Quote Originally Posted by Reasoned1 View Post
I have 18" x 8.5" ARC-8's (ET38) with 245/40 PSS' on my 2004 330i ZHP, and they fit good and ride fine--nicely balanced and slightly less tramlining than stock. I'm not lowered (although I could) and wanted a slightly beefier sidewall to protect my wheels, fill out the wheel wells, and correct my speedo. I stuck with 8.5 to play it safe and, because I think that's optimal enough for performance--not to mention they were on sale for 25% off.
THIS. It seams like 245 is the ideal tire width when going square on 8.5s. Im going to through 235s on there. I know I'm encouraging oversteer by going square and with a narrower tire than stock but its not like it'll be uncontrollable, right?