I believe zoeydad meant zero angle with respect to the drive shaft.
With a 3.5" lift, he wants the pinion to be in line with the drive shaft, and the ends to have stock caster.

 

I was too vague in my request. What I need is the desired caster angle and the desired pinion angle. If you have tilted up your pinion to eliminate vibration, what is actual pinion angle?

Unfortunately, advertised lift height isn't always relevant. One mfg's 3.5" lift is another guy's 5". Actual pinion tilt measurement is crucial.

 

The stock pinion to caster relationship is difficult to work with.
Anything that would end up with the pinion pointed up higher, and the caster near stock, would help a lot. Adjustable arms can do the fine tuning.

As for a number, all you can do is average out what most people have for a lift.
There are lots of posts with pictures showing some pretty large pinion angles in an attempt to have a good caster angle. Maybe you can look at what people have to settle with and get an angle that would put most people in the ball park.
Almost anything in that direction would be good.

 

I'd like to see a PR44 set up for:

• 3-3.5" of lift
• 4.5 degree caster (factory spec)
• zero degree pinion angle (that is to say, pinion and front drive line aligned with one another)

Note: I've been running less than factory spec castor for well over a year. I'm not willing to accept the drive line vibes and potential long term effect they can bring about. My JK steers more quickly than one with 6-7 degrees caster, yet it's anything but darty, tracks perfectly straight, and my pinon angle is very healthy.

 

What I need is-
With my pinion pointed at the t-case, the pinion is at ??* angle with a ???" lift (assuming a stock, non clocked t-case) .

As an example, my custom Jeep has a front pinion angle of 12* with a clocked (flat) Atlas and a 4" lift. My YJ has a front pinion angle of 7* with a D300 t-case and 4" of lift.

We measured our own Jk nad have the measurement from it but we'd liek to see a range of applications in hopes of finding a happy medium.

I really appreciate your time and help on this project.

 

So that we're all measuring apples. How do we measure pinion angle?

 

I guess you would simply place a magnetic degree finder on the front drive train (this contingent on your very best visual estimate that the pinion of the front diff is in alignment/same plane as the front drive train). No?

Or maybe if you could rest the degree finder on the yolk?

 

Indeed RC, factory caster is 4.5 degrees (see post #14 just above yours), but 2.5 - 4" lift is going to capture a lot more JKs than an axle set up for 4 - 6" lift, FWIW.

 

mine is 6+ degrees caster on 35 with 4lift kits.
by the way i blow my transfer case because of wrong angel, dealer fix it, but i [aid for the whole things

 

Caster angle between the vertical plane ( perpendicular to the ground ) that pass throug the center of the axle shaft and the plane that pass through the center of axle C holes.

watching the car with the front to the left and the back to the right, you can see that this angle is inclined clockwise ( so positive angle, if counterclockwise is negative ) of some degrees.

Basically, a positive caster angle creates some forces that bring the steering back to the center, and helps to have more stability on the steering.
As you can understand, wider is this angle, more stable is the steering ( but heavier also ), if this angle is narrow, your steering wheel will be lighter and you'll feel the car more handy .

The stock JK caster angle is around 4,5 degrees ( so quite narrow ), infact has some flightly steering issues. Normally, on a offroad vehicle the caster is around 6 degrees, but on normal road cars can arrive to 10.

Of course, if we lift the vehicle, the caster angle changes ( and becomes narrower ) a bit, that's because adjustable control arms are suggested in everycase.

i hope to heve been clear with my maccheroni-english