I believe largest tires on 8in wheels up front. No rubbing or problems yet. Did have 245's up front. SS/SC stock height Getting 30,000 Plus on front and trading back to front before the wear out thus getting another 30.000 miles total 60,000 miles on set of tires.
Drive freeway 90 percent of the time 3500 miles per month.

 

I was thinking about 255/40 18 by 8 wheels and tires for my Cobalt Turbo. Do they ride good with no rubbing? Do you have any pics to share? thanks

 

Pics?

 

I wouldn't do It 235 is ideal size for a 8 inch wheel any bigger and its just pointless even john Powell said so bigger isn't always bigger...

 

255/35/18 would be almost identical to 225/40/18's in height. I may be getting 18x9 or 9.5 wheels with 255/35's in the near future.