I wanted to step up to a larger tire size... 285/75x 16 's seem limited, and only avaliable in D rating. 235/85-16, are only 31.8" in outer diameter, but there are a lot more choices avaliable out there, but are avaliable in E ratings. However, I dont tow all that much ( I do however haul some heavy stuff in the bed from time to time, 150 or so cinder blocks). Would I be ok with a C or D rating? For some unknown reason to me, why are 16.5" tires cheaper than 16" tires across the line? There are obviously less tires avaliable, but what is avaliable, is about 30-40 bucks cheaper than the equal size in 16".