[rousslang]

I'm curious to know what the widest rim and tire combination is that is verified to fit the X3 M40i. My car came with run-flat mixed performance summer tires, though I was told by the dealer that I'd get all-seasons. Two weeks ago, we drove through a vicious snow storm in Southern Oregon, and since my car was near new (500 miles), I had just assumed the tires were as they said. NOT!!!! Car did not slip once in 4 hours, though dozens of cars and trucks were disabled on the side of the road, off the road, and smashed into the guard rail. I want to get a winter tire/wheel second set.

I have found this comparison online - first set is the wider, potential replacement, and the second is the OEM stock original set. Fit for the former is not verified. Any help is appreciated.


Diameter Tread width Rim
275/40R20 28.7" 10.8" 20 x 9-11"
315/35R20 28.7" 12.4" 20 x 10.5-12.5"




245/45R20 28.7" 9.6" 20 x 7.5-9"
275/40R20 28.7" 10.8" 20 x 9-11"