285/75/16 or 275/75/16 is what most people run on here. i have 295's and they fit but it is really tight and i still have some rubbing to take care of.
Most people cannot fit tires that size, but there have been some RARE cases where they can (HB 4x4 fit a 285/70/17, a very similar size, with literally zero room to spare). It really depends on the exact dimension of the tire you are picking and how aggressive it is (P vs. LT, AT vs. MT). Exact dimensions can vary a bit in the 285 category.