Will 215/35/18 fit 18x8 rims?

 

Yep, but for a rim that wide, I'd recommend a 225 width or greater.

 

will there be any performance probs or will it look stupid. I have a set of 215/35 from my old 18s but they r cracking(cheap adr). and i have a good deal on 2 18x7.5 and 2 18x8

 

they'll fit, but the sidewalls will be at like 45-degree angles...if you're worried about performance, get smaller wheels, 18s arent helping much. but yeah, ideally you'd have 225s or 235s for 8"-wide rim...

also, check to make sure your toyos will even fit on 8" wide rims...I've seen some 225s that could fit 7"-wide rims, and some that couldn't...they're all made differently, so look into that

 

yep... check with the tire manufacturer