My 89 560SEL drifts to the right. Not a lot, but enough that I always feel that I'm compensating with the steering. It's been that way since I had it aligned in Feb 06. Recently I noticed increased wear on the outside of the front left tire. Again, not serious but noticable. I took it back to the same alignment shop (a place in bay areas that specializes in alignments). They said that the alignment hasn't changed since Feb 06 and that it is correct and the car shouldn't drift. They claimed it must be "a tire problem" and suggested I rotated the tire. The tires I have are directional so I wasn't able to do a true rotation, just front to back. No change after the rotation.

(left is the first column, right is the second column)
Caster 9.5 10.7
Camber -0.4 -0.4
Toe 1/16" 1/16"
Toe Total 1/8"
Rear Toe 1/32 1/16
SAI 11.8 11.9
Included Angle 11.5 11.3
Setback Front -0.3
Setback Rear 0.0
Track Width Diff 1.6"
Wheel Base Diff -0.3"

FYI, the left caster rod is at its minimum (shortest). The right rod has two turns to go.

They also did a Hunter GSP9700 balancing on all 4 tires and the report says the tires should have -2lb net pull (to the left). I've never seen this kind of analysis before so I'm not sure its significance.

Any experts on this forum that can interputt these numbers? I know about roads having a crown for water runoff but the tire wear seam to indicate that it is more than that. Also, other cars I've driven have tracked better. Thanks
~Dave