What's the biggest tire size you can run on Hummer H2 rims without a lift kit? My Alcoa H2 rims have 3/4" less backspacing than my 16" stock alloys which means that they can handle a little fatter tire without rubbing. Can I fit 315/70R17s without a problem? The only other size I can find is 285/70R17 for any reasonable amount of money....

 

315s might rub on the outside, but they should fit. That setup was pretty hot a last year, so more than a few guys are running it-- I don't remember seeing many problems at all.

285s will definitely not rub, so if you feel like playing it safe, that's your best option, imo.