I trust Teraflex but I just want to double check before I begin installing control arms. I have a 2 door automatic about to be 3" to 3.5" with factory driveline for now. Teraflex says the caster should be 4.5 degrees. Is that what everyone else is measuring up to and agrees on?

My JK also likes to veer a little to the right. Teraflex has front lower control arms measuring 23-1/8 inches (driver) and 23-1/4 inches (passenger) in order for the caster to meet its 4.5 degrees specs. Is this also what everyone is measuring their front lower control arms to be in order to meet the caster requirements? Are these measurements pretty accurate to help with that veer to the right also?

I don't know how specific or vague my questions up top are. This is my first time dealing with adjustable control arms...

I suppose if my 2 door gets about 3" to 3.5" of lift and is running stock driveline, what should my caster be? How long should I adjust my front lower control arms in order to also help compensate that slight veer to the right? How long should I adjust my rear uppers until I sum up the money for an aftermarket rear driveshaft?

Thanks for the help.

 

FAQ's

And then:
http://project-jk.com/jeep-jk-write-...-end-alignment

Note that the Angle Finder measurement in the write-up does not equal the measurement from an alignment rack. It is simply a quick and easy adjustment you can do yourself.

(personally, I don't really like using someone elses ca lengths as a way to set my caster. Lots of variables involved between any two jeeps, even running the exact same lift. It will get you in the ballpark, but you need to adjust yours based on 'your' JK...)

 

EDIT: Answered my own questions I had just asked and now deleted.

But what about rear upper control arms? At what length should they be set on a 3" lift with stock driveshaft?

To eliminate the veer to the right, how much is the right control arm usually longer than the left (driver)?

 

You only have front lower adjustables? Not uppers? Putting one side longer than the other will have a very minimal effect, as it will simply twist the housing a little. To counteract the pull, you may need the uppers as well so you can move the entire axle forward on that side. (give it a shot and see if it helps...)

With an aftermarket rear shaft, you want the rear pinion pointed at the tcase. With the stock driveshaft, the angle isn't as critical. Pointing it up a bit will lessen the angles on that lower joint, but it is generally the upper joint (at the tcase end) that fails.

 

Hmm... see I'm low on cash so I can't go all 8 arms or even 6 arms. 2 sets of arms are all my wallet can deal with for now. After reading Planman's find on control arms and talking with Axsys, it seems I only need front lowers but may want rear uppers if I get rear driveshaft vibration.

Let me see if I have this correct... According to WOL's write up and Planman's, and what I think you are saying, front lower control arms will adjust the JK's caster. Correct? Stock is roughly 4.2 degrees. To decrease flightiness I want my caster at around 6 degrees or so of caster. Correct? Does that mean both lower control arms should be set at the same length? Will setting the caster at 6 degrees eliminate or at least reduce my slight veer to right? Or do I have to have the passenger control arm slightly longer than the driver in order to reduce that veer to the right? Even if my passenger control arm is slightly longer than the driver, that may not be safe without front uppers because of the awkwardness I'm putting the front axle in. Correct? What happens if both lower control arms are set to the same length?

Sorry for all the questions. I really do appreciate your help, and you are very helpful. I'm just trying to understand everything because I know very little about control arms. Luckily, my buddy who is refurbishing a YJ will be guiding me through the install. I just hope he's patient.

 

Easiest way to do this is set your front lowers to 23in eye to eye and see how it drives for you. If you feel ok with it, leave it. If it feels flighty still, go out another 1/8in on each side. 23in is a good starting point and most with the lift u have run that or a tad more with just the lowers.
Rear Uppers, you want to set these so your pinion is pointed directly at the t-case, maybe 1 degree lower in some cases.

Also, lengthening the lower arm on one side can help a little with the right hand pull, but with some tires ,your gonna get more of a pull than others. I suggest to set them equal at first, then go from there.

 

Thanks alot. You guys are such a great help. For nthinuf, here's a beer for putting up with me

 

There is a bit of a misconception here...

Open the write-up I linked, and read this one:
"Setting Your Caster "

The 6-8 deg caster that you are seeing is measured with an angle finder. (see the writeup). This is not a true caster measurement, it is simply a quick and easy way to get it done yourself. (angle finders measure straight lines, alignment racks measure some type of an arc. There is no direct comparison between the two numbers, but in the few posts I have seen that list both - the angle finder number is 1-2 degrees higher than the alignment rack)

So, you lift a few inches (with stock arms), and your caster goes lower. With a 3" lift, we'll say that your caster is now at 2.5deg. Using adjustable arms and an angle finder, you set it to 6deg. Now you take it down to the shop, and the rack has you at 4.5deg actual caster. Make a little more sense? (the reason I mention this is so that you don't run down to a shop and ask them to set the caster at 6-8 degrees...)

Now then, if your caster is too low, the handling will be flighty. If it is too high, you will have driveline vibrations. There is no such thing as a magic one-size-fits-all caster number that will work for everyone. All you can do is judge your driving characteristics, and make adjustments based on what you find...

 

nthinuf -- makes perfect sense. Thank you for everything.