the AT's will always have a longer tread life. However - I had a set of 35" Goodyear MT/R's on my 93' chevy that I wheeled the piss out of off road and managed to squeeze 44,000 miles out of them before selling the truck. They still had quite a bit of tread left. If you're building a mall crawler just get a set of AT's - you won't have to rotate them near as much and the tread will last much longer.