Custom C.A's opinions please

I am building homemade U&L control arms for my MJ. I'm going with about 5” of lift up front (4.5" RE XJ springs + extra stock rubber bushing) I have looked up the length form the control arm/lift chart that states for 5" lift the uppers should be 16 5/8 and the lowers should be 15 ¼. How many have used this chart and how accurate is it? I don’t want to screw up the lengths if I am doing it once. I will be using 1 3/4 .120 wall tube for the lowers and 1 1/4 .120 wall tube for the uppers, I'll be making up the ends and using 3/4 threaded rod to go into the threaded inserts.

everyone's seems to be a little different, so go ahead and start with those lengths, but be sure to make either the upper or lowers adjustable. get some large 1.25" or 1.5" threaded rod and nuts to do that. the only other option really would be to setup the axle under your XJ with the caster set properly and at ride height and measure then make them to that length. but even then if you want to add or take away an inch, you have no way to adjust...

When I was at 5" with RE fixed lowers(16"),my uppers were set at 15-1/2".

Thanks for the replies guys. They will both be adjustable. The 3/4 rod kind of needs to be used due to already available materials, budget and taps being available for free. I see PoisonSpyder recommending 3/4-16 for suspension links, there will be at least 1 3/4 rod threaded inside (maybe more) at all times depending on adjustment.

This rig won't really be wheeled to much, more of a lifted DD. Got the YJ for bashing. I can see why you'd recommend 1.25" rod tho, makes sense for those hard hits on rocks.

you guys think 3/4" rod too small for casual wheel/ D.D?

Ok, as someone that has actually built his own control arms many times here's what I've got for ya.

#1 - .120 wall is hardly enough for a rollcage, why would you make control arms out of it? NO WAY. Get some good DOM in at least 1.5" x .250 wall. Why skimp on control arms? They break/bend on the trail.....you're f*cked.

#2 - 3/4 heims. NO WAY, the rock buggy guys can get away with that, their rigs weigh about 1/3 of what you're loaded XJ will weigh. When you're building a trail rig, that you want to survive & not leave on the side of the trail for 'dead', you've gotta think BIG. I would use no smaller than a 1" heim, and I recommend JJs. Currie now sells a JJ with a 1" x 14pt grade 8 bolt welded to it. 2.5" thread & a hellofa lot of weld area on the JJ. These work very well.

#3 - Length. This is really the easiest part of designing your own arms. Each XJ out there is running a different tire size, trimming amount, etc etc. So why buy the same arms everyone else is for your CUSTOM project? The way to determine your arm length is this: support your rig on stands, remove all stock arms/coils/TB & etc., position the front axle so that the LCA mounts are inline with the frame end mounts (or drop brackets), bolt a tire onto the axle & position the axle front to back (and rotate for caster) so that the tire will clear the front bumper & turn lock to lock. Measure your distances & build your arms. This is the furthest point that the axle can move forward, thus this is the perfect arm length if you can turn lock to lock without hitting anything. Build the arms with at least .5" each way adjustability & go wheel it.

Remember to set your caster throughout the setup of your axle or you'll be rebuilding your upper arms later!

Good luck, and dont forget that you're not building a go cart, you're building a trail rig that's suppose to be SAFE, STURDY, and get you home after the run. Overkill is usually just enough.