So I finally got around to snagging some adjustable UCAs to go with my adjustable LCAs in the front. I'm been trying to chase down some minor bump steer or whatever you want to call it, and I liked where my LCAs at in terms of how the springs and shocks sat, so I wanted to grab the UCAs to nail down the caster. However, I found that there was always a 4* difference between my drivers side tire and my passenger, in terms of caster. If I twisted the axle so that the passenger was at 5*, the drivers would be at 1*. Is this normal? Might it be from the adjustable of my LCAs? (Both are currently set to the same length of 23" eye to, the passenger might be a touch longer though, maybe an 1/8"). Thoughts?

 

it's not uncommon for an axle to have c's that are not sitting at the same position. typically, i try to just work off of one side and stick to that side. having said that, you could always try taking a vertical reading off the pinion flange. if set correctly, you should get a reading of around 0°.

 

So the flange at zero will allow for proper caster? Is it easier to measure from the bottom or the top?

 

i personally like taking a reading from the top of the ball joint as it's quick and easy but, if you pull off your drive shaft from the pinion and place an angle finder flat across it top to bottom, that being at about zero should be right.

 

well pulling off the driveshaft sounds as fun as pulling teeth. When you say you do it from the top of the ball joint, what do you mean? I reference your writeup, where you have a picture of the angle finder on the 2 notches on the bottom of the C, so thats where I was measuring the caster from. Are you recommending measuring from a different spot?

 

yeah, put your angle finder on top of your ball joint and take a reading there.

 

These readings need to be done with the jeep on the ground or can you still do it while its jacked up?

 

has to be on the ground and take a reading of your floor. my garage floor has a slight pitch to it so i had to take that into account when i checked my axle

 

Cool, that's what I thought. I'll be replacing my front DS soon and then doing the same thing, getting my caster dialed in.

 

I don't mean to Hi-jack this thread but I feel this will probably fit right in. I've read numerous threads on caster and pinon angle I've also read the write-up on project JK regarding caster and I still need a little clarification. The higher the pinion angle the less caster correct? Therefore to obtain 6-8* caster the pinion would have to be parallel or actually pointing towards the ground correct? This being said I am in the process of installing a 3" long arm lift along with a JE Reel 1310 double cardin on my 2012 JKU Rubi. I'll be running 35's and its my understanding the additional caster over stock is to improve the handling with the lift and larger tires. The new drive shafts however, recommend the pinion be inline with the drive shaft thus having less caster than even the stock 4.2*. I know there has to be a compromise between good handling and drive shaft vibrations. My biggest fear is grenading my transfer case due to not enough pinion angle.. According to the Dynatrac caster write-up they mention even setting it back to the stock 4.2* could be enough to cause sever vibrations. Does anyone have any recommendations as to how much caster or what pinion angle to run with my setup? Thanks to the OP for letting me get that out and thanks for any help you guys may have. If you need more information please let me know.