lklimavicius

I saw a thread about the scarcity of 21" all-season tires. I am in the same boat. The 2013 S8 I just bought has dry-pavement tires and I live in Chicago. Needless to say, the car was like a cow on ice when the first snow hit. My question is this - I would like to by another set of rims and tires which I would use for winter and I noticed that there is a lot more selection in 20" and 19" used OEM rims and all-season/winter tires. Can anyone with certainty explain the do's and don'ts of messing with tire sizes? I hear that they key is to keep the sidewall height the same but there should be no issue with reducing the height of the wheel. I also heard that any change you make to the tire size has an affect on the accuracy of the speedometer, mileage, various effects on suspension etc. Just looking for some definite clarification / rules of thumb. Thank you!

andrewmr

It's not the sidewall height but the overall height.

If you go from a 21 inch wheel to a 20 inch wheel the sidewall will need to increase by a half an inch. Half an inch above the wheel and below the wheel makes up the inch difference.


Find an acceptable 20 inch wheel and put a 275/40 on it and you're good to go.

Stevereddy

Or a 255/45/19 will work. It is a base A8 wheel. I have Verde Parallax 19”x8.5” et 33. 190.00 each with Nokian R2 240.00 each from tiresbyweb.com. Superb snow tire, rugged wheel, great winter setup

MP4.2+6.0

Please search. I have posted what I think is really good info, but getting honestly tired of typing it over and over. It was in a tire thread again literally in the last three or four days that is just a few posts down. Read down the board post list a page or so for starters. Search on my prior posts about OE wheels, tires and such, as far as basic search terms. Google pointed at AW, not the deficient AW search box.

Stevereddy

What he said!!!!!+5

L0U

I use 265x40-20. For my winters on a 20x9 rim. Works great. Offset can be 20 to 40 range.