Chips n' Shimmies

[Douglas Holcomb <d.p.holcomb@xxxxxxxxxxxxxxxx>]

>Thanks, but I've already done that. Twice. No help. Also there is no gross
>play in the various ball joints, bushings and wheel bearings I've looked
>at. The tires are new Pilots, but the problem predates the tire change.
>I've experienced shimmy due to wheel imbalance in the past, this just feels
>different.

You should probably look at the wheels themselves.  I've been fighting with a 
similar shimmy problem for months.  Diagnosis was complicated by having 
installed big brakes which limited options for switching wheels around and 
amplified the problem.  I concluded it must be the wheels - here is what I 
experienced.

1) Had the wheels (17") balanced several times. No improvement.
2) Checked suspension/bearings/steering for looseness and didn't detect any. 
Suspension has only 20k miles on it (M3 takeoff parts).  Ball joints are new. 
 Steering rack and tie rods and tie rod ends were replaced within 2 years.  So, 
doesn't seem likely its due to these.
3) Finally, removed big brakes and put stock ones back on - then tried original 
15" wheels.  No shimmy!  So, it seems wheel/tire related.
4) Replaced tires on 17" wheels (old ones pretty worn). Shimmy still there.

Conclusion - it must be the wheels themselves. Two different wheel balance 
places have noted that wheels are slightly bent.  There are no visible dents in 
rims, just slight out-of-roundness.  Neither place thought the bends were 
enough to cause shimmy, but I think I have ruled out just about everything 
else.

Does anyone else have thoughts?  Is it possible that something out of sorts in 
the suspension/bearings/steering could make the car particularly sensitive to 
wheel/tire variations?  I presume that low profile tires accentuate any wheel 
problems.

Doug Holcomb
'93 325i

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