Sponsored by The Tire Rack

[kmac1980]

I was just thinking, that when I switched over to my winters a few weeks ago, and stood the winter rears next to the summer rears, there is quite a substantial difference (1"+) in rolling diameter (wish I had taken pics)

I'm using BMW recommended winter sizes (235/40/18 all around)

Anyone have any idea why BMW went with such a disparity in tire sizes in the rear?

[Radiation Joe]

Originally Posted by kmac1980

I was just thinking, that when I switched over to my winters a few weeks ago, and stood the winter rears next to the summer rears, there is quite a substantial difference (1"+) in rolling diameter (wish I had taken pics)

I'm using BMW recommended winter sizes (235/40/18 all around)

Anyone have any idea why BMW went with such a disparity in tire sizes in the rear?

That choice surprised me. Even though they are pretty skinny, I would have thought BMW would have recommended the 225/45-18s over the 235/40-18s. Then the rolling diameters would have been at least close. Maybe they want to fool us into driving slower in winter?