This is one of those, "dunno. How much tire can you manage to get under there?" kind of deals. Mini-tubs are not standardized. I'm running 28" 325s M&H Racemaster drag radials on the street with a whole lotta room to spare. I'm running a 28x10.5W (wide) slick, still with room to spare. I think I could still get 2" wider under there, but I didn't know that before I tried, and also, I think it will be really tough or impossible to find a stiff wall tire in the perfect size.