I do a lot of 300 mile trips pulling my Coleman Key West Pop Up Camper. Pulling the hills of the Pa. turnpike I was always in the 9 to 10 MPG range. I recently decided to make some changes to my truck and lowered it to 4" of lift and took my 35" BFG AT tires off and for now have the stock wheels and tires on. Last week I went on the first trip of the year with this set up and was absolutly amazed!!!!! I got 13.9 going out, and 13.4 coming back back home. I had no idea I was taking that big a hit on gas mileage by running the big tires. I have decided that no matter how much I like the look, I am not going back with todays gas prices!