Does the tire wear look fine even on the front tires? I would check your toe alignment. Have you actually measured the caster angle before installing the shims or afterwards? If you take it in for a front end alignment, they will give you a print out of the caster alignment and you can find out if it is good. I need to check my toe alignment after a summer of heavy off road use.
...turns out that the alignment shop that did it 4mo ago did a crap job. My toe in was ridiculously off, i mean between the two wheels just stupid...I won't go back to the other shop ever. Also tires were out of balance. So looks like I'm fixed. No wobble no mo...
