Dr. Peter M Grosser

I have a 2000 A4 Sport with 205/55/16 Dunlop 8000E's on the factory 10 spoke alloys.

Ever since the car was new, I have experienced a vibration at 118-120 kph = 73-74 mph. The sensation is felt mostly through the seat rather than the steering wheel, and feels akin to driving on a slightly rough road (at first I thought it was the sport suspension accentuating the poor road conditions in Ontario!). A balancing problem first came to mind, but I switched to snow tires (Bridgestone Blizzak LM-22's, same size on steel rims) and the vibration was still there, only slightly attenuated!! I lived with it, not having access to a dealer close by. I recently put the summer tires back on, rotating them front to back, and the vibration is back, just as before. The car tracks straight and true, and wear on all tires is even, so I am not inclined to think it is out of alignment. I am being forced to drive at 130+ kph (81+ mph) where the ride is smooth as silk , but I am pushing my luck with the local 62 mph law enforcement officers.

Any suggestions where I should start to solve this annoyance?

markbradford

Did you telephone a dealer and ask?

Dr. Peter M Grosser

Would a bad alignment cause a vibration only at such a narrow window of speed (118-120 kph)? I called a dealer and they suggested a balancing, but on some antiquated (surplused?) equipment - I presumed I would come out worse than I went in! My concern with the balancing is that the problem persists despite changing tires.

markbradford

on other rims, so Idunno.

Weird. Maybe a misshapen hub or something? I really dunno. Sorry

WClark

Another rotating mass may be a culprit. A brake rotor that wasnt balanced, a driveshaft that is slightly bent...