I've searched but found 100 different responses. I'm trying to make a decision between 17x8 and 18x8.5 wheels. I want to continue to run 245's in the back and 225s are fine for the front. Right now I'mon stock suspension but will probably be lowed soon. Is there anyway for me to run the 18's without having to roll the fenders?

bttt

You should be fine with the 245/35R18. It would depend on the offset of the wheel though. If I can help let me know.

Jim, I wanted to run Kumho MXs on my next set of wheels. The wheels would be 18x8.5s, and I planned to run 225/40 in front, 245/35 in the rear, except the Kumho MXs do not come in 245/35. Would I have any problem running 245/40 in the rear (rubbing, speedometer issues, etc)? Thanks!

245/40/18s are too tall for an E36. Like Jim said, you should use 245/35/18.

What wheels are you planning on running?...also find out what the offest is for those wheels. That will help in finding an answer to your question.

Oh and what suspension set-up are you thinking of running. Guys you get race springs or coil-overs ..and their car is real low usually have to at least roll their fenders.

You should be fine with the 245/35R18. It would depend on the offset of the wheel though. If I can help let me know.
Since I have 18" (2003 M3 rims)rims with 255/35zr18 I can say that even with a fender role you will still rub on big bumps/dips. I agree with jim that 245/35 should work with no rolling. I did run the 255 upfront until I had the fenders roled and there was no problem running the 255/35zr18 except it looked gay.. If you run a 255 in the back you are going to rub unless you add camber.