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  #1  
Old 09-16-2002, 05:42 AM
littlechief littlechief is offline
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did a search and couldnt find any post regarding coil suspensions so Ill ask and see what kinda feedback I get.
have been planning on changing my suspension this winter and currently custom coil / link suspensions seem to be all the rage around here lately. what are your thoughts on this kinda system? thinking that I might give her a go, have really good shop here that could fab it all up for me without having to give up my first born. seen these systems in action and for articulation etc seem to work awesome but Im concerned about them being more complicated, more things to go wrong as well as I am concerned about the links hanging down, thinking they may affect trailworthyness a bit. I like to use my rig on all kinds of trails, rock, mud, climbing , exploring etc. most things except high speed. Think that coils will really add to the uniqueness of the beast as well but dont want to waste my time on something that will be less then I really wanted. any thoughts??
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  #2  
Old 09-16-2002, 06:38 AM
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Frank in Norway Frank in Norway is offline
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Coil suspension is more complicated, but if you want real good articulation it's much better than leafs. You can create a leaf sprung setup that can articulate very well, thats true. But then you'll have too use very soft springs, and you will have to make some sort of linkage to reduce axle-wrap.
If the linkage for the coil setup is made from quality steel and given a proper placement, trailworthyness should be as good as any leaf setup.
This is only my opinion, others will surely have other thoughts.
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  #3  
Old 09-16-2002, 07:20 AM
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littlechief...
I have three different types of suspension in 4x4s that I own.. (A) Coil & coil over straight axles .(B) Torsion Bar & leaf over IFS & straight axles. (C) ’76 & 81 Wagoneers … IMHO all of these seem to have some advantages but for vehicles at 5000 lbs. Over all I’ll chooooze the Wagoneer.. Call me ‘old fashioned’ but call me at supper time… CUL… ds..
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  #4  
Old 09-16-2002, 10:05 AM
tuck tuck is offline
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if nobody else is going to speak up I'll chime in for the leaf spring crowd. Coil and coil over suspensions are super neato, and a lot of them have tons of flex, but I think leafs can get the job done.

Like Frank said, soft leafs need a traction bar/link, but other than that if you use long, flexy springs in a good location you will get enough flex, unless you're trying to win a RTI contest. Leafs are simple, cheap and easy to replace if/when you destroy them on the trail.

But if you like designing and researching, coil supsensions are cool. But I don't think their performance justifies the swap. Chris Durham, one of the top professional rock crawlers, still runs leaf springs all around, doesn't seem to bother him.
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Old 09-16-2002, 01:55 PM
Sycho15 Sycho15 is offline
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I don't think a coil suspension converson would be all that hard- Provided you've got the right tools.

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Research! I think the track-bar 3-link system up front and the triangulated 3-link system in the rear is the best way you can go.

Use coils and brackets from a full-size Ford Bronco or F-150. Lift coils will be easier to find this way and the front ends weigh about the same.

Once my Comanche is sold and I've paid off all my debts, I'm buying the rest of the tools I need to build the quadra-coil suspension for my Wrangler.

[ September 16, 2002, 07:56 PM: Message edited by: Sycho15 ]
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Old 09-16-2002, 02:15 PM
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Personally, i am a big fan of 1/4 ellipticals, i have yet to actually make 'em, but they have a major wow factor and flexy as hell.
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  #7  
Old 09-16-2002, 02:15 PM
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I would go with franks opinion to be honest. He has coil springs that he has set up himself. And I dont think they have failed him yet.

Plug rock buggies use mainly coils and coil over shocks for what they do.
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  #8  
Old 09-16-2002, 02:58 PM
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Are we talkin' a Three link, four link, or a five link coil spring suspension? If the killer deal you're getting is for a three link, It's crap. Pardon my french, but it won't twist, it won't flex but it will sure a h*ll break! Quick fast and in a hurry! With a four link, you'll flex and twist, but you're gonna' twist and flex on the hiway, in the driveway, and everywhere else you don't want to. The four link leaves the axles with very little control relative to the frame. With a five link(this is what baja race trucks, monster trucks, and alot of serious rock crawlers run) you will have flex and still have a decent amount of control at high speeds. However, you will pay out the poodey hole for a suspension setup like this and you will be getting a TON of lift, just to clear the suspension parts. Unless you plan on turnin' 44"s, I say stick with leafs. I raced a truck up in Washington and learned alot doing it. I tried to run a three link in the front and had it explode on me two minutes into the qualifying time trial. Thats when I started to get serious and checked out all the different suspension setups. Honestly, you will get more articulation from leafsprings(if you want serious articulation, go for a 3/4 eliptical setup) and more control with leaf springs for your money. I had National Springs in California make my leafsprings for my race truck, and using different stiffness springs for the different lengths(the longest spring was very soft and got progressively firmer as they got shorter) I got a suspension that could flex like nobodies business and could still take a jump without breaking and hardly any axle twist at all. Which ever way you go, just be smart about it and talk to people who have run different set ups. Obviously, someone who's only run a three link is going to say that they are the best, someone that's only run leafs is going to say that they are the best. Talk to some people that have run different setups and ask their opinion.
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  #9  
Old 09-16-2002, 03:09 PM
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I forgot, fi you do go for coil springs, I discourage coil-over shocks setups. It makes replacing the shock a PITA, and tends to gum up with mud quicker too. Also,*****74Wag***** if you want any tech refferance for the the 1/4 elicticals, e-mail me off list and I'll be happy to help anyway I can.
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Old 09-17-2002, 03:07 AM
littlechief littlechief is offline
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thanks for all the good info guys, knew I could count on you Ive just recently started thinking about coils so it is not set in stone yet. Im off the mindset to try and keep everything as simple as possible which Im not sure that coils does. The fellow that would do the designing for me started building coil suspensions 12 years ago and has been refining them ever since. He took a break from the offroad scene for a few years and is now back into it with a new shop. He is a great guy, really knows his stuff and we were thinking maybe using my truck as a display/promotion for his shop. whats this about the elliptical springs?? what are they about? im still thinking about the modified stock springs as being the easiest to work with and the most bang for my buck, at least till Im convinced that the coils are all that and more. thanks for all the replys and keep em coming
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  #11  
Old 09-17-2002, 12:07 PM
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Hey LittleChief! All the different eliptical springs are kind of crazy and are best described with pictures, but since I don't have any, I'll do my best to explain. A regular leaf spring is actually a half eliptical spring, meaning it's half of an elipse(and elipse looks like a circle that has been streched). A 1/4 eliptical spring looks like someone flipped a leafspring over and mounted one eye to the axle and the other to the frame. It's super flexy, but not very stable or strong, so alot of people set it up so it looks like a four link or five link, but the top links are the springs. I don't beleive that 1/4 eliptical suspensions are street legal anywhere on the continent, but I could be wrong. a 3/4 eliptical suspension is a regular leaf spring, mounted to the frame towards the center of the rig with a bushing, and to a shackle towards the ends of the rig. BUT instead of the shackles attaching to shackle mounts, they attach to 1/4 eliptical springs. This sutup provides results similar to revolver shackles, except they don't"UNLOAD" uncontrollably. They provide resistance when they droop, which provides more control, on and off road. Also, you can't really tell a truck with 3/4 eliptical springs unless it's flexing, so it's easier to get away with running on streets with them, even if they are illegal, which I'm not sure they are.
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  #12  
Old 09-17-2002, 01:34 PM
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Here is a 1/4 Elliptical setup on a Scout
http://www.dandcextreme.com/buildup/pro2/day10.html
Some of the other days also have quite a bit of info

Here is a 3/4 Elliptical (aka Buggy Spring) setup on a Wrangler. I am currently working on making one for my Wag.
http://www.off-road.com/jeep/reviews...l/3_4elli.html

[ September 17, 2002, 07:41 PM: Message edited by: 74 Wag ]
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  #13  
Old 09-17-2002, 03:57 PM
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a soft or firm ride doenst neccessarily have anything to do with leafs or coils. you can have very stiff coil springs as well as leafs. for good articulation youll want a fairly soft spring rate. either system can be a winner if designed properly,however,methinks theres alot more stuff to break in a coil-sprung rig,and ther results are more catastrophic when they do break. my xj freind took out his coil sprung suspension and repaced it with simple,durable leaf springs after almost breaking both his upper control arms in half

the coolest thing about a coil spring suspension is the ablilty to put the axles at the extreme ends of the vehicle. its pretty cool to have approach/departure angles of OVER 90* [img]smile.gif[/img]
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Old 09-18-2002, 05:37 AM
Sycho15 Sycho15 is offline
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Quote:
Originally posted by WagoMonkey:
Are we talkin' a Three link, four link, or a five link coil spring suspension? If the killer deal you're getting is for a three link, It's crap. Pardon my french, but it won't twist, it won't flex but it will sure a h*ll break! Quick fast and in a hurry!

I've got to disagree here, there are probably a couple million vehichles out there running 3-link coil suspensions that hit the highways and run the Baja races. How about the FORD BRONCO? It's only got 3 control arms: 1 track bar and 2 radius arms. ****, those things take a beating, flex great, ride well, have stability comparable to a Grand Wagoneer any day.

The TJ/MJ/XJ/ZJ Long-arm kits produced by almost half-a-dozen aftermarket suspension manufacturers effectively turn the front (and where applicable, the rear as well) suspensions of these vehichles into 3-link systems. They're kicking *** on the trail and many people use those vehichles as daily drivers.

With a four link, you'll flex and twist, but you're gonna' twist and flex on the hiway, in the driveway, and everywhere else you don't want to. The four link leaves the axles with very little control relative to the frame.

Can you say anti-sway-bar?

With a five link(this is what baja race trucks, monster trucks, and alot of serious rock crawlers run) you will have flex and still have a decent amount of control at high speeds. However, you will pay out the poodey hole for a suspension setup like this and you will be getting a TON of lift, just to clear the suspension parts. Unless you plan on turnin' 44"s

Again, there are millions of vehichles running around with small tires and 5-link coil suspensions. The MJ Comanche, XJ Cherokee, ZJ and WJ Grand Cherokees, and the TJ Wrangler are just Jeep's offering of vehichles with this suspension. I've got a 5-link coil spring suspension in the front of my MJ and it sits so stinking low that the biggest tires I can fit are 30x9.5s.

I say stick with leafs. I raced a truck up in Washington and learned alot doing it. I tried to run a three link in the front and had it explode on me two minutes into the qualifying time trial.

Did you build this three-link by yourself?

Thats when I started to get serious and checked out all the different suspension setups. Honestly, you will get more articulation from leafsprings(if you want serious articulation, go for a 3/4 eliptical setup) and more control with leaf springs for your money. I had National Springs in California make my leafsprings for my race truck, and using different stiffness springs for the different lengths(the longest spring was very soft and got progressively firmer as they got shorter) I got a suspension that could flex like nobodies business and could still take a jump without breaking and hardly any axle twist at all. Which ever way you go, just be smart about it and talk to people who have run different set ups. Obviously, someone who's only run a three link is going to say that they are the best, someone that's only run leafs is going to say that they are the best. Talk to some people that have run different setups and ask their opinion.

I'm a bit surprised that you prefer leafs over coils for racing, what with the weight savings of coil springs, their ability to be moved to the extreme ends of the vehichle thus increasing your wheel-base and ensuring that you'll land on your tires and not your bumper if a jump was taken badly.
I'm going to be putting coils all the way around on my YJ Wrangler (Trac-bar 3-link front, Triangulated 3-link rear. Front and rear sway-bars) just as soon as I can get the Comanche sold and buy the required tools. To be sure, I'll let you all know how this works out.

I'm most likely going to stick with leaves all the way around on the J-10 though, since it won't be as "extreme" a vehichle.
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  #15  
Old 09-18-2002, 03:25 PM
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i dont know id say ford broncos flex good. ive seen some fords that the whoel truck leans when driving on something,instead of the suspesion flexing this is more a prollem with spring rate,not neccessarily a prollem with 3 link suspensions,tho.

i can certainly appreciate the engineering and work that goes into coverting a multi-link coil sprun suspension, but in my jeep ill stay with simple leaf springs that spring the vehicle and locate the axles.if youre keepig the wheels in their relative spots in the wheelwells,i cant really see any benefit from the required work,and increased "breakage factor" of multiple links.

i would someday like to build a custom tube chassis vehicle with coil springs,and the axles at extreme ends of the rig.

that will happen as soon as another set of $200 rockwell axles appear in the trading post ill get them and build a vehicle around them. [img]tongue.gif[/img]
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Old 09-19-2002, 12:45 AM
krob725 krob725 is offline
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i agree with the coil spring guys. i had a XJ with a small lift and it had tons of wheel travel. i later traded it in on a 89 YJ and it had about an inch of travel. i hated it. if i could put a coil setup on my GW like the XJ's have i would do it. maybe your freind could come up with a "kit" like they now make for CJ's and YJ's.
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Old 09-19-2002, 02:44 AM
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thats not a real fair comparison,tho,unless youd removed the sway bar and front/rear trac bars on the yj. doing this will bump the stock RTI frmo around 400 to almost 800.

god articulation doesnt have anyting to do with the type of springs. it has more to do with the rate,and you can set up a leaf or coil spring up to have good wheeltravel if thats what youre after.

as was mentioned,when using a real soft leaf spring,extra links can be needed to help maintain good road manners at speed,making them not alot different than coil setups.

you can do some real funky stuff with leaf springs-1/4 eliptic,3/4 eliptic,transverse mounted leafs. i tink a properly setup 3/4 eliptic will gave waaaay more wheel travel than any coil spring setup.

again,the biggest advantage is being able to keep the wheel/tire at the extreme end of the vechicle with coils

all can systems can be good or bad,and the key to any setup is making everyting work together and setting it up for how you drive it.and building it about 3 times as strong as you think it should be

ur thots [img]smile.gif[/img]
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Old 09-19-2002, 02:46 AM
Sycho15 Sycho15 is offline
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My stock YJ actually had pretty good articulation. I installed 4"-extended brake-lines, removed all sway and trac bars, and the shocks and spring clamps became the limiting factor. It stuffed the 31s into the fender far enough that it bent the fender lip and cracked the little reflector light there.

Before I lift it, I'll loosen up the spring clamps, unbolt the shocks, and ramp it up something at the local park for a good poser flex picture.

I'll do the same to the Comanche before I sell it, I'll remove all the limits to the stock suspension and ramp it for a picture.
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Old 09-19-2002, 05:46 AM
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There is nearly as many opinions on what's the best suspension setup as there is members on this board. I don't want to argue about what's the best setup, but I'd like to say something about what suspensions is supposed to do.

To make the springs do their best, you'll need the softest spring rate that will hold the weight of the truck without bottoming out. A stiff spring will not be able to move the wheel up and down fast enough to keep the wheel in contact with the ground and the result will be lost traction. Also a stiff spring can't articulate well in an off-road situation. So with this beeing the best, why don't the manufactures use very soft spring on their trucks?
There are several reasons. Stock vehichles are designed to carry various kind off loads, and need a spring rate that's stiff enough to carry the vehichle when it's fully loaded. Also, softer spring rates needs more axle control to avoid excesive body roll when you make a high-speed turn. Which leads to the shoch absorber.

When a spring is compressed and then released (driving over an obstacle) It will take a long time to stop moving, so if your suspension system is just the springs it will undriveable. And using soft springs makes things even worse. Here comes the shock absorber. This is a tube with a piston and a rod in one end filled with oil to dampen the spring movement. A perfect absorber will let the initial spring movement pass and then it will stop the movement when it isn't needed anymore. It has to know what's coming next to do this job perfect. As we all now this isn't possible, so some sort of compromise has to be used. Manufactures do use various kind of internal valving to let the shock move more or less quickly based on the speed and lenght off the movement. If the shock is too stiff it will destroy the advantage of a soft spring rate and if it's to soft it will not do it's job.
There is also several shock that has external adjustment of the valving, so that the stiffnes can be adjusted without changing the shock.

When driving slowly over obstacles, a very soft suspension system will let the wheels articulate and makes sure that you obtain all the available traction. However, if you drive faster you'll need more and faster control over the wheels and axle.

To further complicate things the suspension system also needs to locate the axle...
The perfect located axle will move up and down without any front/rear or rotating movement.
If the suspension system is a leaf spring setup, the springs are used both to locate the axle and let it articulate. This makes a very simple setup, and it works quite well. The leaf springs used in the factory setups are usually very stiff to avoid axle wrap and to locate the axle sideways. If you want to make a softer suspension with lots off articulation using leafs, you'll soon run into axle location problems.
So you'll have to make some sort of axle location rods to keep the truck handling well at speed. Also to avoid driveshaft destroying axle wrap.

If you are using coil springs, 3/4 elliptical, air-bags or any other setup where the spring itself don't locate the axle you have to fabricate some sort of linkage system. The most populare are 3, 4 or 5 link systems.

3-link systems usually are made of two rods on the bottom off the axle and one on the top. This makes a good job locating the axle front/rear, but it don't do anything for the side to side movemenet. I've seen setups that has been called 3-link that has an triangulare upper link that has one mounting point at the axle and one on each frame rail. This isn't a 3-link system, but actually a 4-link system.

4-link systems are made of two rods on the bottom of the axle and two on the top. This won't locate the axle sideway, unless you move the upper (or lower) rod to a central mounting point on the axle or the frame. This is also called a K-link.

5-link systems are usually 4-links with a panhard rod going from one frame rail to the opposite side off the axle. The will make a good job locating the axle sideways.

And then there is the setup that Ford and others uses on their front axle. It has one radius arm on each side of the axle going to the frame together with an panhard rod locating the axle sideways. This are not a true 3-link because the radius arms won't let the axle rotate, so it's more like two arms on either side combined into one.

All of the linkage system above can be used with coils, airbags and 3/4 elliptic.

If done right any kind of suspension setup will be as sturdy as the other. Leafs and brackets for leafs breaks just as easy as coil-spring linkage if it's not doen right.

But, when it comes to designing a good suspension system, you have to make up your mind what you want your FSJ to do.
The best setup for desert racing is not the best for slow speed crawling. And when you hit the highway at 75mph you will need a supension thats firmer than your articulation champ. The best compromise would be a flexible suspension with either coils or leafs with an removeable swaybars and adjustable shocks.

Sorry about the very long post, but suspension design is very complicated, and I haven't even began to talk about steering and suspension geometry )
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  #20  
Old 09-19-2002, 07:09 AM
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Quote:
Originally posted by Frank in Norway:
[QB]Stock vehichles are designed to carry various kind off loads, and need a spring rate that's stiff enough to carry the vehichle when it's fully loaded. Also, softer spring rates needs more axle control to avoid excesive body roll when you make a high-speed turn. Which leads to the shoch absorber.QB]
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Very nice Frank... May I add to your statment.. "avoid excesive body roll when you make a high-speed turn.""
In the front a strong spring rate can help prevent rollovers in offcamber conditions if the front swaybar is strong and still connected. And when used with a light spring rate in the rear, plain HD rear shooks and no sway-bar, can still have a nice amount of flexing and yet high speed control. I don't 'air-down'(much) or disconect the sway-bar. This concept is cheap and works well on my 2" lifted Wagoneer.
CUL... ... ds..
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