4 link rear suspension

[AJ Johnson]

I need help designing a 4 link rear setup guys..
also, I need to find a place to get the nice coilovers for it..
any one know a bit about making a 4 link?

[80258WT]

i had great sucess searching the pirate4x4 board for a bunch of pics and designs. BUt buy the milkens suspension book for the formulas. THere are many places to get some coilovers but there are some on sale for 200 each from www.polyperformance.com (http://www.polyperformance.com) and some place called bent and twisted.

[rockjeep44]

try searching, there is some good info in this forum as well
http://www.ifsja.org/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=16;t=000004

[David Allen Racing]

Look for a local race car fab shop and see if you can pick their brains a bit. They may have some good ideas for ya.

Dave

[dnixon]

Originally posted by 80258WT:
i had great sucess searching the pirate4x4 board for a bunch of pics and designs. BUt buy the milkens suspension book for the formulas. THere are many places to get some coilovers but there are some on sale for 200 each from www.polyperformance.com (http://www.polyperformance.com) and some place called bent and twisted.About Dave from polyperfomace you have to mention you saw the add for the 2" (diameter ;) ) coil overs on the pirate webpage. But you can call him directly. he will also do spring calcs free of charge if you are able to give him info on your rig.. but also check the link the RJ44 put up it was a pretty good post... Good Luck..

[orangecherokee]

why are you going with a 4-link? what are you looking to do with your rig?

[Elliott]

Ran across this AJ: http://www.truckn-store.com/product.asp?returnURL=default.asp&ID=22749

[tuck]

pirate4x4.com/forum

search for the god of suspensions thread and start reading. there is so much information there. if you're serious, I would look into triangulated 4 link, similar to the one that is posted for sale above..

Petersen's 4wheel magazine has done a couple articles on how to setup a triangulated 4 link, and it's pretty good from what I can tell...

like orangecherokee said, what's your reason for wanting 4 link? There are a lot easier ways to get lift or flex...

4 links tend to require homework, geometry, and research/know how, and after that it seems to be trial and error till it works right... if it ever does work right. :D

[DieselSJ]

Why all the questions about "why"?

My question is why would anyone want to base a serious trail rig on something so limiting as a leaf spring? Yes, it is easy to bolt in a leaf, and any monkey can do it, while a 4 link takes some brains to design. But, a 4 link is so vastly superior in what you can do with it, why do you bash anyone that wants to use one?

[robselina]

Originally posted by Mark in WA:
Why all the questions about "why"?

My question is why would anyone want to base a serious trail rig on something so limiting as a leaf spring? Yes, it is easy to bolt in a leaf, and any monkey can do it, while a 4 link takes some brains to design. But, a 4 link is so vastly superior in what you can do with it, why do you bash anyone that wants to use one?Yea, gotta hate those limiting leaf springs :rolleyes:

http://www.rebelrockrunners.org/gallery/chopshop/mcnair/images/andrewflex2.jpg

As Andrew shows above, you can get PLENTY of flex from a leaf.
I don't think anyone here is really anti-4link, it's just that there's a process to all of this. You don't go putting rockwells under your heep as a first mod. In this case, you probably need to do a couple of leaf sprung suspensions, play with 3/4 eliptics and the like before going there. a 4 link requires a lot of knowhow, fabrication skill and trail repair capability. You also need to be willing to make 3 different setups to get one "right". It doesn't just fall together and work. All anyone was asking was for his motivation in doing so, trying to figure out if it's right for him or not.

[ September 16, 2003, 11:54 AM: Message edited by: rselina ]

[tuck]

Mark, while leaf springs aren't all that limiting when used correctly... I agree that link suspensions can offer more travel, better ride, and better traction.

I am certainly not bashing anyone who wants to use a 4 link. I'd love to go link'd front and rear myself. But I certainly don't recommend that everyone start building their own link setups... they can be scary dangerous, and in a lot of cases leaf springs will get the same job done for a lot less $$...that's why I ask all the "why's"

I wasn't trying to bash anyone..

[orangecherokee]

Originally posted by Mark in WA:
Why all the questions about "why"?

My question is why would anyone want to base a serious trail rig on something so limiting as a leaf spring? Yes, it is easy to bolt in a leaf, and any monkey can do it, while a 4 link takes some brains to design. But, a 4 link is so vastly superior in what you can do with it, why do you bash anyone that wants to use one?Have you ever set one up? not trying to call you out but just wondering your level of expertise on the matter. i've personally never set one up but i've done a $hit-pot full of research on the subject. i feel you can get great travel from a leaf sprung set-up. just look above at RJ44. i've seen it in action and i never saw a short coming except for the tires ;)
there's a lot more than just a simple bolt on and rock out package. it takes more math than a GRE exam can hurl at you plus the money involved can put some men in the poor house. i'm not saying it can't be done by AJ but i think we're just looking out for his interets. i'm not anti-4link, i wish everyone could have one.

food for thought... i want an 80 gallon fuel cell, should i get it???

[fsj1978]

Good lord man, 80 gallons, where are you going to put it?!!!!!!!

As for 4 links, I don't think they require quite as much math as you think... A friend of mine built a Willys with front/rear 4 link / air bags and as far as I know, he didn't do any math at all.... But he DID wind up doing a lot of trail fixes with his onboard welder (gawd send!!!!!) for about 1-2 years after he first got it on the road.....

I really don't know what the BIG draw is from a 4 link, especially if you use a track bar like my friend did. When you have a track bar and lots of suspension movement, that axle moves left/right a *LOT* even if you've got a reasonably long bar.

I didn't check out the link that someone was talking about as far as a "triangulated 4link", is this kind of like the older GM products that had the two lower bars parallel to the frame, and the two uppers went from the pumpkin (close to centered) out to the frame to control lateral movement? This is definately the way I'd go if I were to ever do some kind of coil or air suspension.

Another thing to think about: How much flex do you actually need??? Other than for 'ramp index' purproses? Are you going to do major rock crawling where you need the flex??

I'm not really for, or against any particular suspension setup (though I'm starting to dislike IFS setups), it comes down to
1) How much engineering / construction can you do yourself?
2) How deep are your pockets?
3) How long do you want to be w/o your rig?
4) How much trail fixing are you capable of?

I don't post too much, but when I do they're loooooooong!!!!! (is this a bad thing??????)

[DieselSJ]

Yes, I have actually set up several of them. Back in the late 80's and early 90's I was very active in desert racing (lived in San Diego) and was involved with building a couple trucks from the ground-up. I also worked for an off-road shop for about 5 years and we did several conversions for customers. In fact, the team I used to race with is still running a Class 800 F150 and our 4-link/coil rear is getting 30" of travel. Before you say "30 inches, big deal", that is 30 inches straight up and down, and we have an articulated difference of almost 40 inches, with the frame level. Let's see a leaf do that.

A 4-link really isn't that hard to design and build. You do have to have some fab skills, but if you can do a SOA and crossover steering, then you probably have the mechanical skills necessary. People get into trouble when they use cheap quality stuff, have crappy welding skills, or don't do the proper research (then again, those guys will get into trouble no matter what they build).

But, that is just my opinion.

[rockjeep44]

Originally posted by Mark in WA:
Why all the questions about "why"?

My question is why would anyone want to base a serious trail rig on something so limiting as a leaf spring? Yes, it is easy to bolt in a leaf, and any monkey can do it, while a 4 link takes some brains to design. But, a 4 link is so vastly superior in what you can do with it, why do you bash anyone that wants to use one?Only reason I'd like to know why is because I know a hella lot about 4-link suspensions and I don't want to waste my time explaining one in detail to someone that isn't serious about actually building one. Not saying that is the case, just want to make sure. If he really plans on going 4-link I'll break out the knowledge.

I'm going 4-link front and rear on my buggy and acknowledge that one built correctly in conjunction with coilovers or coils setup with the PROPER spring rates is far superior to any other suspension setup but that is a lot of "ifs" and it is true that leaves can be setup to work Great Googley MoogleyGreat Googley MoogleyGreat Googley MoogleyGreat Googley Moogley well very easily. Just look at Chris Durham's rig...if you don't know who he is don't ask.
-Andrew

[BobWilliams]

I run leafs on my crawler with king 2.5 16" shocks and it flexes and works great. people always ask why I run leafs if I already have the kings? if you know how to build a badass leaf suspension that has proven itself everytime at an event or on the trail then you would know the answer. not to bad mouth 4 link because I have a desert truck that is linked w/king coilovers. its the simplicity of not worying about suspension failures on the trail.

[80258WT]

so you have a leaves and king coilovers for shocks? Why?

ANd BTW whoever said they had 30" of drop with the frame level, i'd like to know more about your link set up, thats insane. What was it a double wishbone or something?

[DieselSJ]

More about our link setup...

It is a true 4-link. We had used a single "y" style upper arm for a while, but had problems with that so we reworked it to use 2 separate upper arms. Basically, lower arms go from frame to front of housing (at the ends), uppers go from frame to the top of the pumpkin. IIRC, the lowers are about 65" long. The coilovers attach to the lower arms about 18" in front of the housing.

[rockjeep44]

I kinda like those setups where the coilovers are attatched for the lowers. What did you use for mounting points on the lowers at the axle end?

[DieselSJ]

Big heims...