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progressive rate coils?

72k5mike

72k5mike

1/2 ton status
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Hey guys

I have just finished my 63" rear spring swap and it was worth every penny and all of the cuts (removing factory hangers is a PITA!)

I am currently planning a front radius arm conversion. I have the ballistic coil buckets and axle brackets and I was wondering if I can pick some minds....

I want to do progressive rate coils, anyone have any experience with the duff or wild horses br*nco progressive rate coils? any objections to either or the idea of progressive itself?

I am leaning toward progressive because I mostly do street/beach driving so most of my wheeling is over lets say 20mph. I already have 14" travel bilstein 5150s in the firmer valving. What do you guys think?
 
They will work fine, I have actually used those on a couple of different trucks. They will be a bit soft but a sway bar can cure that, or you can just get used to it.

Now I realize the radius arm suspension is pretty simple and easy to do, but can I ask why that. In the end it will end up limiting your overall travel somewhat. Which is not always a bad thing. Why not a 3 link up there with 2 lowers (or uppers) and one upper (or lower) That will not limit stuff at all and will let you adjust the numbers a bit.
 
The radius arms that I want to go with are similar to the long arm kits for TJ's and the grand cherokees where I would have a stout lower arm and the upper link would mount to the center of the the lower arm. The upper arm would be totally adjustable to change camber. The lower arm would be have a flex joint in the rear so I could move the axle slightly forward or backward. I figure for some extra flex I could disconnect one of the upper links (to mimmick a wristed setup)...

any pics to a 3 link?
 
I just finished the same thing you are talking about, and with one bolt of the left upper link removed, I could articulate it the full 14" travel of the coilovers in the garage with ease and no binding, which was further out at the wheels when articulated. It pleasantly surprised me, I had to clearance stuff a lot more than I had planned. I had to get the shock changed to remote rezi because the tire articulated so much it came up and hit the piggyback rezi, and I only have 36" tires on about 6" of lift. So I haven't had a chance to test it offroad yet, but the onroad test it handled great and steering was MUCH more precise than with the crossover and leafsprings. Also, full 14" travel of the coilovers was no problem, if my driveshaft and steering joints could take the angle, more travely was easily doable with the radius arm itself.

My radius arms connect to the frame with 3" ballistic joints, and to the axle with bushings. The upper arms are bushings at the axle, and 7/8" heims at the lower arm, to keep it skinny for more turning radius. Also, those don't really move anyway, it is just for pinion angle and wristed possibility that I put the heims in. The track bar is a 2 5/8" ballistic joint at the frame end, and a 7/8" heim at the axle end because there wasn't enough room for the ballistic joint with both upper and lower arms, the pumpkin, the coilover, track bar, and draglink all connecting in the same area on the passenger side.

Also, I thought about the 3 link, but with the adjustable radius arms I could keep my long tube headers (block having a more centered upper single link), and my turning radius (which is reduced if you have dual upper links outisde the frame rail). And for the street with both upper arms it handled rather well for the soft dual spring rate I had, even during cornering.

The only downfalls are if you want full flex potentail, you need to take a bolt, or one whole short upper arm out. Also, you can't adjust you IC other than where you attach the radius arm to the frame. I think the pros outway the cons, unless you are a dedicated rock crawler. I can't wait to try it out offroad.
 
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I'm running the progressive coils in the back

I'm happy with them
 
Well, I don't want to hijack the thread, but I did use dual rate coils, and I thought they were fine on the road, with the radius arms and no sway bar, even with the inital rate of less than 200 lb/in. (I have 450 over 300 lbs/in.)

Also, I still have to finish some things up...

- cut to fit the inner fenderwells
- cut off excess stabilizer ubolts and shock bolts
- cut out and weld in the engine cross bar removal flanges
- hook up longer vent hose
- cut off factory front spring hangers
- reinstall shocks after they get back from being remote rezi shocks
- etc.

All I have so far is crappy cell phone pics, my wifes good camera broke, waiting for it to come back from service. My first custom suspension, so don't be too hard on me. All of my other suspenion installs have been bolt on stuff.

front l.jpg

front r.jpg

engine.jpg

left shock.jpg

right arm.jpg
 
More crapp cell pics of some mockup stages, articulation with one upper arm removed...

Also, I don't have a tubing bender, so my friend Jer (dunejump) helped me out with the tubing bigtime.

right shock.jpg

wheelwell l 2.jpg

L art.jpg

F art.jpg
 
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Thanks for the help guys, and folkenheath.... Hijack away man, were all here to learn. And how long are your arms? would you go longer if you could?
 
My arms are under just under 44" (sounds so much better than 43.5") center to center.

I am not sure on the longer arms yet, haven't had enough time to test them out. I was going to make them even with the crossmember (stock TH400/NP205 adaptor), but decided to modify it so the arms could be several inches longer. Right now they are just under the frame rails at the rear, I need to get it offroad once I get the shocks back. I think if I went any longer, I would have to start inboarding them inside the frame to keep the same lateral angle, because I wouldn't want to limit my steering angle. Currently at full lock (from factory), it was just rubbing with my 36x14.5" TSLs(the largest of the 3 lugs). So I turned the stops in so I have just over 1/8" clearance at full lock. That's with 2" x .250 wall DOM tubing, mount just outside the D60 leaf spring pad (with 3" wide bushings), and matching width on the drivers side.
 
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If one radius arm and one lower link on the other side achieves the same thing as a 3link for locating the axle then why cant it simple be ran like that?

I know dodge guys with radius arms pull the upper off one side and say it hardly affects street driving.
 
Well, it could be driven like that, I haven't tried it yet. But it might act abnormal under braking if it wants to twist the axle crooked under force since you are only controlling twist on one corner, maybe it won't be enough to matter though. I'll find out sometime, right now I am just looking forward to getting it off road. You are right though, an offset 3rd link could have the same effect. The only difference is you can adjust your IC with the seperate 3rd link, which I don't think is near as important as the back (antidive instead of antisquat).

I also think the bind associate with it is kind of like a built in sway bar for street driving. But maybe it will handle fine with just one upper arm, I don't know yet. It all depends on how much bind you have.

And k5Mike, keep in mind also other factors will effect your handling and articulation in addition to radius arm length and spring rate. Including the bushing seperation distance at the axle, bushing material and durometer, bushing width (to a smaller degree, if it increases deflection resistance), etc. It's a compromise, better cornering on the street (or high speed offroad), or more articulation for low speed crawling...
 
folkenheath said:
Well, it could be driven like that, I haven't tried it yet. But it might act abnormal under braking if it wants to twist the axle crooked under force since you are only controlling twist on one corner, maybe it won't be enough to matter though. I'll find out sometime, right now I am just looking forward to getting it off road. You are right though, an offset 3rd link could have the same effect. The only difference is you can adjust your IC with the seperate 3rd link, which I don't think is near as important as the back (antidive instead of antisquat).

I also think the bind associate with it is kind of like a built in sway bar for street driving. But maybe it will handle fine with just one upper arm, I don't know yet. It all depends on how much bind you have.

And k5Mike, keep in mind also other factors will effect your handling and articulation in addition to radius arm length and spring rate. Including the bushing seperation distance at the axle, bushing material and durometer, bushing width (to a smaller degree, if it increases deflection resistance), etc. It's a compromise, better cornering on the street (or high speed offroad), or more articulation for low speed crawling...
Click to expand...


Well as far as the braking and uneven forces I'm thinking about doing a pitched 3rd link that goes to a more centrally located mounting point on an angle. I think this is the key to a simple setup, no binding, and good street manner in one package.
 
Adventurous 4x4 said:
http://whaleyent.com/v-web/gallery/album06
Click to expand...


Yeah like that but with a single lower link on one side.

I know the front end is suppose to unload really easy with a setup like that but a simple center limiting strap can fix that easily.

I would think with the upper link pitched toward the axles center would solve any hard braking issues inherit with the caster being controlled on the extreme left or right with a traditional RA.
 
Stomis said:
Yeah like that but with a single lower link on one side.

I know the front end is suppose to unload really easy with a setup like that but a simple center limiting strap can fix that easily.

I would think with the upper link pitched toward the axles center would solve any hard braking issues inherit with the caster being controlled on the extreme left or right with a traditional RA.
Click to expand...

It's where the arm attaches to the frame just as much as where the arm attaches to the axle. If the arm is not centered on the frame, then it will lift one side more than the other during braking (for the front). However, if your IC is further back it will be less evident.

Also, you may want a sway bar for that on the street, you won't know until you try.
 
Folkenheath, That looks like a really cool build:waytogo:
You really should post a build thread for it.

Or do you have one, and I've missed it?
 
folkenheath said:
It's where the arm attaches to the frame just as much as where the arm attaches to the axle. If the arm is not centered on the frame, then it will lift one side more than the other during braking (for the front). However, if your IC is further back it will be less evident.

Also, you may want a sway bar for that on the street, you won't know until you try.
Click to expand...

IC = Inner Control Arm?

So your saying the farther back I mount the Inner/Upper control arm on the lower and the further in toward the center of the axle it is the less noticeable it will be?
 
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