245/75R16 fits on the 2WDs with factory 16" wheels. Fitment will depend on your wheel offset. I needed to put a tie wrap around part of the front mudflap to keep it from catching when reversing at full lock sometimes.
if you trim the mudflap a little, 235/85R16 will fit. Anything more than 31.5" means you need to trim/flatten the body seams in the front arches, and remove front mudflaps.