Sorry, it has been a long day. I meant is this a CASTER issue......

I have about 4.75" of actual suspension lift on my Unlimited JK and still have the factory LCA's. I have been chasing a wobbling steering wheel for the last two weeks since I put 37" tires on the rig. I have had the tires re-checked for balance, and they check out ok. When traveling at 40 MPH the steering wheel wobbles slowly back and forth but only if I let go of the wheel. If I put two hands on the wheel, it doesn't wobble, but the Jeep seems to wander around the lane. This characteristic only happens between 35-40 MPH, and stops at freeway speed or below 35 MPH. It appears to be bump steer, and I am starting to suspect the LCA's need to be changed to adjustable ones. I measured my Caster yesterday and it is reading 2 degrees measured at the bottom of the C's like shown on this site. Do you think this issue will correct itself when I install the new adjustable arms? It is just strange that it only demonstrates this issue between 35-40 MPH, however it wanders pretty good at that speed.

Thoughts? Should I adjust to 5 degrees for 37's?

 

Lower control arms will allow you to adjust the caster back into the 4-6 degree range, which is what I believe you want for that much lift, but could be wrong. Someone else may be able to give more insight into how much length you'll need.
2 degrees in too low, obviously.

Do you have an adj. Track bar as well?

 

Yes, I have an adjustable track bar. Axle is perfectly centered. At 2 degrees my front coil springs have a noticable bow to them. Im hoping this takes care of the wobble and wander. Just strange that it only happens at 40 MPH

 

Setting caster above 4deg should fix the flightyness.

For the bunpsteer, are you running a flip or a trackbar relo bracket with dropped pitman arm? Your steering angles may be off, or too steep, which could cause it.

 

After you get the LCA's, and adjust the caster to what you think is correct, go to an alignment shop and see what it actually is.

 

I have a lot less lift than you and the caster degree you mention means a lot. The lower degree the more flighty my jeep is. I have played with my own caster with my adjustable lower control arms and I like the bigger numbers, but I doubt my driveshaft does. So find the area that works the best for you.

I don't know why it wobbles your steering wheel at only one speed area for your driving.