I believe that this only might matter to TOD in the front. I have been running a 32" on one side and a 31" on the other rear since Oct. No problems. As for running it on the front, I will have manual hubs and the front will be free wheeling except on trails anyway. I think there may be a lot of unjustified crazy no different size tire hype. I couldn't find anywhere that anyone put theory to practice.