Control Arms in relation to actual lift...

So my search yielded a crap-ton of threads, and after sifting through them a while- I can't find a comparable question.

I run a 4.5" RE lift F/R with new full spring packs in the rear. I've got a few thousand (95% off road) miles on the lift. My front end is about an inch lower than what I'd like (1.25-1.5" rake), so I ordered some RE 5.5" coils to swap in. The 4.5" springs have a rate of 164 lbs/inch, while the 5.5" springs are 184 lbs/inch.

I run a Smittybilt XRC front bumper with 9,500 lb winch with synthetic line. he bumper is a heavy pig, but I like the clearance/approach and toughness so I'll deal with it I guess.

I'm fairly sure the new springs will give me the stance/clearance I want with the added weight carrying capacity for the bumper/winch.

My question is this- I run a fixed LCA/UCA set-up. I know going up in lift means approx. 1/8" in lower control arm length (negligible and likely have that much adjustment in the control arm pocket). However, it calls for an extra 0.25" longer upper arm.

Do I need a longer set of UCA's, since I'm not even really at a 4.5" lift due to the weight of my front accessories? (Not a fan of throwing in the coils and then realizing 'shit, this won't work.') UCA's are best changed when coils are out...


I know, I know- but a full set of adjustables and be done with it. That said- I'd rather not. If I must- who sells a full set at a reasonable price?

I'm going through a similar problem after I added more weight to the front. What you want to keep in mind is the spring rate rating doesn't just handle more weight. Think of it more like ride quality. Softer springs give a smoother ride. Spring rate is how many pounds it takes to compress the springs 1".

My front end is lower with the added weight but it still has a smooth ride. I cannot add any more spacers for my condition. Either ACOS or longer springs for me. If you decide to replace your RE 4.5" springs let me know as they are one of the springs I'm thinking of using. I built an excel calculator that allows me to plug in spring length and rate and it returns an estimated new ride height based on my front end weight.

Why not add spacers to to level out your ride height?

Adding length to upper/lower arms will recenter the axle in the wheel well and try to maintain caster.

At that height you should consider drop brackets or move on up to LA's!

longer upper control arms is going to push your castor in the wrong direction. readjust castor when you add the springs and roll with it. there should be plenty in the stock adjuster to do so.

here is the issue... you can buy longer arms and recenter the axle in the fender at ride height. but you are still on a relatively short arm and a steep angle. as the axle compresses the axle is also going to travel forward. so as you are now, the axle will find the center of the wheel well on compression. if you push the axle forward at ride height you can run into issues with coil bind, steering clearance, bump stops not striking properly on compression.

drop brackets will help you put the control arms on a more level plane, minimizing for/aft movement of the axle. i rand fixed RE arms on drop brackets for a while, it was much better. Long arms being the best solution.

At about 4 inches of lift you really should have longer upper and lower control arms, at least one set that is adjustable. You could get away keep the stock uppers.

If you only have X number of dollars to spend, at 4 or more inches of lift, buy control arm drop brackets. With drop brackets, you can use stock upper control arms, and it will be more comfortable to drive and more capable off-road.

Don't waste time or money with adjustable arms at this point. Long Arms or drop brackets! I ran mine for about a year with the arms mounted to the factory locations and it sucked! I have been running the RE drop brackets for about 8 years.

Greenz said:

I'm going through a similar problem after I added more weight to the front. What you want to keep in mind is the spring rate rating doesn't just handle more weight. Think of it more like ride quality. Softer springs give a smoother ride. Spring rate is how many pounds it takes to compress the springs 1".

Why not add spacers to to level out your ride height?

Click to expand...

I've ran spacers before and while they were OK (mainly DD and commuting duties back then), I would prefer not running them with the trails I run nowadays- as I do not run limiting straps.

VAhasnoWAVES said:

there should be plenty in the stock adjuster to do so.

Click to expand...

That's was my thoughts, although I truly have no idea how much adjustment there is.

Tim_MN said:

At about 4 inches of lift you really should have longer upper and lower control arms, at least one set that is adjustable. You could get away keep the stock uppers.

If you only have X number of dollars to spend, at 4 or more inches of lift, buy control arm drop brackets. With drop brackets, you can use stock upper control arms, and it will be more comfortable to drive and more capable off-road.

Click to expand...

The lowers are longer, fixed length RE arms for the 4.5" lift. The uppers don't change that much in length- so like you, I figure I can et away with them and be OK.


Looks like consensus is swap to LA or go drop brackets. LA make me change all my belly skids and my rock sliders. Not a huge issue, but time consuming nevertheless. My only concern with drop brackets is beating the piss out of them on the rocks and have them hang up on everything.

Of those who run the drop brackets- do you do many rock trails (Moab or Rubicon) and do they get beat to hell and hang up?

RE drop brackets and braces are 1/4" or 3/8" steel, you can pound on them all day. In Moab they are no problem, I have been there 3 or 4 times. On the Rubicon where you are climbing small to medium boulders often, they may get hung up once or twice, but you are more likely to get hung up on a differential.

For the improvement in road handling and ride smoothness, and the improvement in off-road capability, drop brackets are worth the minor compromise.

been running RE short arms on drop brackets for about five years. I can count on one hand how many times I hung up my brackets, several of those were backing out of a trail because a rig broke in front of us. I was quite surprised they didn't hang on everything, easily the lowest points on the front end (besides diff), but being so close to the tires, they rarely cause issues. Had stock uppers as well.

denverd1 said:

been running RE short arms on drop brackets for about five years. I can count on one hand how many times I hung up my brackets, several of those were backing out of a trail because a rig broke in front of us. I was quite surprised they didn't hang on everything, easily the lowest points on the front end (besides diff), but being so close to the tires, they rarely cause issues. Had stock uppers as well.

Click to expand...

This was the reply I was wanting to hear- one way or the other. They look like hanging up hunks of iron, but my stock ones aren't beat too terribly bad. You also mention RE short arms- did you just run the ones that were correct length for the lift? Or did you need to shorten them up due to the brackets?

Short Control Arms