max Duster tire size

I've got M/T 29.5/11.5 slicks on mine with some room to spare, however, my springs are moved into the frame rail, it's mini tubbed, the quarters have been rolled and pushed out and the opening has been massaged both fore and aft. You are somewhat limited on overall diameter with out major surgery, especially with slicks that grow. About 30" in diameter is all you can go. Otherwise I have had a 15/33 in there on my 10", 7.5" backspace rim and it only touched lightly so there is room as far as width goes. The tire was only about 1/4" from the front wheel opening at the rocker panel though so it had no room to grow. I'm going to go ahead and narrow the rear about 3 inches per side and use a 12 inch rim with some 29.5/13's on it though soon. I figure by narrowing the rear the exact amount needed to perfectly center the wheel in there I'll be able to fit a little more.