[NCRob]

Am I best to just do a 275/35/20 square set up, or do the rears require a wider tire?

[pbonsalb]

Not required. I was in the same boat, with an extra set of 20s and was disappointed to find that the only stock size staggered snows would cost about $2k mounted and balanced. The Vredstein 275/20 are the only reasonably priced option in my opinion. Not ideal to mount them on different width wheels but also won’t cause harm given the low handling limits of snows that will cause you to go slower in the first place.

I decided to try something I have thought about but never done before — a third set of wheels with all seasons. I already had a set of 19” square 19x9.5s with 265 snows but did not like the handling. I’ll eventually put 275 snows on those wheels. But I hope to reduce the length of time I need to use them by running the all seasons. Michelin PS AS4 get fantastic reviews and there is even one video comparing them to snows and PS4s. In the spring I will know how my idea worked out. My wife has a Cayenne S with snows that I can use if a storm comes before I have time to swap from all seasons to snows.

[STi from DSM]

If I had a set of 255/45/20 from my X3M would those fit? These are 5x112, +35 offset. 255/45/R20 wheels. Thinking of buying an 18' M5 and everything seems to fit on paper.

[pbonsalb]

Way less traction compared to stock but should work. I was not happy with dry pavement traction with 265 snows. I know there is a compromise — I have run snow wheels on all my cars for 25 years, but this car surprised me. If you drive more slowly this won’t be a problem — other G30 cars are fine with 255s.