Slight Steering Wheel Shimmy- Suggestions?

[eurekatrading]

I sometimes (but not always) notice the steering wheel shake ever so slightly at lower speeds (apprx 40 MPH). I have also driven my car at 100 MPH and there was no shimmy in my steering wheel. The car also tracs straight at all speeds. The BMW dealer said that there is a slight bend to the right front and rear rims, although I can't see it. Is it crazy for me to spend $1,200 (rims, balancing, alignment) if I can only occasionally notice this? I just replaced all 4 tires and had them balanced as well. Any suggestions?

[Grease Monkey]

I think you need to get to the bottom of this problem. The first thing I would check is the runout of the front brake rotors. If they are warped (and this is not uncommon on Z8s) you could pick up a slight shimmy in the steering wheel which should feel worse under braking. Even if it doesn't feel worse under braking, I would still have them checked since a warped rotor can transmit vibration while the car is cruising. If this checks out, I would have the best tire shop in the area, preferably one using Hunter equipment, recheck the balance of your wheels/tires to make sure they were done correctly. If they have a problem getting them to balance, i.e., if they have to use an excessive amount of weights, suggest they use the match mounting technique to try to cure the imbalance. At the same time, have them check to see if the wheels are "true" or if they have been bent. If they are bent, there are wheel rebuilders who may be able to fix them for you but often the costs involved approach the cost of replacing the wheel entirely, especially in the case of the Z8 wheels since they really aren't that expensive when compared to others. You could also check with some of the guys who broker "take-offs" and see if you can pick up some replacement wheels at a good price. E-bay is the place to start. If you still can't find the problem, you should have the suspension checked to see if there are any ball joint issues, check the steering rack for play, and check the condition of the wheel bearings. Of course, you could also just live with the slight vibration you described but since you seem inclined to stretch her legs on occasion, I think it would be wise to figure out what is causing the shimmy.

[eurekatrading]

Thanks for the extensive comments and for spending so much time. You, and others like you make this board great. Thanks again... Jeff

[FWK-Z3]

If you don't drive your Z8 very much, this could be caused by rust developing on the brake rotor around the perimeter of the brake pad. The will cause a slight ridge on the rotor that drags every time it passes betwen the pads.

The cure is pleasant - drive your Z8 more.