Before installing a 3.25" I took a measurement of my stock caster with an angle finder on the steering knuckles.

I found that my driver side had 3.5* and the passenger side had 6*. So, as part of the lift I also installed adjustable lower control arms in hops to work out the caster difference which I assumed to be causing my slight driver side pull.

I adjusted the control arms to the point where the caster was 6* at both knuckles, but this caused one control arm to be substantially longer than the other. This condition would lead me to believe that the wheel base is shorter on one side of the Jeep than the other. So, I decided to adjust both arms to roughly 22 7/8".

This leads me to a few questions:

1. Shouldn't the stock caster be the same at both knuckles?

2. Should the control arms be exactly the same length?

3. Does the control arms adjust the wheel base length?

 

In order for the control arms to adjust castor on each side independently, they would have to be twisting the axle housing. I don't think that is possible, and if it is, I would think not advisable.

Maybe you are not getting a good reading?

 

Maybe I'm not getting a good reading... Although, I also tried the same measurement on the shock mount and got different numbers from each side, with stock control arms.

 

The Caster should be symmetric.

In order to change the wheelbase you would have to change the upper CA in the same direction as the lowers.

When you just adjust uppers or lowers the axle rotates around its own longitudinal axis.

Even then you are limited by the trackbars. If you adjust the length of the links it can lead to binding.

 

The castor from the factory is different from side to side to compensate for the crown in most roads in the U.S. It isn't your imagination.

 

My castor was 5 degrees on both sides at stock ride height

 

Spinlock,
"If you adjust the length of the links it can lead to binding." What links are you referring to?

is it safe to have lower control arms of different lengths to accommodate for the asymmetrical caster?

 

That little tidbit of information is contradicted by the castor specifications in the FSM:

Caster: +4.2° ±0.5°; max left/right difference: 0.65°
Camber: -0.25° ±0.37°; max left/right difference : ± 0.5°

No mention of one being different to compensate for "road crown".

 

That may be true. But in practical application, I don't believe that anyone in stock form has the same caster from side to side.

 

Are you sure the surface (floor) that the JK was measured on was perfectly level? I have heard of slight differences between the right and left knuckle surfaces because of the welds but they should be pretty close. I would set the lowers at 23" eye to eye on both arms and see how it handles. And yes, longer control arms will lengthen the wheelbase.