iamjero

I just purchased a pair of Currie adjustable front lower control arms and I am having trouble finding info related to installation on a 2010 JK and the length to set them to to get my camber back close to stock with a 2.5" lift.

resharp001

y, most of the time you're not going to get a suggested measurement when purchasing arms separately. You might look at instructions for a 2.5" kit that comes with only the lower arms as those instructions should have a measurement, or you could probably just start with 1/4" or 3/8" longer than the factory lowers and go from there. You're likely to have to tweak em once anyhow to get them perfectly dialed in. Also, you said "camber", but you really mean "caster".

SoK66

Most 2.5" lifts don't call for extending the lowers, and last time I looked at Currie's 4" kit instructions they left all eight arms at stock length. Not sure how tat could possibly work properly. Stock lowers are 22 5/8" long. A common rule of thumb is to set them at 23" - 23 1/4" with a 3 - 4" lift. With a 2.5" kit I'd start at 23 and see where your caster comes out.

iamjero

Caster is the fore or aft slope of the steering axis. The steering axis is a line drawn through the upper and lower ball joints of the knuckle. Positive caster is when the bottom of the steering axis line is in front of the tire's contact patch. Zero caster is when the steering axis is at 0 degrees. Factory alignment specs for basically all vehicles call for a certain degree of positive (shown) caster. This ensures good stability, helps maintain straight-ahead direction and promotes steering wheel self-centering.

You are right. Thank you for that. I was thinking the correct concept, but calling it the incorrect name.

resharp001

Y, it happens..... I knew you knew what you were talking about in general which is why you were adding adjustable lowers to help correct the issue.

Rednroll

23in from eye-to-eye seems to be a common magic number for many as a starting point. I would start there and then have an alignment check after to see where you're at and then adjust if you're picky. On a lifted JK, you're typically aiming for 5 to 5.5deg of caster.

I have the Mopar 2in lift which is about 3in of actual lift. I'm sure most 2.5in lifts will be around 3in of actual as well. Stock length LCAs are 22 5/8in". I originally did some calculations using the Pythagorean theorem based on the actual 3inches of lift amount and it came out to 22 13/16th in length.


When I had the alignment check at 22 13/16in length, my caster was at 2.7deg which is on the low side but I really wasn't experiencing any problems. I just knew, I could likely increase the ride comfort if the caster was higher.

So I adjusted my arm length to 23 1/16in to increase the caster. My caster is now at 5.3deg which is right in the sweet spot I was aiming for.


There was definitely some trial and error on my part and it took me multiple adjustment attempts and then bringing it into the shop for sanity checks. Others have used some pinion angle measurements to get a general ballpark of where you're at after adjusting the arms but I haven't been able to quite figure that out.

iamjero

Thanks for the suggestions. I will try to find an example of a fixed length control arm for a 2.5 inch lift. If that proves to be unsuccessful I will go the trial and error route.

Rednroll

Really the more difficult and important part of installing adjustable LCAs is in figuring a way to tighten down those jam nuts while also keeping the mounting ends aligned. Some have created some nice elaborate jigs. Some jam pieces of steal between the mounting brackets and the arm ends with the arms on the rig.

This is the method I came up with which uses a bench vise, and a C Clamp (ie pretty common tools). Then I tightened that jam nut with a pipe wrench with a 2ft pipe over it, the pipe was from one of my floor jacks.

Here's my LCA jam nut tightening setup. Use red loc-tite on the threads.

iamjero

This is exactly what I was looking for. Thank you all again!