[foolproof]

I just hung a 315/75-16 spare on mine. It measures 34-1/2" top to bottom. It does fit on the carrier, and just clears the third brake light. The wheel is 4.5" backspace vs. 6" for my stock Rubicon wheels. It will rub the bumper just a little bit, but the tailgate closes just fine. I wouldn't go any bigger than this on a stock carrier. In fact, if I could afford it right now, I would go directly to a bumper with a carrier built in, and take the new heavy spare off the tailgate once and for all.