Jason Conover (aka Snortclown) (http://darkwing.uoregon.edu/~jrice/cruiser/FJ45/Suspension/Jason.jpg) came down this past weekend to help install the 1/4 elliptical suspension parts he built for me. Unfortunately, he took a close look at the truggy, shook his head and said: "This ain't going to fit " The doubler puts the NP205 right where the link hanger on the passenger's side needs to go. The only options would be to A) increase the wheelbase by 6" or B) move the hangers back and shorten the control arms by 6". Neither option was acceptable, since there was no way I wanted to end up with a 112" wheelbase and in Jason's experience the shorter links would create unacceptable rear steer. The original design had the link hangers mounted on the inside of the frame, parallel lower links and triangulated upper links. After some measurements and much discussion, we determined that the solution was to switch the design of the 4-link system to one with parallel upper links and triangulated lower links with all hangers mounted to a crossmember beneath the transfer case.

So, with Jason designing parts and both of us building them, we started fabrication of an entirely different 4-link system. After 12 hours on Saturday we had all the parts fabricated. Sunday, we put is all together, with the following results:
http://darkwing.uoregon.edu/~jrice/cruiser/FJ45/Suspension/4Link1.jpg
Here is a view of the link hanger/crossmember:
http://darkwing.uoregon.edu/~jrice/cruiser/FJ45/Suspension/LinkHanger.jpg

The links themselves are 43" in length. The image below shows the movement afforded the rear axle by the links. At this point of axle tilt, the upper and lower arms touch each other. At this maximum amount of articulation, there is only 1/2" of rear steer. A combination of bumpstops and limiting straps will be used to stop the movement before the links collide with each other.
http://darkwing.uoregon.edu/~jrice/cruiser/FJ45/Suspension/4Link2.jpg
We also cut a notch in the frame and reinforced that area for the the springs to be mounted. I will use square u-bolts to attach the springs to the frame.
http://darkwing.uoregon.edu/~jrice/cruiser/FJ45/Suspension/SpringMount.jpg
All in all, a very productive weekend.

very cool

:smokin:

A productive weekend! Holy crap I am lucky to get a new idea started after staring at the problem for a few days, let alone get it done! Way to go, it looks great!

"When I grow up, I want to be like Jack!"

As usual, excellent work, Medusa. So what are you going to be working on next for the Truggy Project? Seems like the drive train and suspension seem to be coming together. Bodywork?

Damn nice work guys!

It looks awesome! Cant wait to see the end result!

-Brett

if i was a 45, i'd definetly want to be adopted by JACK!!!!!!

looks great, can't wait to see the rig when it's done.
what is the ETA you're shooting for?

Totally Awesome Jack...Looks like that rig is going to have some serious articulation...wish I had that on my 40! At least I have the pics now if I want to try it.

NICE!

Thanks for all the kind words, guys. I sure learned a lot working with the SnortClown -- he certainly knows his suspensions and is one fine welder.
So what are you going to be working on next for the Truggy Project?
Brakes, steering and then the bodywork. i hope to finish this winter and have it ready for the rocks next spring.

wowowowow... very nice, clean work!

Speaking of clean..I always wondered what my grime/oil covered 205 is supposed to look like!:D

looks great, out of curiosity though i would like to know:

why didnt you use the lower links to come up to the current height yet just outside the frame and mount them there, clear and no binding

and then just triangulate the upper two link into the current position the lower links go to??

i know nothing of suspension, it just seems easier and would not bind......:confused:

ok...and i think you could mount them to clear your driveshaft, but yeah, then you may have to move your upper link mounts further out on the diff?

is it because the more distance between the outer links would cause more binding than links that are closer together? (inboarding and outboarding style argument?)

or because things outside the frame have a habit of getting hammered by rocks?

or because you had the mounts already welded on the diff and wanted a solution with minimal additional work and time?

I am having a difficult time visualizing just what you are proposing, so my answers might not be fully relevant. First of all, I acknowledge that compared to guys like Snortclown, I am a suspension novice. I do know that there are a handful of 4-link designs that have been proven to work well offroad, and this is one of them.

If you move the front of the lower link outside the frame and then move the upper link "to where the lower links go", you would not have a triangulated system. The upper and lower links would not cross (which they must in a properly designed system). This arrangement, if I am visualizing it correctly, would be just a fancy traction bar. The links have to mount to the axle inboard of the springs. And, No, it didn't end up the way it did because the mounts were already welded on the housing. Jason designed the entire system on paper, we mocked it up before any fabrication was started and all parts were tacked and the suspension cycled several times before final welding.

Finally, I am not sure I want the rear axle to move any more than the suspension currently allows. But IF I did, the way to achieve more movement before binding is to simply build a new pair of upper links with a bend in them above the point where the upper and lower links interfere with each other. IIRC Avalanche uses this suspension design with this trick to achieve more movement.

Gee that sucks, I think you guys need some more practice. When can I drop mine off??

LOOKS KILLER!!!! WOW!!!!!! I am leaning more and more towards the 1/4 setup. So maybe next time a bunch of $$$ falls out of the sky I can set it up. :D

I know very little about this 1/4 eliptical stuff so I've been eager to follow your project. It's really looking good! Absolutely superb craftsmanship !

One question though....it appears as though during articulation the rear dif follows an arc that takes it off center from the center line to the transfer case. If this is true, how much off-center is tolerable? Or is this an illusion from the picture I see ?
Or is there a limitation that comes into play when the springs are attached ?
Or is that what you're after for extreme articulation ?

When this is all done I'd like to do the same to my 40 unless the shorter frame may cause a problem.

The amount of diff arc depends on your link location and how they are designed to move together. The main factor here is rear axle roll axis. The higher this axis is above the rear axle, the more the diff will swing out and to the side as the axle articulates. This can be a good thing to help get the stuffed tire out and away from the inner fenders. If you had your roll axis inline with the pinion, it would not arc as the axle articulates and it would stay centered, but your stuffed tire would be more inboard than a suspension with a higher roll axis.

Picture a bar that just rotates about the center. The ends of the bar travel on a circular arc.

Now picture a bar that rotates about a point above the bar (say 12"). Now the center of the bar travels on a pendiulum arc as the bar articulates on a curcular arc. (kind of difficult to explain w/o a drawing). If you trace the ends of the bar as it articulates and rotates on the pendiulum, it will be more ellipitical.



Jack....nice work.

How much does your axle rotate (side angle) and how much travel does it have before it locks out (from backing plate to frame as a reference). I can't imagine you want too much more travel.

Don..part of this might be the picture. When we were cycling the axle through the entire range of motion, I was impressed with how little the pinion yoke was actually moving. The image below may help:
http://darkwing.uoregon.edu/~jrice/cruiser/FJ45/Suspension/4Linkalign.jpg
The yellow line is drawn from the TC output yoke to the center of the crossmember above the axle and then straight down. As Eric points out, the differential moves in an arc, so the rear of the diff will move side-to-side more than the pinion yoke.

Eric, I don't have the actual numbers on the side-to side movement, but will get them for you this weekend. The differential arc is really quite small. Moving the link hangers down to the crossmember and having all four in the same plane lowered the roll axis relative to the initial design. In terms of the vertical movement... measured from the inside bottom of the frame to the top of the axle housing, the total vertical travel is 15". Out where the tires are, of course, it is a lot more, and I doubt that I will want any more. But as noted in an earlier post, if I do, it is an easy fix.

WOW!!
What are the arms made from?
Whose heims?
Was it just me, or was BJ on Roids talking with himself awhile back?
As opposed to Mace , who plays with himself........

Butch

hey bj......


yes roids...wasssuuuuupp?? :flipoff2:

i am weird...you'll get used to it....

now:
if the upper two links, converged and the lower two links went straight up...then this would not work?

why not?
because i had this idea in my head, and thats sorta what i wanted to do..........

Hey BJ and Roids (you could be the next zaphod beeblebrox)
Have a look at my rear link setup when I see ya at tuff truck, It will do exactly what you want. Measured up my cousins FJ45 ute chassis and all the maths would transfer over from the Nissan set-up no worries. BJ40 chassis should be reasonably similar? maybe? Chassis width and crossmember positions and stuff....

depends, after 80, it will be similar, wither way.......ill give something a go and see what i get.....

It is 1980 model, drums on the front originally, front to back drag-link

the chassis design will be similar, but id rather fab my own links and arms and stuff up, id hate to use nissan stuff, as id rather scour my nipples off with a rusty steelwool pad, its not the nissans i have a problem with, there are a few around here who drive them and are a bit too arrogant

nah, It's not nissan stuff, just DOM and heims and stuff, works good. I can bring the steel wool up with me if ya want ;)

Thanks, Eric, Medusa. I'm beginning to understand.

Keep the pictures coming, this is a great project !

Hmmmm.....Nissan's ?

There's a lot of Nissans at the PNP

Butch.. The links are 2" schedule 80 pipe and the heims are cheap agriculture units. So cheap in fact that they don't even have a name on them -- just a "made in India sticker". They will get replaced as soon as they wear out.:D


if the upper two links, converged and the lower two links went straight up...then this would not work?

I am still not sure that I am understanding this Aussyspeak correctly, but I believe what BJ on Roids is describing would locate the Instant Center essentially right on the crossmember. I don't think that would work very well.

Jack, beautiful as always....sure are giving my lots of ideas for the rear of my FJ40....between the info you have on this project and the stuff I've been learning from Troy at the Badlands (Attica IN) I think I may dive into something myself this winter.

Many people set up the IC so that it is right at the COG. This helps eliminate the the rear end jacking (anti-squat) on the frame. If the IC is too far back, it will lift the rear of the frame, if it is too far forward, it will lift the front of the frame (or sag the rear of the frame = squat).

I can't get a picture looking perpendicular to the truggy because my workbench is currently in the way, so you will have to take my word for it. The IC appears to be located roughly at the center of the SM465. I think this will place it behind the COG and provide some anti-squat, but not so much as to cause problems. Again, I think BJ on Roids suggestion would place the IC too far aft.

ERIC, MEDUSA, OTHERS, DO YOU GUYS HAVE ANY GOOD RESOURCES OR BOOKS I CAN LOOK INTO TO LEARN MORE ABOUT SUSPENSION DESIGN AND INTERACTION? THANKS, MATT

Matt.. It is painful to read, but if you separate the BS, the God of Suspension Thread (http://www.pirate4x4.com/forum/showthread.php?s=&threadid=7503) contains a lot of useful information and references to some of the standard books.

Hey Jack,
Great job on your project. You are very inspirational! I have been following along, well actually, began by refering to your 40 buildup for several years, and knew this project would highlight your skills and techniques.

I personally have grown and learned along with many other POR members from you (and and others as well) and appreciate the virtual connection between us all. I have been so consumed in my own world of (beginners) competition wheeling that I haven't said much as I watched you, Nolen, Glow, Metalmender and others share their projects with us. I may be wierd but I feel like I know you guys, and the net (new phenomenon here) is bringing us all together in real time.

I am guessing we all like to interact with "like minds", with "like objectives". I've rambled enough, but I wanna get this out before I go on my goodie search this morning, Good Job to all, you guys have become (don't be afraid) my extended family!

Someday we have to have a reunion!

Originally posted by SpaceGhost

Good Job to all, you guys have become (don't be afraid) my extended family!

Someday we have to have a reunion!

THAT, is scary!

Jack...ditto what fuzzy face said!

Great work!

spaceghost, i'm with you 100%!;)

Originally posted by SpaceGhost
Hey Jack,
Someday we have to have a reunion!

Farmington?
I'll bring a case of the best beer that Vegas has to offer ;)


Oh and Butch


:flipoff2:


Yeah I play with myself but hell would't you if you if all you had to go home to at night was this???

http://imagem.webphotos.iwon.com/1000031835/1000031835_812200244456PM6.200153E-02.jpg

Originally posted by Jason M


Farmington?
I'll bring a case of the best beer that Vegas has to offer ;)




jason, skip the beer, bring them showgirls!

Thanks, Mike and all the rest of you as well. This new medium has clearly made a great difference in our hobby. Sharing of our triumphs and failures on the trails and in the shop is an added bonus. I think we have all learned a lot from each other. I would surely be up for getting together at some convenient location in the future.

With all your rear links converging to a similar line(cross-member, as this picture suggests) Do you anticipate a lot of anti-squat??

I'm new to link stuff so humor me please

http://darkwing.uoregon.edu/~jrice/cruiser/FJ45/Suspension/LinkHanger.jpg

The links intersect the crossmember, BUT the upper and lower links themselves do not intersect AT the crossmember. The point at which the upper and lower links intersect is imaginary and for my suspension lies in front and above the crossmember. This point is known as the Instant (or instantaneous) Center (I.C.). In my case, the I.C. appears to lie roughly at the center of the transmission. Anti-squat is a function of the location of the I.C. and also the center of gravity. Since I don't have a clue where the C.G. is going to be on the truggy when finished, I can't say much about the actual amount or percentage of anti-squat. It should have some anti-squat, but hopefully not too much.

Originally posted by Medusa
The links intersect the crossmember, BUT the upper and lower links themselves do not intersect AT the crossmember. The point at which the upper and lower links intersect is imaginary and for my suspension lies in front and above the crossmember.

Thanks for the clarification. That's what I couldn't tell from the photo. I have seen a suspension where the links themselves (plane for upper and lower) intersected at the t-case output. The antisquat was horrid on an incline resulting in poor performance. Your photo just doesn't do your set-up justice.

Fawkin newbie question: Will this design eliminate the need for a pan hard rod?:confused:

Originally posted by Kyle LePage
F(delete)n newbie question: Will this design eliminate the need for a pan hard rod?:confused:



Yes it will. If you design your link suspension properly, you don't need a pan hard rod. (Flame suit on)......Pan hard rods are for those who didn't design the suspension correctly for our application.

If you are running a straight 4 link (like street cars) there is nothing there to confine the axle so it is free to move side to side. That is why they use a pan hard rod.

With at least one set of the links triangulated, you don't need a pan hard rod because the geometry of the triangulated links is what prevents the side to side movement of the axle. With the triangulated links, if the axle tries to move side to side, one link is in compression and the other is in tension. Since the links are assumed to be rigid, they will not compress or stretch or bend so the axle can't go side to side. To help visualize this, make a triangle shape and with 2 sticks /\ and fix the two free ends so they can't move (like being attached to the outer axle brackets. Now try to move the apex (where the two sticks are attached together) of the triangle side to side. You can't!

Originally posted by Eric
Pan hard rods are for those who didn't design the suspension correctly for our application.

Or for 3 link suspensions like on FJ-80's....

Saaaweeet! Nice work! Nuther fawkin newbie question, what's the setup on the front of a TJ called? OK, besides "F'n Heap a bolts!" Never looked real close, but they flex well! I'll guess a three link?

Originally posted by Kyle LePage
Saaaweeet! Nice work! Nuther fawkin newbie question, what's the setup on the front of a TJ called? OK, besides "F'n Heap a bolts!" Never looked real close, but they flex well! I'll guess a three link?

What is up with the "F" word in your posts? :confused: We aren't like the other sections. Just say you have a question and we will try our best to answer it. :D


The TJ uses a 4 link with a pan hard rod (5 link). This is done to help prevent bump steer where you try to keep the pan hard rod the same length and in the same plane as the drag link.

Mike, Ill bring Canadian beer for you guys:flipoff2: