Welcome to the next installment of the

Topic of the Week

The subject for the week is custom suspension work.

I'd like to keep this a bit more involved than just building your own spring packs my mixing and matching to build new leaf springs.

Some suggested points of discussion:
- Non Jeep components (using minivan coils on your custom 4 link)
- Four links
- Three links
- Triangulated links
- Semi-eliptical
- Forced articulation
- Squat vs Anti-Squat

Let's get twisted with this one.

Ok, well, I'll start out with a question.....

If built right, can a 1/4 eliptical system be used on a daily driver?
Just curious.. Ive seen how well the 1/4 eliptical systems work, but I know that most people don't suggest them for daily driving..
Scott

i have a question as well....

i seen on some website where they used a single spring pack for the suspension. it was on a yellow jeep. my idea is to do somthing simular as they did. i want to build a cross member that is slightly lower then the frame so that the axle will not come into contact with it. i would then mount some sort swivle to the spring and the frame. the only thing the spring would do is provide a path for articulation and heigth. i would have to use a four link or three link to keep the axle posistioned front to rear. the axle would have up travle until the spring lay flat agienst the cross member and the other side would droop as the same amount. in this setup, would you have to use shacke mounts on the axle or a solid mount? also, if you use a shacke mount on the axle, what would stop the axle from shifting from one side to the other (basically like one side would return to center the shackle facing the wrong way)?

does anyone have the link handy for the jeep that i am talking about? i am sure someone on this board has seen it or knows what i am talking baout because i orignally got the link from this board.

any other input??????????????

Originally posted by 1badjeep
Ok, well, I'll start out with a question.....

If built right, can a 1/4 eliptical system be used on a daily driver?
Just curious.. Ive seen how well the 1/4 eliptical systems work, but I know that most people don't suggest them for daily driving..
Scott

YES. The problem with most 1/4 elip packs it that they only provide spring action during uptravel and not much, if any, down. This can be solved by adding small leafs to the bottom of the pack, assuming the pack is stationary. 1/4 elip was first seen on horse-drawn carriages. Its first automotive application was on race cars though. If it can make a race car handle accurately enough on a track, I imagine it you could get it to work as a daily driver. How easy it would be, I don't know though.

J. J.

Originally posted by AGGIECJ-7
i have a question as well....

i seen on some website where they used a single spring pack for the suspension. it was on a yellow jeep. my idea is to do somthing simular as they did. i want to build a cross member that is slightly lower then the frame so that the axle will not come into contact with it. i would then mount some sort swivle to the spring and the frame. the only thing the spring would do is provide a path for articulation and heigth. i would have to use a four link or three link to keep the axle posistioned front to rear. the axle would have up travle until the spring lay flat agienst the cross member and the other side would droop as the same amount. in this setup, would you have to use shacke mounts on the axle or a solid mount? also, if you use a shacke mount on the axle, what would stop the axle from shifting from one side to the other (basically like one side would return to center the shackle facing the wrong way)?

does anyone have the link handy for the jeep that i am talking about? i am sure someone on this board has seen it or knows what i am talking baout because i orignally got the link from this board.

any other input??????????????

You would have to use shackle mounts unless you wanted it to ride like a rock. A leaf pack's ability to dampen bumps is based on the freedom that it has to deform. This deformation/movement occurs at the shackle. Without the shackle, the leaf spring would just act like a metal bar attached to your axle. So you need shackles.
The Jeep that you are talking about, which really isn't a Jeep but a custom tube-buggy, was called Twister. I haven't heard much about it recently or seen it in a magazine recently. I wonder if the owner sold it or something. But, since you'd need shackles, it would be the 4-link / 3-link setup that would keep your axle from inverting its shackles. I should also note that, after doing this same setup in his front end, he changed it over to a coil setup for some reason which I do not know.

Oh, I just remembered. Another Jeep that has the setup that i think you are talking about is here: http://www.sierrarockcrawlers.com/tech/projects/wackywillys/projectwackywillys.html

J. J.

Originally posted by AGGIECJ-7
i have a question as well....

i seen on some website where they used a single spring pack for the suspension. it was on a yellow jeep. my idea is to do somthing simular as they did. i want to build a cross member that is slightly lower then the frame so that the axle will not come into contact with it. i would then mount some sort swivle to the spring and the frame. the only thing the spring would do is provide a path for articulation and heigth. i would have to use a four link or three link to keep the axle posistioned front to rear. the axle would have up travle until the spring lay flat agienst the cross member and the other side would droop as the same amount. in this setup, would you have to use shacke mounts on the axle or a solid mount? also, if you use a shacke mount on the axle, what would stop the axle from shifting from one side to the other (basically like one side would return to center the shackle facing the wrong way)?

does anyone have the link handy for the jeep that i am talking about? i am sure someone on this board has seen it or knows what i am talking baout because i orignally got the link from this board.

any other input??????????????

No links but take a look at older corvettes and jaguars. Tranverse leaf set ups like that are still in use. You'd have to use a sliding shackle set up to allow the spring to flex

Ok..what's rear steer? Heard it mentioned but not quite sure what it is. 1/4 elleptics are suppost to have this.

Squat is where the axle rotates foward under power. The vehicle doesn't move though, right.

Originally posted by Weasel
Ok..what's rear steer? Heard it mentioned but not quite sure what it is. 1/4 elleptics are suppost to have this.

Squat is where the axle rotates foward under power. The vehicle doesn't move though, right.

The nature of a link-type suspension is that, as the axle droops, it moves toward the front of the vehicle on an arc that matches the length of the links. It goes back as it goes back up. Thus, when one side of the axle is down and the other is at full stuff, the one that is dropping is going to actually be further toward the front of the vehicle than the side that is up. Thus, your tires are actually pointing in a direction other than straight thereby steering your rig from the rear. There are ways to compensate and minimize rear steer on a typical, straight forward link setup, but you can never COMPLETELY eliminate unless you are doing some funky setup that I don't know about. (Which probably exists, I'm sure.)

With squat, the vehicle is most likely moving but only as a result of the axle's torsional forces. Suffice it to say right now that it is when the rear of your vehicle goes down under heavy accelleration. Anti-squat is where the rear of the vehicle actually goes up under heavy acceleration. (As is the case of most dragsters that you see on TV.) Whether the rear goes up or down depends on the placement of your links. The torsional force at your pinion is what makes it squat. I know how to design a suspension that has either or how to design one that minimizes one or the other but not really how to explain ti that great. Most 4x4 suspensions can only dream of having anti-squat as designing links to work for anti-squat is next to impossible with a truck as high as we build ours. It really isn't even that useful in the 4x4 application anyway. Too much squat is a problem in the 4x4 world though. A few years ago there was a big yellow Land Cruiser in TTC that had TONS of squat. Almost so much that, when he took off, his front end would pop a wheelie. That was way too much squat, but being that he had to re-designed his supension 4 days before the comp, I suspect that squat wasn't a big concern for him. :)

J. J.

Originally posted by Weasel
Ok..what's rear steer? Heard it mentioned but not quite sure what it is. 1/4 elleptics are suppost to have this.



Rear steer is exactly what is sounds like...steering in the rear...no 1/4 elep. do not have to have this...the rear steer is setup basically(for the begginer sake) by putting a front axle in the rear and using hydraulic steering to use it...1/4 elep is just using a 1/4 of a spring pack as your spring but you must use either a three or 4 link setup with 1/4 elep...hope this clears this up a little

Originally posted by Supergper


Rear steer is exactly what is sounds like...steering in the rear...no 1/4 elep. do not have to have this...the rear steer is setup basically(for the begginer sake) by putting a front axle in the rear and using hydraulic steering to use it...1/4 elep is just using a 1/4 of a spring pack as your spring but you must use either a three or 4 link setup with 1/4 elep...hope this clears this up a little

I think he was refering to the steering affect that you get with a link-type setup, not steering in the rear. :) Also, 1/4 elip is HALF a normal spring pack. The name "1/4 eliptical" comes from the spring pack being one quarter (90*) of a full cricle (360*). Traditional springs are, technically, 1/2 eliptical leaves. Horse-drawn buggies back in the day also used FULL eliptical suspensions. I bet they flexed like crazy! :)

J. J.

Great TOTW!

This is what I'm currently working on, would someone out there be able to explain how to properly design a rear 'link' type suspension? My truck came with just leafs and in the front its got a panhard bar, so I'm starting from scratch...

I'm also interested in how to choose coil springs? I've got a set of front TJ coils, but I'm not sure how well they'd survive in the back of a fullsize...

Andy

Originally posted by patooyee


I think he was refering to the steering affect that you get with a link-type setup, not steering in the rear. :) Also, 1/4 elip is HALF a normal spring pack. The name "1/4 eliptical" comes from the spring pack being one quarter (90*) of a full cricle (360*). Traditional springs are, technically, 1/2 eliptical leaves. Horse-drawn buggies back in the day also used FULL eliptical suspensions. I bet they flexed like crazy! :)

J. J.

You got me on that...I meant the 1/4 elip is 1/2 a spring pack or 1/4 of a full 360*...If he was refering to the steering effect...well you shouldn't get any steering effect *IF* your links are setup properly

I am not 100% sure but I am very certain that, if using the conventional link-type system that people are using on 4x4's these days, there is NO way to ever get rid of ALL rear steer effect. I say this because, if one side is at full droop and the other is at full stuff, one side will always be a different distance from the same respective point on it's respective frame rail in relation to the other side. The longer you make the links and the better placement that you have lessens the rear-steer affect, but you can never completely be ridden of it, even if you don't feel it happening. I think that, technically, it impossible to get rid of 100% of the rear-steer affect.

Now if you're talking about on-road, relatively always level surfaces, you will have no rear steer since both sides of the axle will be at the same respective point in its arc of travel. (Assuming that all your links are symetrical.)

Just think about it a little. It's all about geometry.

BTW, how come I am the only one spouting my limited knowledge of link-design on this thread so far? I know there are some big-dogs out there that know more than I do! Come awn!

J. J.

There are ways to compensate and minimize rear steer on a typical, straight forward link setup, but you can never COMPLETELY eliminate unless you are doing some funky setup that I don't know about. (Which probably exists, I'm sure.)


sure is, I'm building a triangulated single arm link on the rear of my xj, there will be NO rear steer when fully flexed out. I will post pics as the build up continues. the secret is, there will only be one mount conecting the entire rear axle to the frame in the centre, just before the mount will be a wheel bearing off a front wheel drive car sandwiched between the arm and the mount,

when a 4 link flexes the axle side that drops down gets pulled toward the front of the truck because the link folows it's axis from where it is located at the frame, so it does not travell truely down but on an arc of 360 degrees.

my system will only pull the entire axle forward only and not one side only if both wheels come off the ground, when one side drops the bearing will spin and the axle could essentially turn upside down with out steering toward the front of the truck.
o.k so it's not "my system" I found it in J.P. mag a few months back, and let me tell ya it works sweet.

Dessert toy has a setup that keeps the rear steer almost to zero.

He posted this pic awhile ago, and we all thank him for it.

Originally posted by cherokee pete



sure is, I'm building a triangulated single arm link on the rear of my xj, there will be NO rear steer when fully flexed out. I will post pics as the build up continues. the secret is, there will only be one mount conecting the entire rear axle to the frame in the centre, just before the mount will be a wheel bearing off a front wheel drive car sandwiched between the arm and the mount,



I can't wait to see this. It's not exactly the typical link setup that everyone else uses, which is why I guess you can say that you aren't going to have any rear steer. What springs are you planning on using? How are you going to keep the axle from moving side to side?

J. J.

Originally posted by emsoffroad
Dessert toy has a setup that keeps the rear steer almost to zero.

He posted this pic awhile ago, and we all thank him for it.

I've thoght about this type of setup for a long time but didn't know anybody in the 4x4 world had done it yet. I still don't see how it has no rear steer, though. Those links still travel on an arc, no matter where they're located. I realize that you said, "almost" zero, so I guess that answers my question. :) With a setup like that it is impossible to get rid of ALL rear steer.

J. J.

I can't wait to see this. It's not exactly the typical link setup that everyone else uses, which is why I guess you can say that you aren't going to have any rear steer. What springs are you planning on using? How are you going to keep the axle from moving side to side?

I'm using the old coil springs that were in the front (warn black diamond 4 1/2) the spring rate may be a bit much for the rear, but the coils are 5 years old and the rate they were when they were new may have changed a bit, I will be adding some more weight to the rear (tool box and 35 bogger spare) if it dont work I may bite the bullet and get coil overs,

To support it lateraly I will make a track bar with rod ends and try to keep it parallel to the axle.

Originally posted by cherokee pete


I'm using the old coil springs that were in the front (warn black diamond 4 1/2) the spring rate may be a bit much for the rear, but the coils are 5 years old and the rate they were when they were new may have changed a bit, I will be adding some more weight to the rear (tool box and 35 bogger spare) if it dont work I may bite the bullet and get coil overs,

To support it lateraly I will make a track bar with rod ends and try to keep it parallel to the axle.

What you're doing sounds remotely similar to the rears in the Scorpions. I see how you're keeping axle wrap from occuring and I see how you're getting the axle to follow a certain path from side to side with the track bar (also known as a panhard rod), but I still don't see what keeps the axle from cocking from one side to the other randomly. You have a link in the middle that the axle can pivot any direction on and a link to make the side to side movement predictable, but so far nothing I know of that will keep one side of the axle from moving forward and backward. Maybe you could draw and scan a pic or something so I would understand.

J. J.

I also have another question concerning the transversley mounted spring pack. what would stop the jeep from just leaning to one side when it is sitting on level ground. it wouldnt be the use of a track bar, if this was the case then the jeep wouldnt flex at all. as is the case with the 4/3 link setup.

i would think that you would rely on shocks to do all the work of keeping the jeep level and lrsning like the tower in Pizza.


any clues as to how to solve this problem??????????

Originally posted by patooyee


I've thoght about this type of setup for a long time but didn't know anybody in the 4x4 world had done it yet. I still don't see how it has no rear steer, though. Those links still travel on an arc, no matter where they're located. I realize that you said, "almost" zero, so I guess that answers my question. :) With a setup like that it is impossible to get rid of ALL rear steer.

J. J.

here's the triangulated rear suspension that the boys at S&N Fab came up with for my 99 TJ...

The constraints that I gave them was that I wanted to run at least 37s, and that the TJ had to be (appear to be) steet legal as I wanted it to remain my daily driver, which boiled down to the rear fenders and the gas tank had to remain, but I also wanted a trail rig that was as capable as possible

Jason's design goals were
- stay within the TJ's rear suspension area (no extended wb)
- to have a predictable, balanced and stable ride both off road and on
- minimize rear steer
- have the pinion always pointed at the TC yoke

As far as I'm concerened, he nailed it...the off road handling (once we dico'd the front AR) was near perfect, and the on road handling is very nice...I've been driving it to work and back every day for several weeks now, and I love it...

and interestingly, it has ended up with a bit of anti-squat...it's fun to watch people's faces the first time they ride in it, as I hit the gas and the whole rig lifts up a couple of inches :D :D :D

http://www.sn-fab.com/brett/roundy017.JPG

http://www.sn-fab.com/brett/roundy045.JPG

http://www.sn-fab.com/brett/roundy050.JPG

http://www.sn-fab.com/brett/roundy068.JPG

specs and pics (http://www.sn-fab.com/brett/)

Man this is a good topic of the week.. Does anyone have a COMPLETE write up on a 1/4 eliptical setup installed into a jeep?? More than one would help me for comparisons sake!
Thanks,
Scott

664n668, just to get my words right, that is a three link system, right? Because it has three attachment points on the axle? Even though you have 4 attachemnts to the frame? Is there a term for that top link? (Y link or somthing?)

Thanks!

here is one of the best write ups you can find on 1/4 eliptic systems. http://www.jeepaholics.com/tech/quarterellip/ Several of my friends have built their systems off of the info on this page and they work killer. One thing they have found is that they tend to bend springs unless they mount one or twoe helper springs on the bottom of their spring pack under their main leaf. Also limiting straps are a must! I plan on setting up my scrambler like this as soon as i save up enough pennys to buy my 14 bolt rear and 60 front. :beer:

Okay, I'll raise the question for older Jeeps, or any other offset rear-diff rig. How can you do anything more custom than SOA on these rigs that have offset diffs?
I've been trying to figure out a way to convert to coils on my 5, but everytime I put it to paper, the 'arc' of the droop looks like it will tag the drive shaft if the suspension droops too far (3 or 4 link setup). Limiting straps could be used to fix this, but are there any other options? Connecting the triangulated center link (2 points on x-member, one point on axle) could be accomplished by welding a bracket for the single mount point to the axle housing itself (instead of the diff). This point would control axle wrap, but flex steer would still be horrible. I supposed a panhard bar could be used to keep the axle centered (side to side), but that doesn't solve the flex steer issue either. 1/4 elliptical setup has the same issues as the coil spring for offset diffs (to a lesser extent). I'd like to see a real solution, not a "just swap your xfer and rear axle for a centered setup" solution. I couldn't find anything using the search tool. Am I just :rasta: :rasta: here, or am I just missing something in the design of these 3/4 link setups? Thanks, Bret

Probably the best advice to give in regards to suspension design is to pick up Milliken's book, "Race Car Vehicle Dynamics." Either pester your local library to pull it in for you or plan on shelling out about $85 for your own copy.

It will answer most any question such as, "what is rear steer" and "how do I design it out."

cmk

Originally posted by Archie_G
664n668, just to get my words right, that is a three link system, right? Because it has three attachment points on the axle? Even though you have 4 attachemnts to the frame? Is there a term for that top link? (Y link or somthing?)

Thanks!

well...I guess if you had to name it, it would be a 3-link with upper wishbone and triangulated lowers :D

It is possible to design a suspension that has zero "rear steer." It just isn't very feasable.

Imagine if you will, a rear diff centered under a vehicle. Imagine that the center of rotation (articulation) is the center of the diff. Now imagine 2 completely horizontal and parrallel "control arms" running from the frame to the diff. Now since the center of rotation is the diff, then the high side is going to travel the same distance as the down side.
http://www.AzChatfield.net/Perfect.jpg

Obviously this can't possibly work in our application. Our diff is certainly not the center of rotation. Ifwe use a 4 link setup, the diff pivots under an imaginary point, if we use a 3 link, then it pivots under the top link. And we will get much more down travel than up travel. To counteract some of the rear steer, we can use "triangulated" lower arms (wider on the axle than mounted on the frame). This will help some.
http://www.AzChatfield.net/Angled.jpg

Obviously, these pictures are not to scale and are not perfect, just meant to give an approximation.

____________________
- Mike
"Why do I have to learn this? Who uses geometry in the real world?"

Or ditch all that linkbar stuff and just wheel. For those who don't give a rip about bilding the ultmate wheeler just go with a nice long spring with an offset and if you want more drop then try a 3/4 eliptic setup. With all the $$$ you saved in hiem joints and link bar matieral you can buy a lot of :beer:

http://www.respite.org/images/cj66dean/soupcan2.jpg

got a good one.... first off, i will be changing everything next year but for now i got to deal with a few little issues.......... my upper rear control arms on my tj ........ the damned 7/16 bolts are breaking.... i believe just too much weight from axles and tires.... sooo,,,,,,,,, 1, could i just triangulate my top links goin to heims, loose the trac bar and leave the tera lowers.... im not lookin for more flex as of yet, just bigger stronger links to avoid the bolt breakage issue for now... 2 fawk all that shit (since ill be changing) and just loose the sleeve inside the bushing and run a bolt with the correct shoulder to fill the void where the sleeve was and walla i have a stronger/ bigger bolt..... either way will be a one year maximum temporary fix....



oh and if i triangulate my uppers, leaving the lowers alone..... can i loose the trac bar....


i know i know the geometry wont be perfect.... just want similar results i got now without the breakage

Originally posted by 66CJdean
Or ditch all that linkbar stuff and just wheel. For those who don't give a rip about bilding the ultmate wheeler just go with a nice long spring with an offset and if you want more drop then try a 3/4 eliptic setup. With all the $$$ you saved in hiem joints and link bar matieral you can buy a lot of :beer:

http://www.respite.org/images/cj66dean/soupcan2.jpg

Are you still running the offset rear diff on your 5? You say you're running offset springs, would these be the front spring packs from a Waggie? If so, the 5 or 7 spring packs? Or did you just start with Waggies and build custom packs with various springs? BTW, that's a sweet 5! :D :D Thanks, Bret

For fabricating suspension links with adjustable rod ends, what is a good source of rod ends, threaded inserts, mild steel tubing. what about poly bushed rod ends? Are these up to snuff for off roading?

[QUOTE]Originally posted by 664n668
[B]

here's the triangulated rear suspension that the boys at S&N Fab came up with for my 99 TJ...

The constraints that I gave them was that I wanted to run at least 37s, and that the TJ had to be (appear to be) steet legal as I wanted it to remain my daily driver, which boiled down to the rear fenders and the gas tank had to remain, but I also wanted a trail rig that was as capable as possible

Jason's design goals were
- stay within the TJ's rear suspension area (no extended wb)
- to have a predictable, balanced and stable ride both off road and on
- minimize rear steer
- have the pinion always pointed at the TC yoke

As far as I'm concerened, he nailed it...the off road handling (once we dico'd the front AR) was near perfect, and the on road handling is very nice...I've been driving it to work and back every day for several weeks now, and I love it...

and interestingly, it has ended up with a bit of anti-squat...it's fun to watch people's faces the first time they ride in it, as I hit the gas and the whole rig lifts up a couple of inches :D :D :D

My question:

How much loss of stability would I suffer by mounting my coil overs perpandicular to the rear axle and implamenting a "track bar" VS mounting the coil overs in the triangular geometry.
The triangular geometry will eliminate the track bar "good for flex" but most of my storage space for tools and needed equipment will be gone.

My design requirements:
1. 7-8in of total lift, with 35-38in tires Keeping it small, what light tires but with some meat.
2. Good flex, 17in
3. Good Higher speed off road performance for small jumping like 2-3ft of air
4. Would be safe at highway speeds,
5. Relocate the gas tank
6. Do not want to convert to a dry sump system
7. would like as much cargo space as possable.
8. long arms with spherical greasable bearings at frame and rubber at axle mounts.
9. will be running 1TON axles front and rear, not sure how the coil overs will perform with these heavy axles.
10. I like a soft ride, so I plan to using airbags at my bumpstops and removable rubber limiting straps.
11. Frame and what not will all be reienforced but kept as light as possable.
12. Why bolt it IF I can weld it.

Give me some ideas!!:barf:

Originally posted by ashmanjeepXJ
Give me some ideas!![/B]

Take a good look at Campbell Ent.'s Rock Buggies:
http://www.campbellent.com/full%20size/oct13$04.jpg (http://www.campbellent.com)

They're using a Coil Over front (14" travel) 1/4 Ellip rear (17" travel) which seems to stand up pretty good to the abuse dished out. I believe Shannon is running F&R Terra 60's with limiting straps at the center of the diff only.

_________________
- Mike

i want to hear more about the anti squat susp. all the fixed link setups i see squat under accel. So how do you make one "Jack up". i see this being good for a couple of offroad situations, but it probably has 20 side effects that are bad. Say you were getting high centered in a spot if your suspension raises the chasis up , you are home free. But you would need to limit it so that it can only drop under extreme twisting forces. So that when you head down hill you are not going to tumble because of some free flowing susp.

Originally posted by TINY
i want to hear more about the anti squat susp. all the fixed link setups i see squat under accel. So how do you make one "Jack up". i see this being good for a couple of offroad situations, but it probably has 20 side effects that are bad. Say you were getting high centered in a spot if your suspension raises the chasis up , you are home free. But you would need to limit it so that it can only drop under extreme twisting forces. So that when you head down hill you are not going to tumble because of some free flowing susp.

The only way I know of to make anti-squat is to make it so that your upper links are actually below their mounts on the axle. This would be next to impossible for a 4x4.

J. J.

Originally posted by patooyee


The only way I know of to make anti-squat is to make it so that your upper links are actually below their mounts on the axle. This would be next to impossible for a 4x4.

J. J.

hmmmm...I'll go out to the parking lot and tell my rig that it's doing the impossible...I'll let you know if it starts behaving :D :D :D

AGGIECJ-7,

Is this the single leaf spring you were refering to?
http://www.extreme4wheelin.com/images/poker_01_19_02/p1190736_med.jpg

Single leaf susp. (http://www.extreme4wheelin.com/images/poker_01_19_02/p1190736_med.jpg)

I can't see if there is a pivot point in the center at the frame, but from some of the flex in other pics I can't imagine it not have a pivot point.

Also, I don't see any shackle at the axle, it just looks like a solid mount.

Anti-Squat is achieved by having equal length converging control arms. What happens is as torque is applied to the tires, the axle tries to "wrap" in the opposite direction. In order for the axle to wrap, the suspension must go down (driving the tires into the ground and lifting the rear). On Dragsters, this is good. Off-road this is debateable. On steep climbs, what can happen is the momentum of the body going up can actually pull rear wheels off the ground, causing wheel hop. Some argue, however that the best setup is just a little anti-wrap.

With no anti-squat, the links are equal length and parallel. In this instance, the axle simply isn't allowed to wrap. As a result, the shifting weight causes the rear to squat. Some feel that this is more desireable off-road than anit-squat.

I think the best option is to have a shorter upper arm. At first, it allows the axle to wrap, raising the back and increasing traction as it does. To a point, then it doesn't allow the axle to wrap anymore, as it approaches this point the amount of anti-wrap gradually decreases.

Here is a pic that shows some examples, the pic is not to scale and is exagerated slightly.
http://www.AzChatfield.net/Squat.jpg

_________________
- Mike

Originally posted by hubeid


Are you still running the offset rear diff on your 5? You say you're running offset springs, would these be the front spring packs from a Waggie? If so, the 5 or 7 spring packs? Or did you just start with Waggies and build custom packs with various springs? BTW, that's a sweet 5! :D :D Thanks, Bret

The front and rear springs are Dakota springs and they run a 10" offset. The fronts are stock and the rears are HD replacement from JC Whitney but you can find 3/4 Dakotas out there that have good springs for the rear. The rear is a 90 RC60 with 14bolt ends.
http://www.respite.org/images/cj66dean/myjeeprear4.jpg

Originally posted by Ketchup Dog
Man this is a good topic of the week.. Does anyone have a COMPLETE write up on a 1/4 eliptical setup installed into a jeep?? More than one would help me for comparisons sake!
Thanks,
Scott

Check out Knorr's web site http://www.bc4x4.com/thbsjeep/ not saying he is an expert, but his junk works decent.

Originally posted by 66CJdean


The front and rear springs are Dakota springs and they run a 10" offset. The fronts are stock and the rears are HD replacement from JC Whitney but you can find 3/4 Dakotas out there that have good springs for the rear. The rear is a 90 RC60 with 14bolt ends.
http://www.respite.org/images/cj66dean/myjeeprear4.jpg

:eek: :eek: Nice rear end;) ;):D Dakota spring huh. Hmmm. Did you have to move your rear spring hangers forward? I see you lengthened the front of the frame since you're not running reversed shackles. My 5 already has the front shackles reversed, so I'm curious if you had to move your spring hangers. I might just run Waggy springs up front and Dakota springs in the back... Not sure now. Thanks for the info! Bret

I just started with building a new frame so no need to move hangers:D If you are going to run these you will for sure need to move the hangers or shackles in the front. These springs are 56" long with the weight of the jeep on them with a 23X33 offset.
http://www.respite.org/images/cj66dean/frame1.jpg

AGGIECJ-7,

Is this the single leaf spring you were refering to?
http://www.extreme4wheelin.com/images/poker_01_19_02/p1190736_med.jpg

Single leaf susp. (http://www.extreme4wheelin.com/images/poker_01_19_02/p1190736_med.jpg)

I can't see if there is a pivot point in the center at the frame, but from some of the flex in other pics I can't imagine it not have a pivot point.

Also, I don't see any shackle at the axle, it just looks like a solid mount.

No pivot on the frame but there are small shackles on the ends.

that is exactly what i am talking about. however what i dont understand is why the axle doesnt just fall over to one side or the other. i dont see how a 4/3 link would stop this from happening. or is it the shocks that stop it. i also dont see how the shocks would do this unless they are nitrogen shocks or something like that

if anyone can get me an email address of someone who has done a trans mounted setup then i could ask them directly

Originally posted by AGGIECJ-7
what i dont understand is why the axle doesnt just fall over to one side or the other.

The spring is mounted to the frame in the center. Because the spring will place force on each side, it keeps the axle from flopping around.

Look at it this way, you've seen 1/4 Ellip setups right? If you take the 1/4 ellip springs and mount them over the axle, so that the frame mount ends are pointing to each other, it is essentially the same thing. Just now instead of 1/4 Ellip (or a normal spring cut in half) it is a 1/2 ellip (or normal spring)

_________________
- Mike
"Springs are for holding the vehicle up, Links are for transfering energy..."

How about this setup:

YJ Rear: SOA w/ Wagoneer springs setup 3/4 elliptical and traction bar
YJ Front: Coilovers w/ 4 link

Why? This setup IMO from experience of seeing an SOA 3/4 in action and seeing coilovers in action would flex great. It would give great approach angle getting rid of the springs in front. It would also be easy. Doing coil overs in rear would be difficult and much more time consuming.

Any bad things about this setup? Would a 4 link up front be ideal for coilovers?

DAMN. This thing has been up here for awhile and I never even saw it.

Originally posted by AzXTV


The spring is mounted to the frame in the center. Because the spring will place force on each side, it keeps the axle from flopping around.

Look at it this way, you've seen 1/4 Ellip setups right? If you take the 1/4 ellip springs and mount them over the axle, so that the frame mount ends are pointing to each other, it is essentially the same thing. Just now instead of 1/4 Ellip (or a normal spring cut in half) it is a 1/2 ellip (or normal spring)



i actually ment why doesnt the body just lay over one one side or the other. if it is mounted to the frame via a piviot point(ie kind of like one end of a shackle) then the jeep is free to teater from one side to the other. this is what gives it the amount of flex that it has

Rear...why cant you take a standard triangulated 4-link and mount the coilovers on the lower link in front of the axle ?

when the axle wraps the lower links are moving upwards hence moving the rear end up (anti Squat) ???

That transverse spring buggy: I would say it's NOT mounted to the frame via a pivot point. The centre bolt goes right thru the spring pack and the frame. To lean, it must flex the spring. If it had a pivot in the center, all roll control would go to the front axle.

Originally posted by AGGIECJ-7
i actually ment why doesnt the body just lay over one one side or the other. if it is mounted to the frame via a piviot point(ie kind of like one end of a shackle) then the jeep is free to teater from one side to the other. this is what gives it the amount of flex that it has

It appears that the spring pack is bolted to the frame through the centering pin holes. This will hold the center part of the spring against the frame -- not really a pivot point:
http://www.AzChatfield.net/miscpics/CloseUp.jpg

So what I'm thinking (not having seen this in person) is that spring is forced flat against that rear section of the frame:
http://www.AzChatfield.net/miscpics/Transverse.jpg

_________________
- Mike

What is Goat Boy Doing on this thread

Originally posted by calpolystud
What is Goat Boy Doing on this thread

WTF go crawl back into the hole you have been hiding in.:flipoff2:

Anti-squat is exactly what the name says it is Anti squat. That means the rear end will raise up under acceleration. This happens when the sum of the moments around the cg are not equal to zero. Basically link angle (referred from the ground)plays the biggest role in determinig squat characteristics. This is my understanding! If you want to tell me I'm wrong go ahead! But it all boils down to Physics. F=MA. People with link suspensions front and rear may experience more anti-squat than other because the rear usually has anti-squat while the front has squat. This makes it seem as though the back is lifting higher when really the front is getting lower.

In theory it is possible to have zero rear steer if you can achieve a zero degree roll axis. Even if your links are not parallel with the ground it is still possible.

I saw that bolt, but I can' t imagine the spring and axle are held to the frame by one bolt.

It looks as if there is one bolt holding it together and the pack looked against the frame, but I didn't think it would hold, especially with all the weight of the axle and tires. Maybe it does, but wouldn't the leaf crack from having so much stress such a small concentrated area?Wouldn't the bolt bust?

Top

"Running trans mounted leafsprings to a central pivoting control arm suspension, the twist on this rig is unbelieveable."

that is a direct quote from the SRC website. i want to do a setup more like the wacky willys because of the amount of flex it has. This setup DOES NOT have the spring bolted directly to the frame like the one on that green rock buggy. here is the website for the wacky willys if you want to look at it again: http://www.sierrarockcrawlers.com/tech/projects/wackywillys/projectwackywillys.html

if anyone has the email address for the guy that is building this jeep, please post it here or PM it to me. i want to ask him a few questions about it

Great TOTW with very useful info.

Ok suspension guru's, how about this? Running trans mounted leafsprings to a central pivoting mount and air bags tied together with a preset presure. When the axle articulates, one bag is compressed forcing its air into the other bag and it expands. When level, the presure would be equal thus keep it from flopping from side to side. Would this work?

Locating the axle (3 link, 4 link, etc) would be personal pref. depending on whether it is front or rear.

Explain again how to figure roll axis and roll center. And what was it with (ahem) "line through the rear of top links, forward to front of bottom links, through a point directly below the imaginary line of the upper arms point of intersection blah blah" and on to the ground. Whatever the hell that is, it hits right at the front tires on mine, good or bad?
Anybody remember what that was, it's from the old God of Suspension thread.

Originally posted by Slagburn
Explain again how to figure roll axis and roll center. And what was it with (ahem) "line through the rear of top links, forward to front of bottom links, through a point directly below the imaginary line of the upper arms point of intersection blah blah" and on to the ground. Whatever the hell that is, it hits right at the front tires on mine, good or bad?
Anybody remember what that was, it's from the old God of Suspension thread.

page seven of the god of suspension thread.
http://www.pirate4x4.com/ubb/uploads/test1.gif

Ok so what would happen if you (in the figure above) dropped the upper arms frame side so that they were in line with the roll axis (so the IC and point A were in the same spot)?

Dean,
what springs are you using for the halves of the upper 3/4 elipitical rear? where did you cut the springs? and where on the frame did you mount them. not too long ago i did a 3/4 install with procomp cj springs and i cut them kinda short. it didnt work too well and the shackles always flipped(didnt seem to hurt anything though). just wondering cuz i was going to dedo my entire suspension soon. just wanted to get some ideas. what traction bar setup do you use if one? do you have a webpage on your jeep by any chance. thnx any help appreciated.

this may have been suggested previously, but wouldn't a panhard rod control any rear steer tendency of a multi-link suspension? I'm just a newb about this stuff, so I could be wrong.

Nope on the panhard bar solution. It's function is to locate the axle laterally. Rear steer results from the axle ends moving fore and aft due to changes in geometry of the links as they move up and down. For example, if hte right rear side of the vehicle compresses and the downward trailing arms move upward, they locate the axle further rearward as they compress upward. If the left side is static or moving downward, the axle turns right and steers the vehicle's end that way.

Originally posted by Tmartin
Nope on the panhard bar solution. It's function is to locate the axle laterally. Rear steer results from the axle ends moving fore and aft due to changes in geometry of the links as they move up and down. For example, if hte right rear side of the vehicle compresses and the downward trailing arms move upward, they locate the axle further rearward as they compress upward. If the left side is static or moving downward, the axle turns right and steers the vehicle's end that way.

yes I know how the rear steer occurs, but if you don't put swiveling joints on the panhard ends, just flat bushing like things (think how shackles mount), it would limit the amount the axle would be able to move fore and aft. might snap your panhard off, but it might work. My other idea is for where you mount the links to the frame, would a sliding plate on a spring attached to that locate the links correctly? So when it gets more horizontal, and thus, longer, it pushes on the spring, moving it back in line with the other link?

http://www.pirate4x4.com/ubb/uploads/test1.gif [/B]

Ok so what would happen if you (in the figure above) dropped the upper arms frame side so that they were in line with the roll axis (so the IC and point A were in the same spot)?

Shuss, the panhard bar runs laterally. It can't function to limit for and aft travel of the axle. Besides that, the links being rigid, you can't limit the natural movemetn of a rigid link with another link without inducing massive bind as one arc fights with another. Imagine a door swinging on it's hinges. It travels thru a natural arc. You can attach something else to the door that will alter that path without bending something. Or do I not understand your suggestion?

Originally posted by AGGIECJ-7
"Running trans mounted leafsprings to a central pivoting control arm suspension, the twist on this rig is unbelieveable."

that is a direct quote from the SRC website. i want to do a setup more like the wacky willys because of the amount of flex it has. This setup DOES NOT have the spring bolted directly to the frame like the one on that green rock buggy. here is the website for the wacky willys if you want to look at it again: http://www.sierrarockcrawlers.com/tech/projects/wackywillys/projectwackywillys.html

if anyone has the email address for the guy that is building this jeep, please post it here or PM it to me. i want to ask him a few questions about it

That thing would be scary to wheel. The way the springs are set up, there is no roll control. I guess it would be pretty cool to have a ramp score of 60 million. :rolleyes:

i guess you are right. i think that i will try a setup like this but it will be solid mounted to the frame.

Originally posted by 664n668
http://www.sn-fab.com/brett/roundy017.JPG

http://www.sn-fab.com/brett/roundy045.JPG

http://www.sn-fab.com/brett/roundy050.JPG

http://www.sn-fab.com/brett/roundy068.JPG

specs and pics (http://www.sn-fab.com/brett/)

This is all I got off your link ...

The page cannot be found
The page you are looking for might have been removed,
had its name changed, or is temporarily unavailable.

--------------------------------------------------------------------------------

Please try the following:

If you typed the page address in the Address bar,
make sure that it is spelled correctly.

Open the www.sn-fab.com home page, and then look for links to the information you want.
Click the Back button to try another link.
Click Search to look for information on the Internet.



HTTP 404 - File not found
Internet Explorer

? ? ? ? ? ? ? ?

? ? ? :confused: ? ? ?

? ? ? ? ? ? ? ?


Waaassuup wit dat ?!?!

Originally posted by tigger4x


This is all I got off your link ...

The page cannot be found
The page you are looking for might have been removed,
had its name changed, or is temporarily unavailable.

--------------------------------------------------------------------------------

Please try the following:

If you typed the page address in the Address bar,
make sure that it is spelled correctly.

Open the www.sn-fab.com home page, and then look for links to the information you want.
Click the Back button to try another link.
Click Search to look for information on the Internet.



HTTP 404 - File not found
Internet Explorer

? ? ? ? ? ? ? ?

? ? ? :confused: ? ? ?

? ? ? ? ? ? ? ?


Waaassuup wit dat ?!?!

sorry man...Neckster just can't seem to leave the damn webpage alone:flipoff2:...he changed things around and broke all the previous pic links

try this:
S&N Fab Coilover TJ link (http://www.sn-fab.com/projects/Brett/index.html)

What about three (BEEF) straight links and a panhard bar??? Simple and to the point

yea, the binding is what I was worried about with the panhard, just was wondering about it as a simple solution. There doesn't seem to be an easy way around rear steer. hmmmm, now if only I was an ME major :D

just read this and thought i would like to ask if anyone out there is running coilovers with mog/portal axles?

I have been looking at portals and it seems that as they raise control arms and shock mounting points so much higher it will limit what you can do with the suspension. Obviously with a portal axle you are not going to be running 6" coils or anything....so isn't that going to limit the amount of travel you can get?

After asking a shop that deals with portals how they are setup usually he mentioned they used stock coils or even just 2" coils and they were talking of fitting 39.5's to a TJ with that setup. So when it flexes down the spring would be falling out very quickly....

Anyways, just wondering how people set up portals as it seems there is more suspension travel by far in a normal axle setup.

aussie custom suspension design, we don't need the stinking leaf attached to the axle. hehe - look closely.

http://www.sv.com.au/jeep/images/TTC2001x/images/9_jpg_jpg.jpg

I have run coils FR/RR on my last rig. I loved the flex but did not like the BOING I bought a new rig that is full leaf sprung and now remember how stable the leafs are, but want to get the FLEX

My question is...
Does the 1/4-ellip setup take the BOING out? I assume so but want confirmation. Also, I have seen a couple different applications:
1)I have seen the leaf pack captured in a clamp which pivots on a spring hanger from the frame. This appears that I would give the "flopping" effect which I disliked about my coils when the suspension was unloaded.
2)The more common I have seen clamps the spring pack rigid to the frame. This makes more sense to me as it would allow the laefs to act in both directions, thus eliminating the "flopping" effect.

Does this make sense? Or am I just rambling? (A.D.D.:D )

Patooyee mentions running small leafs on the bottom. I am having trouble picturing this one. Is he referring to short lefs that would support the main leaf on droop?

I've been thinking ways to run coilovers on rig, but I hav ea car seat in the back that I can't get rid of. I went to the site mentioned I couldn't tell if the coilovers were angled. I understand the concept of the trainglation of the coilovers. Is this my only option to run rear coilovers? Would I be able to put in a wider axle and mount them to the peak of the frame and have the coilovers at a slight angle. Oh by the way flame suit on.

What suspension components from other vehicles could I use to get the equivalant of a 4 inch lift for a 2002 TJ for less than like $400-$600? And what is the best tire to get for off-road, crawling, and everyday road use?