Can Gary confirm my assumptions?

[daranco]

OK... for a 2009 335i vert w/ sports package:

(1)Since a winter set-up can go -1 down to a 17" rim (like 225/45ZR 17), I assume that I could also use 225/45ZR17 for a summer or All season package as well..... I also assume that using 225/45ZR17 would give me a bit better comfort ride (over using 225/40ZR18)... AND also having same size on all 4 wheels would allow front-to-back rotations to extend tread life??? Correct

(2) Other than extreme / limit cornering, what would I be loosing if I got rid of the
rear 255/35R18s in order to have same size all around ??

My priority is to get best ride, quiet, and best tread life.... and willing to give up some
extreme performance (since I don't race or track)... and I'm used to a big car ride.
Am I correct in going with 17s vice 18s, and also going to same size all around ??

Thanks for your patience and guidance

[Gary@Tirerack]

1. Yes, in fact this is very common to do and would give a softer ride than the OE 18" setup while allowing you to rotate the tires.

2. Cosmetic appearance isn't quite as aggressive compared to the staggered 18" setup, but thats mostly a matter of personal cosmetic taste.

Given what you're trying to accomplish, minus sizing to 17" with 225/45R17 would be the way to go.