The only way to combat it is to use sway bars, but then you loose articulation.

Response,
I never said parallel links were the way to go I used them as an example so that people could understand the properties of anti-squat. In my opinion the links (as view from the side of the vehicle) should look somthing like an X. But this is not always true either. The important thing is that the roll axis is as close to parallel with the ground as possible.

Responce,
If you read what is said again I never talked about the scorpion and rear steer, I talked about the scorpion and anti-squat. The SNORT guy got that all mixed up!

Response,
I agree!

Response,
The web is a wonderfull place to learn all kinds of things if you know were to look. I will be taking a ground vehicle dynamics class soon and hopefully learn even more. Then I will say I learned some of it from a book, but until then my friends and the web combined with information from knowledgeable people have given me a good foundation from where to start. Watching and observing people on the trail is probley the best place to see what really works! But it is also the best place to help you understand why all the principals I have talked about work or don't. Beside all the chassis engineering books I have ever seen are about race cars. I don't care about race cars!

Thank you for your edjucated reponse. It is nice to actually talk with someone who understands what I am talking about. Please post a responce and correct me if you think I am wrong!</STRONG>

Calpoly,
Here are my thoughts to you reply:

First, the premise I believe you started with to talk about anti-squat was a steep climb that some vehciles (scorpion) wouldn't make where a leaf sprungunder jeep would. I believe you discussed that due to the anti-squat the at the rear axle of the scorpion was bouncing to gain traction. I belive that the concern your desribing is more to the fact that the softer susspenon and air setup on the scorp isn't able to provide a large down force on the tires. IMHO the lever arm the airbag works on in the rear of the scorion isn't long enough to provide sufficent downforce from the tires to ground. The design of the scorpion does a good job to transmitt the articluation force from one side to the other. I feel that in that situation the leaf spring vehicles where providing more downforce from the tire to ground, not due to the anti-squat but the leafs.
Like I mentioned in my previos post climbing hills suspensions lose traction more because of suspension unloading due to weight transfer, more so than any link systems could over come.

Second, as far as the limit strap is concerned, you have to think of it mounted in the center of the axle. If its placed there you don't have to set it to full droop. Think about it how often are both wheels off the gorund in rockcrwaling. You can set the centered limit strap to for example 3-4" to limit suspenision unloading, but it won't affect articulation that much becuse its center mounted. So you the can affect weight transfer, which is what you try to do with anti-squat.

Third, I disagree that there is nothing a trail rig can do about roll center and axis because of there hieght. IIRC roll center is a function of the hight the axle locating links are placed. In a pan-hard bar application it is the hieght which the panhard is mounted. In a splayed fourlink, it is the hieght the angled links are placed on the axle. These things are not constant, especially with the angled four link or three link. So you can affect this by mounting above or below the axle centerline, it may not be much, but it can be built in. And yes sway bars are bad, but proper attention to sring rate and type, can greatly help this and prevent unloading, compair captured coils to uncaptures coils in terms of resistance to body roll.

Forth, you discription of an x link system viewed from the side to me doesn't seem real world. I take this disgin to mean the front mounting of the top link is lower than lower link. If so you would have to mount these link sufficently apart as to not contact during axle articulation, the links would move toward the each other as the axle rotates about its center. This would be with a true four link with straight bars. It could be avoided with a splayed four link. But the other thing to consider is the axle pinion angle change would be exagerated under this condition. because the links travel in arc and are crossed so one is pushing the axle back while the other pushes forward, and since they are on opisite sides of the axle horizontal centerline the axle twists turing the pinion up or down, yes in the right direction but far greater twist than conventional mounting. This would probably bind the ujoints.

Fifth, I am glad we agree on something!

Lastly, yes the web and books are great educational tools, but like everyone here has been saying real world and experience are everything. If you really think that you have a good design, build a scale mock up of the design with the poper attention the trim hieghts and driveshaft ujiont angle limits, hiem joint working angles, and pinion angle. That way you can see what the disgin might do or don't do. But no matter how much you test or design remeber that it will never be right out of the box, everything has to be adjusted and tweeked.

As always these are my humble opinions. I like the discussion, but you must admit you started off on the wrong foot. <IMG SRC="smilies/wink.gif" border="0">

Originally posted by dorfs:
<STRONG>Watt?? I mean Watt linkage? Is there a reason that nobody uses a watt linkage instead of a panhard bar? God suggested a 4 link in the front with a panhard bar. How about a 4 link using a watt? How about a pure 3 link in the rear, using a watt on the upper link? How about rotating the watt linkage 90 deg. so it won't limit any articulation?

This is a good thread, almost as good as an earlier one when I learned about Sam's SA setup!

So watt the?</STRONG>

Dorfs, My uderstanding of a Watts link is a device that rotated around the center of the axle with bars going to oppisite sides of the frame. If this is what you mean, in my opinion it wouldn't work. the mounts for the frame would have to be close to the centerlin of the axle. Serious clearance problems, and travel would be limited when the shorter links of the watts would max out and hold the axle up.
But I think you are talking about something differnt, so provide a better description.
<IMG SRC="smilies/smile.gif" border="0">

[ 07-19-2001: Message edited by: cruiserrg ]

I guess something like the rear of a P/T cruiser, but rotated up to the top of the diff. That way the mounts wouldn't be in the way. This will allow full articulation, and keep the diff centered.

Originally posted by dorfs:
<STRONG>I guess something like the rear of a P/T cruiser, but rotated up to the top of the diff. That way the mounts wouldn't be in the way. This will allow full articulation, and keep the diff centered.</STRONG>

I found a pic of the PT's rear suspension and we are talking about the same thing. I still think you could have trouble with the lower portion of the rotating device getting hung up on stuff. The distance teh links are apart would have to be great to allow more travel of the axle up and down. If it is rotated to run horizontally on the top of the axle the hiems would be at max angle before rotating the center pivot which would wreck the hiems quickly. I think I would stick to a more simplistic design, I alway try to keep things simple for the trial. Less to fix when it breaks. <IMG SRC="smilies/tongue.gif" border="0">

Keep the heims vertical.

After reading all six very interesting pages of this thread here are a few things that have not been talked about:

1)Adjustabilty. I think one of the most important things you can do in your design is to make it adjustable. That way you can tune for your driving style and the conditions you encounter. You dont see many drag race link suspensions that are not adjustable, so why not froadin suspensions?

2)Percentage of Rise. This is something important to consider (more so for drag racing than wheelin, but still important) as too much weight transfer due to link angle will lead to having a light frontend when you probably do not want it to be.

3. Sway bars. I know they can limit flex, but a small diameter bar mounted with the right length arms can add some needed roll stiffness and allow the use of a little softer spring. And if you experiment a little, you can dial in just enough roll stiffness that you can force the front axle to do a little more work to help strive toward a more 50/50 balanced suspension (or for those that dont want 50/50, dial it to what ever you want). The Currie antirock is a good idea to help balance out the TJ, and I think that a rear mounted bar would be beneficial for most link rear suspensions.

Until recently noone has used link suspensions for more than to go fast and straight(drag racing), going fast and turning on a dime(circle burners and road racers), or going fast with lots of wheel travel(desert racing and monster trucks). None of these sports are really worried about how much articulation they have, in fact a few probably want to limit it. So we are left with a lot of theory and experimentation to do. I have read a few of the books mentioned, as well as a few that were not and what I have concluded is that they pretty much leave us with nothing more than a few basic properties to consider as we design our suspensions. You just have to remember that everything is a compromise and that you need to decide what you want early on and build for that. You can have your cake and eat it too, ya just need to know what kind of cake ya want.

[ 07-19-2001: Message edited by: Blackjack ]

Originally posted by Blackjack:
<STRONG> ... So we are left with a lot of theory and experimentation to do. I have read a few of the books mentioned, as well as a few that were not and what I have concluded is that they pretty much leave us with nothing more than a few basic properties to consider as we design our suspensions. You just have to remember that everything is a compromise and that you need to decide what you want early on and build for that. You can have your cake and eat it too, ya just need to know what kind of cake ya want.
</STRONG>

That pretty much sums it up, Blackjack. Whatever works for the individual is, by default, a good design.

will someone explain what a panhard is? <IMG SRC="smilies/question.gif" border="0">

I think that we are all missing something on building rear or front link systems for wheeling. Please answer me some questions. Why does a leaf spring work better on cliffs and ledges than a link setup most times? A leaf spring has a shorter linkage point than a normal linkage type suspension right? So what does a leaf do different than a coil spring or a 1/4 eliptical setup? I think I have the answer but I would like to see what you guys come up with.

Originally posted by troutbum:
<STRONG>will someone explain what a panhard is? <IMG SRC="smilies/question.gif" border="0"></STRONG>

A bar that keeps the axle from moving side to side. They mount on the axle and then on the frame:

-----------0
|
0------------------------------0

Sorry for the crude ACSI art! The top part is the panhard bar (the 0 where it mounts to the frame), the bottom part is the axle with the 0's as the wheels <IMG SRC="smilies/smile.gif" border="0">

Damn it!!! I looks correct when I typed it but it is moved over to the side now - arg!
The top part should be moved over to the right a little.

[ 07-20-2001: Message edited by: long dong rector ]

Originally posted by troutbum:
<STRONG>will someone explain what a panhard is? <IMG SRC="smilies/question.gif" border="0"></STRONG>

A "panhard bar" is the technical term for a track bar, like what comes stock on a TJ or EB or XJ,ZJ etc. in the front.

Basically just a very simple link that locates the axle side to side.

Ok screw that ASCI stuff - here's mspaint!:

<IMG width=512 height=384 SRC="http://www.pirate4x4.com/ubb/uploads/panhard.jpg">

Originally posted by long dong rector:
<STRONG>Ok screw that ASCI stuff - here's mspaint!:

<IMG width=512 height=384 SRC="http://www.pirate4x4.com/ubb/uploads/panhard.jpg"></STRONG>


Picasso??.......is that you?!?! <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">

<IMG width=871 height=505 SRC="http://www.pirate4x4.com/ubb/uploads/test1.gif">

I put this in another post a long time ago I can't find it in the search feature though. Someone else can explain what all the lines mean, there are enough "experts" here.

I just don't understand why you guys go to all the trouble of a dual shackle setup, what a waist.. Remember back in the days with jason ran his, talk about a cluster of stuff, and lots of stuff to hang up on, like neck had said.... Plus you can't increase your departure angle, heck, if you are going links for the dual shackle, toss a set of coils under the thing..

Originally posted by Gordon:
<STRONG><IMG width=871 height=505 SRC="http://www.pirate4x4.com/ubb/uploads/test1.gif">

I put this in another post a long time ago I can't find it in the search feature though. Someone else can explain what all the lines mean, there are enough "experts" here.</STRONG>

Sure looks familiar....Damn, I've seen almost that exact same thing somewhere. Wish I could remember where it was, looks like it would work pretty good, but then I'm not an engineering student. <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by Donovan:
<STRONG>I think that we are all missing something on building rear or front link systems for wheeling. Please answer me some questions. Why does a leaf spring work better on cliffs and ledges than a link setup most times? A leaf spring has a shorter linkage point than a normal linkage type suspension right? So what does a leaf do different than a coil spring or a 1/4 eliptical setup? I think I have the answer but I would like to see what you guys come up with.</STRONG>

One reason could be the length of your arms, and the angle they operate. The front of a leaf spring is basically an arm, and it is relatively short and somewhat flat(unless you run high arch springs). This produces a low percentage of rise which does not transfer as much weight off of the front axle(ie making the front end light) compared to the longer links of a multi link setup. You can tune some of this out by changing the instant center, but then you will have to compromise on something else(this has a lot to do with the lower links angle, the flatter it is can help but you lose ground clearance).

Originally posted by Blackjack:
<STRONG>One reason could be the length of your arms, and the angle they operate. The front of a leaf spring is basically an arm, and it is relatively short and somewhat flat(unless you run high arch springs). This produces a low percentage of rise which does not transfer as much weight off of the front axle(ie making the front end light) compared to the longer links of a multi link setup. You can tune some of this out by changing the instant center, but then you will have to compromise on something else(this has a lot to do with the lower links angle, the flatter it is can help but you lose ground clearance).</STRONG>

With a leaf spring your instant center is way back compared to a link type setup. So your rear should lift really hard under accelertion, shouldn't it in theroy. But they didn't lift that hard.

Originally posted by calpolystud:
<STRONG>
AirBag, You are correct! Anti-squat is a big killer when it comes to climbing steep angles. On flat crawling i.e. Rubicon, The anti-squat doesn't hurt you as much. The mounting points on the frame and axle don't have as much to do with anti-squat as the angle of the link and the link length. Anti-Squat is caused be the vector sum of the forces in the verticle direction. Verticle force vectors become larger when the link angle is increased. </STRONG>

I haven't read all this, but I am gonna pipe in anyway..... anti squat is the whole reason for good damping. Unlike axle wrap, anti squat has small enough magnitude that it can be controlled by good shocks. This is why the trend is toward Baja style extravagent shocks that will eat up anti squat, but because of the basic facts of life of a shock (force exerted related to relative velocity of end points for the inginiero's of the group) it does not limit flex in rock crawling situations where speeds are less than 3mph.

Not claiming to be a God here, but I have the degree, (ME, FIT 2000) and as much practical experience as I can cram into life, and people have been down these roads before, watch and learn what is done to deal with these problems that we all have, and you will get the perfect suspension one day.

BTW, for those of you talking about having a good handling rig on the street, the key to good handling is increasing damping, and decreasing wheel travel. Life of a rig is a compromise, unless you make the trailer it sits on ride real nice <IMG SRC="smilies/smile.gif" border="0">

Originally posted by Donovan:
<STRONG>With a leaf spring your instant center is way back compared to a link type setup. So your rear should lift really hard under accelertion, shouldn't it in theroy. But they didn't lift that hard.</STRONG>

From a straight geometrical sense you are correct. But since the leaf's don't tend to droop as easy or as much as a linktype setup, in the real world it doesn't work that way.

A good example of this is a droparm equipped regular leaf setup. I had a Willy's in my shop for a cage. It had a simple springover with CJ rear springs. When you loaded up the suspension (brakestand, trannystall) it would lift the rearend about 16" (long droparms), it would actualy bind the rear CV. We had a good laugh about this and tried to convince the owner, but to no avail. His suspension isn't any different geometrically than a non droparm springover, but effectivley the amount of jacking is very limited by the limited droop of the leafs, and in his case, the drooparms remove this limiter.

The problem with a very rear biased IC (hi antisquat) set up, is very apparent on a steep climb, when the rear susp. jacks and takes the effective CG and moves it close to, or past the rear axle centerline. For those of you out there with video collections, check out Sam Patton in one of the first Mr.Ed's RCC videos for a visual example of his CJ humping a ledge and not going anywhere, besides almost going over backwards! Another good example (and in NO WAY a rip on G.) is Grady's failed attemp a the TankTrap at TTC a couple of years back. Wheelie's while climbing are bad...MMMMMMMKKAY?!

Sorry for rambling <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by foley:
[QB]Unlike axle wrap, anti squat has small enough magnitude that it can be controlled by good shocks. QB]

you have a good point but i have to disagree, shock force depends on velocity, anti-squat during dragracing is fast and shocks can make a significant difference, however anti-squat during rockcrawling is usually very slow and the lowspeed valving required to do this will make the vehicle ride terribly because the wheels will not be able to fall into holes. if you can design good geometry in the beginning you will not have to fix it later with shocks and sway-bars.

Patman is right, and leaf springs are very different than a link type set-up, the IC is not at the front eye bushing, the rear half of the spring F's up everything so its not easy to fugure out, the arc of the spring, spring-over or spring under, the ratio of the front and rear stiffness all affect the IC, thats why the buggy leaf setups work different, it throws the leaf's rear stiffness out whack. but non buggy leaf spring setup can work well.

Ok, been reading this for 2 days and can't resist joining in.

On engineers. they are supposed to be the ones that apply scientific knowledge to the real world, everybody here that has built a suspension, tested it, found something wrong, and rebuilt it is using engineering fundamentals. The real trick is trying to stay ahead of the guess and check curve by applying some suspension theory and math/geometry basics to the real world to minimize the number of iterations necessary to make suspension work.
Bottom line, if you think first, you'll build and tear up less. The thinking part involves learning some theory which is where the books come in, and also looking at different applications (desert, drag, circle track, etc) to apply their theories in ways that will benifit us. SO QUIT BASHING BOOK KNOWLEDGE AND ENGINEERS! As long as there's some attempt to apply it to the real world (dirt and rocks) a little book learning and some theory can't hurt you. A lot of theory starts out as "what we really want is for these links to be like this," and ends up as: "but they'll only fit the frame if we mount them like so, but what will that do in the real world and will I like it."

OK, moving on. A kicker shock can work to limit axle wrap, but only in a transient condition. Eventually a shock will move and the pinion will come up and possibly bind and break the joint. If you're up the rock by then, great, if not you're hosed. That's why a solid bar is probably better, or at least a limit strap on the shock to keep it from going too far. With a limit strap, you don't limit the suspension travel and articulation, you don't have to worry about the axle snapping back from a wrapped position and hopping,and it keeps the pinion from binding.

One factor in a leaf suspension compared to a link suspension is that a leaf will wrap and store some of your rotational energy when you stand on the gas. This cushions the contact patch of the tire from a shock load and can help get you started without breaking loose. Circle track racers have some really cool suspension designs to make the absolute most of limited traction, and one of them is a 5th coil over. Basically it's a traction bar (ladder bar) with a spring and shock on the frame end where we would normally mount a shackle that can be tuned to allow the suspension to wrap up in a controlled fashion. Since we're almost always traction limited on the rocks, how about incorporating some of this ideal into a rock crawling suspension?
Well, that's just what a leaf does, it absorbs some torque and releases it later.
So how about this? We let the axle wrap up some, but keep it limited enough to avoid spring and driveshaft damage, and use a kicker shock to keep it from snapping back down and hopping.

On solid bars for a conventional rear leafspring setup to prevent axlewrap:
I've found there is a nice "sweet spot" in a leaf spring suspension that will allow you to mount a solid traction bar, either at the pumpkin or one bar above each spring and not bind up. It's typically above the front spring eye and a little behind it, if the bar is mounted 6" or so above axle centerline. Couple of things to help support this:
Check out the front of a solid axle GM truck with the factory suspension. Notice where the swaybar and draglink ends are located? These trucks don't have any bumpsteer in factory trim (at least not much) so the spring and links must work together pretty well.
So, I dug up a spring design manual, laid out the geometry on some wrangler springs and a buddy built a set of bars to the paper drawings. Turns out it works with very similar geometry to the factory GM front. No wrap since there is a bar mounted above each leaf spring making the equivalent of a 4 link, and it still articulates like crazy. The thing to keep in mind is that the leaf is acting like a link in this case. Kind of a flexible one, but it's a link. Same effect can happen with a bar below the leaf, but we generally don't like that since they can drag on the trail. Mounting the "traction bars" this way (above each spring) can give you better anti-squat characteristics than a ladder type bar with a shackle on the end. The ladder bar is nice for really planting the tires on more level stuff, but I wouldn't want it in Moab. When you stand on it in a rig with this type suspension or traction bar the vehicle really comes up. Check out the yellow willy's in TTC 2000 in the drag race. I bet it raised up 8" when he took off due to this effect.
The length of the bar can be varied to change where on the vehicle the force acts, but once again the real world steps in a whacks the ideal bar with rock so we're left with stuff that's mostly funtional but not perfect.

Some thoughts on coils vs leafs with links. Coils are a lot more "tidy", especially when wrapped around a shock, but leaves package flat, which leaves a lot more bed space if that's priority.

enough rambling for me, keep the ideas flowing, learning stuff is why most of us come here.

[ 07-20-2001: Message edited by: Stephen ]

Originally posted by foley:
<STRONG>I haven't read all this, but I am gonna pipe in anyway..... anti squat is the whole reason for good damping. Unlike axle wrap, anti squat has small enough magnitude that it can be controlled by good shocks. This is why the trend is toward Baja style extravagent shocks that will eat up anti squat, but because of the basic facts of life of a shock (force exerted related to relative velocity of end points for the inginiero's of the group) it does not limit flex in rock crawling situations where speeds are less than 3mph.

Not claiming to be a God here, but I have the degree, (ME, FIT 2000) and as much practical experience as I can cram into life, and people have been down these roads before, watch and learn what is done to deal with these problems that we all have, and you will get the perfect suspension one day.

BTW, for those of you talking about having a good handling rig on the street, the key to good handling is increasing damping, and decreasing wheel travel. Life of a rig is a compromise, unless you make the trailer it sits on ride real nice <IMG SRC="smilies/smile.gif" border="0"></STRONG>
Dont think you can control anti-squat with damping,not in rock crawling anyway.

wait... u mean rear steer is when I accelerate and decelerate in my jeep TJ it wants to wiggle its ass... God I hate that.. Esp. during breaking... and esp. on ice.. cause it spun me off a mountain once allready

How do I fix it besides getting rear leaf springs.

Coachgeo3,
Read replies to your original post, I left one there for you! I hope were not done with this topic I loved all the excitement it sturred up!

Here is another bit of information I learned the other day. If you are running a four link with two of the links triangulated and two of the links parallel the roll axis begins at the point were the triangulated links meet and extends at the angle that the parallel links run.

In my opinion axle wrap=BAD!

Stephen,
Glad to see another thinker is aboard! My kickers never bind! Using an automatic or lower gears also helps you start slowly without the loss of traction(contact patch will not experience as great of a shock). Thanks for supporting the Engineering Community! Keep educated talk flowing.

By the way I'm Back everybody, Got to experience LAPD twice in one day. Once I got pulled over (blocking an intersection during rush hour traffic that I had no control over), and the next time I got to watch a High speed pursuit down Wilshire Blvd. Kind of exciting watching a high speed pursuit five feet from you.

Anyone ever go urban wheeling? Truckloading ramps and large steps?

Did anyone see Pig Pen Roll on the 'con this weekend?

you have a good point but i have to disagree, shock force depends on velocity, anti-squat during dragracing is fast and shocks can make a significant difference, however anti-squat during rockcrawling is usually very slow and the lowspeed valving required to do this will make the vehicle ride terribly because the wheels will not be able to fall into holes.
Exactly right... that's why kicker shocks work well against wheelhop but don't work well in super-slow crawling. That's why dialing up the RS9000's for fast transient corners (like mountain roads) can hide the need for swaybars, but on the trail, the shocks won't hold against a steep sidehill.

if you can design good geometry in the beginning you will not have to fix it later with shocks and sway-bars.
Shocks certainly ARE part of the equation, but they are similar to steering dampeners, in that a good steering system needs very littly dampening, but poorly-designed steering systems have to use LOTS of dampening (multiple steering stabilizers) to mask bigger problems. IOW, you can strap four steering stabilizers on and damp out 'Death Wobble' symptoms -- or you can fix the geometry and remove the cause of those symptoms.

Randii

..BUT!!..If we point our phasers at the ditherium crystals and fire up the flux capacitor...Can we still get out on impulse power???...That is the question!!!! <IMG SRC="smilies/puke.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">