Quote:
Originally Posted by adeuel
I'm putting 265/40-19 Alpins up front on the OE 19" staggered setup.
285 rears are readily available, and my dealer parts counter said there is a bulletin recommending 265 up front instead of the non-existent 275s.
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I'd prefer a less wide front for the winter, but I'm concerned over the disparity in the tire diameter difference compared to stock. I'm probably splitting hairs, but stock is 27.7" front, 28.0" rear. For my summer tires I have 26.8" front and 27.2" rear. A Tire Rack specification gives rotations per mile and stock sizes are 751 front, 743 rear. My summer is 777 front and 764 rear, giving a difference of 13 rpm versus 8 rpm stock. The 265/40 and 285/40 are listed at 760 rpm and 743 rpm, a 17 rpm difference. Does that cause more wear on the transfer case? Is it worth worrying about? ......I don't know.
I'm sure it might take many thousands of miles for the wear to become a problem, but if I can avoid it with the proper tire selection and not have to replace the transfer case at over $4K for parts alone, I'll do it. I bought the car with the stock 705M 19" wheels, knowing I'd use them for winter, and have aftermarket 20" wheels for summer.
Did you happen to read the bulletin he referred to? Is it from BMW? Is there a source where I might find it, I'd like to read it.
Edit: Just read the BMW Winter tire flipbook and they show the stock 19" wheels with a 265/40 front and a 285/40 rear, so I assume there's no problem with doing that! That might be the bulletin your parts man was referring to.