Control arm basics - can someone explain the basics and why adj would be needed?

I am unfamiliar with coil suspensions. I understand why the control arms are there, they allow the axle to move up and down, and, if I'm correct, you'd want extended arms when you lift to allow the extra length you'd need, right?

I'm lifting approx. 6" with a 4.5" coils/leafs and spacer/shackle. I believe the kit comes with lower arms, but will I need upper arms, or should I replace both. Do I need adj. arms, or why would I need adj. arms? How do I know what control arms I need and what are the differences?

Thanks, and I'm confused on this aspect.

First what kit are you going with at 6 you are going to need adj uppers and lowers or at least lower arms made for 6 inches of lift not 4.5 and also at 6 I would recommend going with drop brackets for the lowers or going long arm?

I was looking at the RE kit. There are so many kits out there, it confuses me. I was set on the RE kit, but then I found a Rough Country kit priced right, although, I don't think its near the quality of the RE kit, so I'd stay with the RE kit over the RC. Then Summit Offroad is selling the OME 5" kits but they don't include replacement control arms.

What confuses me is this comment they made on control arms:

Almost as bad as poor quality springs nowadays are "long arm" kits. This kits do not allow your front axle to cycle up and down in the manner it was designed for which is why they ride so terrible at highway speeds. Long arm kits are fine for vehicles trailered to the trails. If you want to keep your vehicle and passenger's safe though, stay away from this latest fad as the rotating castor on these systems makes for screwy handling and you will curse the day you wasted money on it.

Click to expand...

So how accurate is that statement???

It doesnt make sense to me how can it not allow the suspention to cycle properly. Where is his evidence I could say that I have more stablity when I have 8 inches of lift then when I am stock is that true no but it must be true because its on the internet

It's exactly the opposite of what everybody else that has long-arms has posted here, and it doesn't make logical sense. The radius of the arc is wider with a long-arm kit, so your axle doesn't move back as far with the long-arm kit as it cycles down during articulation, which keeps your springs more in line, gives you better control-arm angles, etc. Caster changes, but not enough to matter at high speeds on the road because the movement is minimal, and not enough to matter off-road because it is slow movement when you get extreme flex.

Caveat: I do not run long arms.

Personally, I'd say that the above quote is rubbish.

What I've picked up here (and other places) over the last couple of years is:

0-3": stock control arms, trackbar, steering
3-6": new lower arms and trackbar. stock steering and upper control arms
6+": all new control arms, trackbar and steering.

Obviously, different strokes for different folks.

The long arm guys crow about the on-road manners. I suspect that what makes it good is that the arms are closer to horizontal. At 6" of lift and the stock control arm mounts, the arm angle is quite steep compared to a stock arm. And the axle will actually move forward a little under compression.

Another option is to run drop brackets with tall lifts to partially correct the control arm angle issue. Like long arm mounts, it's something else under the body to hang up.

Caster change under suspension movement? Uh, under highway conditions, I suspect the caster change will be less than the allowable range for caster adjustment.

Hmmmm... Summit Offroad? http://www.summitoffroad.com goes to Rocky Road Outfitters now. http://www.summitoffroad.net is a motorcycle parts shop.

Well, I saw that comment and it just didn't sound like what I was learning elsewhere, so I wanted you guys to take a look. The common sense reasoning of going higher means your axles move backwards, or control arms less horizontal, thus the reasoning of longer control arms.

I apologize, it was Rocky Road Outfitters, here's a link to the suspension page.

Is it best to find a "kit" without control arms and buy ones fit for your needs, or is it best to find a kit with the arms for that kit?

There IS a shred of truth behind some of RR's long arm comments......

Most of the long arm kits I've seen are better described as mono-arm kits. The axle is prevented from rotating (using the LCA mount as a pivot) by a triangulating arm that goes from the stock UCA mount on the axle to a mount placed back on the long arm. There is some discussion about free motion with this type of system when 1 side goes up and the other goes down.

Whether you got with a kit, or match up your own components is up to you. I'd say that if you aren't familiar with all of the parts, getting a full kit may be a better bet. Just remember, kits are frequently not "complete" unfortunately.

Complete kits aren't usually "complete", but the stuff they do have usually all fits together properly, proper control-arm lengths for the springs if they're not adjustable, etc.

Lets just say that at about 6" and up you will need to do something about the stock setup.That could be drop brackets,midarms,longarms,etc..I just recently did my LA's,my buddy took my old stuff and added drop brackets(after trying it without them),"WOW" what a difference!They perform "almost" identical.Trackbar/Steering is also something that needs to be addressed at these heights.

The RE 4.5" kit with the aal is the same price as the Rusty kit with the full rear spring. The RE kit has upper and lower arms, and the Rusty kit only has lower arms. Is this something I should be cautious of?

My plans were to buy the RE kit with aal, and save the difference in cash from the full spring kit for now. The money could come in handy elsewhere, and later, when and if needed, do the rear spring upgrade.

Initially I'm gonna run a 4.5" kit with 33" rubber and see how everything goes, and if necessary, do the necessary upgrades and strength adds to run 35" rubber.

The RE Superflex( or Currie) arms are the key to maximum flex in an XJ!If you just wheel sometimes and are not getting it tweaked to the max then get the Superride arms!

Just a note. I have superride lowers and needed tew udjust them after putting on my drop brackets and barely got one to move. The other is siezed. Tube began to crush after hot wrench and 6foot pipe wrench.

If yew get the adjustables, disassemble and never seize the sh1t out of them before yew install.