shv2.7T

I have a 2000 2.7T, 92K miles, fabulous ride.
Hae had issue of vibration at highway speeds (60-80 MPH), felt both at steering wheel and thru seatover the last year.
Had 2 tires replaced due to vibration/worn tread with Goodyear Eagle F1 GSD3; then had a blowout in one of the 2 remaining older tires, replaced these 2 with Dunlop SP Sport 9000( had an original unused spare, and bought one more).

Have had tires balanced multiple times due to vibration, no luck. Recently had road force balancing( Hunter) done, the mechanic said that the road force balance was not 'off' by much( < 20 lbs), but that the 'regular' balacing had not been done right- after this there was no vibration for 1 week, but I feel it returning gradually. Any suggestions; is there a reason for the wheel/tires to go off balance again? Apparently the wheels are not bent/damaged.

Thanks in advance.

paulroad

you are running differnet tires front and rear?

All the tires have different amounts of tread?

Have you checked how much of a difference?

shv2.7T

They are all relatively new tires, i.e. treads are similar; albeit different sets on the front and rear axles.

audikillsbmw

It doesn't take much to cause issues with the Quattro system.

bman33

Despite the tires having the same sidewall rating (i.e 235/45/17), tires brands have different circumferences, spring ratings, etc.

If the Road Force balance solved the issue for a week only, I'm gonna guess that the tire is spinning on the wheel enough to essentially go back out of balance. Do you stomp on the gas alot? Make sure the Road Force shop uses as little tire mounting soap as necessary to get the tire mounted!

paulroad

different diameter tires will upset the system and vibration can result.

Not to mention you have different traction ability for different tires this too is not adviseable.

A regualar rear wheel drive or front wheel drive is fine with mismatched f/r tires. But you wouldn't do a sid to side missmatch, would you?