if you have over sized tires on it, put the stock size tires on it, this will increase the torque reaching the ground, and put less of a strain on your drive train, increasing fuel mileage at the same time.
if you have over sized tires on it, put the stock size tires on it, this will increase the torque reaching the ground, and put less of a strain on your drive train, increasing fuel mileage at the same time.