on my 328 coupe i have got standard m sport wheels, with 7.5j x 17 on the front, and 8.5j x 17 on the back, what size tyres should i have on the front and what on the back? i had 235 40 17 on both and the asc light came on occasionally, (and stayed on) but now i've got 235 40 17 on the back, and 225 45 17 on the front. the light comes on all the time above 50 mph! they have got 16mm difference in diameter and i think this is why my traction control keeps coming on and staying on. HELP! i
ts driving me crazy!!