So I finally get me a pair of 8.5" Contours for the front of my M3, and my 225/45's are shaking something fierce.

Story goes like this...I had 225/45 Potenza RE 050's mounted on my stocker 7.5" wheels up front, then sourced a pair of 8.5's with 245/40's. I mounted these knowing it would be temporary as a buddy of mine staked claim to the 245's (came off of a totaled M3). Upon taking the 225's and putting them on the 8.5's (nicley stretched :D ), I started getting a horrible vibration in the steering wheel.

Now, this vibration was never noticeable with either the original 225/7.5" set-up or the 245/8.5" set-up, but is unbearable. I've just ordered a set of Dunlop FM 901's, sized 245/40/17 (so I can rotate), hoping this will cure the problem. Hasanyone else run into a problem like this before?

Could it be that maybe the wheels are bent?

or the wheels may not be properly balanced.

Nah, one of the wheels was recently refinished and the other, I was told, was straight (by my tire guy). Plus, they balanced them when they put them on.

I'm hoping my new 245's will solve the problem.