Originally Posted by knightmare1015

Basicly it take more power to turn those larger tires than what your truck has available. The end result is a slower moving vehicle with poor mpg rating. Now there are a few things you can do to increase the horsepower and torque, but it still wouldn't be enough. Basicly you'd be better off doing an engine and trans swap to compensate for those larger tires, or the easiest is to stay away from the larger tire if you want better mpgs than what you'd get with the larger tires.