IrishJK09

Hey all,

I recently installed the Rough Country 2.5" coil and shock lift and after about 2-3 weeks of driving, my steering started to feel darty and loose. I rechecked all work, retorqued all bolts and nuts, and found nothing loose, bent, broken, or otherwise out of place. After checking around, I found out this is common due to a shift in the front caster angle, and the best work around is to recenter the axle with new track bars (or brackets) and adjustable control arms.

After talking with Dave at Northridge, I decided on getting the Currie upper front control arms to adjust my caster in order to save cost over the lowers. According to him, these are one of the few upper sets that adjust short enough to actually use to correct caster.

My parts have arrived and are currently sitting in the box because I actually have a bit of an issue... I have no idea what to set the lengths to. I know for 2.5" of lift, you want to set lowers to right around 23", however, I can't find much on the uppers.

So, my question.... With 2.5" of lift, what should I set the uppers to in order to bring my caster back closer to normal? Also, what is a good length for the adjustable front track bar in order to recenter my axle?

If these questions aren't actually something that can be answered without hands on knowledge of what I am working with, I understand completely and would be satisfied with at least knowing how to figure these things out on my own.

Thanks in advance all, I appreciate your time and knowledge!

greenamphibious

I would think that if anything you would want lower CAs to set caster. Although you can help caster with UCAs tha tis usually reserved for setting pinion angle.....

IrishJK09

This is true because uppers rarely adjust short enough to modify caster. I thought I needed lowers and was going to buy lowers until I spoke with Dave at Northridge and he informed me that I could save $100 by going with the Currie uppers due to the fact that they are one of the few sets that actually adjust short enough to help caster angle.

Now I just need some measurements to work with. The adjustable track bar actually came with some instructions that I may be able to decipher if I read them a few more times, but the upper arms had no instructions at all, so I am a bit lost.

IrishJK09

Bumping for exposure.

nthinuf

I didn't measure mine when I installed, I just set them about 1/4" shorter, tightened up and went for a drive. That should be a good starting place. If it doesn't feel quite right, just crank them in another rotation or two and remeasure the angle to make sure you aren't going too far. (from some of the write-ups installing both uppers and lowers, they are going 1/8" shorter and 1/8" longer, so...)

Browse through this if you haven't already:
http://project-jk.com/jeep-jk-write-...-end-alignment

'Stock' normal is 4.2 or thereabouts. But you'll want it somewhere in the 5.5 - 7 range now. Get a cheap angle finder like the one pictured in that link to help out.

This is in the write-up in the link also. Great info there...
Basically, you're just measuring from the outside of the tire to the edge of the fender (or frame rail, or whatever will give you the best measurement) on both sides. Then adjust the trackbar half the 'difference' between them to center the axle. Repeat if necessary...


One other note on those upper arms which you may or may not be aware of. You'll need to cut off a bolt on the stock uppers to remove them. (or remove part of the exhaust to get it out)

This is from the TeraFlex CA install guide in the write-ups section.
Probably a good idea to just browse through all the write-ups when you have some free time to kill. Check any of the lift or trackbar write-ups for pics and advice, even if they aren't 'specific' to your setup.
https://www.jk-forum.com/forums/jk-write-ups-39/write-up-index-quintessential-source-do-yourself-write-ups-42710/




-- Just noticed this thread - https://www.jk-forum.com/forums/modified-jk-tech-2/teraflex-3in-install-write-up-87577/
Skip over everything I wrote and browse it...

Calypso

Dave is right. The post above seems to have addressed your question about CA's. On the question about the JKS adj track bar, just follow the instructions, they are very easy. Once you re-center your axle, you'll be able to gauge what length your TB should be. You may have to make a couple of minor adj until you get it right.

IrishJK09

Awesome, thank you guys so much for the info.

mjcrna

so basically, you were only going with the uppers because they where cheaper and "Dave" said the JKS where adjustable enough to effect caster? I only ask because I'm about to address the same issue. I don't have the problem, i just want to avoid it, and want the ability to fine tune. I've got a TF 2.5" coil/shock, adj TBs, and would like to get the lower control arms. Doesn't teraflex call these flexarms? I was reading the teraflex instructions, http://www.quadratec.com/Assets/Installation/75302.pdf ,and are they basically saying stay with factory uppers on a 2 door.? It appears they are giving the measurments for the lowers, which I was planning to buy . .?

mjcrna

also looks like teraflex instructions are saying 4.5 of caster, but i've seen 5.5 to 6ish noted above, and elsewhere.

Northridge4x4

Uppers and Lowers do the same thing. If somebody is telling you differently they dont know what they are talking about.

Lower arms are a great choice and will work for you but they are a little more expensive.

David