Originally Posted by MAR
Anone know why BMW puts 215/40/18 front and 245/35/18 rear on the 135 when everyone seems to think 225/255 is better? There must be a reason BMW uses that as the OEM setup.
I think BMW puts such a small front tire on for 2 reasons:
2) To help dial in the amount of understeer the engineers wanted, while making it possible to be reduced by the enthusiast.
However, a 225/245 setup would be better for reduced understeer. i have no proof of BMW's motivation, but this is what I surmise.