I put on brand new 19s with falken tires and now at speeds above 100 km/h my car is vibrating, not so much the steering wheel but the whole car.
Is it a balance issue?
More than likely. I can't remember how fast the balancers these days rotate the tires but I seem to recall it's around 55-65 MPH. Things change when the wheel spins faster than the balancing machine. You might also have a settling period which could throw things out of balance. Could be a bad tire with a broken radial that under pressure is causing the problem or a rim that wasn't true from the factory.
I would look at the wheel weights on each wheel to see if there is one wheel with excessive weights. In my opinion there should only be a couple weights on each wheel, maybe one towards the inside lip and one towards the outside. If you notice one with 5 or more weights my guess is they had to over correct a bad tire or a bad rim and there is only so much you can do for that. If they are new enough you might be able to request a new wheel or tire as a result. If you find one in question you might be able to pull that tire off and see if the wheel has a high spot or if the tire itself is bad.
When I had my new 19's balanced first thing I looked at were the weights to see if any were excessive. To my delight I had no more than two weights on any of the 4 wheels and for me that means true on the tires and wheels before they were mounted.
Do you have the correct centerbore on the wheels? I was "centerbore ignorant" when I had the wheels on my B6 Passat, and it rode like $hit. They also gave me the wrong lugs. Anyway, hopefully just a re-balance.
Last edited by blaah; 06-14-2012 at 12:32 AM.