It looks like BMW equips your vehicle with more than one possible size during production. Front 245/45-19, rear 275/40-19 and Front 245/35-21 and rear 285/30-21.
My suggestion is to contact the folks at TireRack......they are experts on tires.
You can either go on the website or call 1-888-981-3953 and ask for Walt at extension 372 and they should be able to help you out.
Thursday, November 12th, 2009 AT 9:05 PM