Hey guys, I recently replaced by worn out factory Michelins with a set of Goodyear all-terrains. The Michelins were 245/75-16 and I averaged around 15 MPG. With the new 265/75-16 Goodyears I average around 13 MPG. I haven't changed anything else on the truck and I still drive the same routes everyday. Should the change in tire size affect me that much? Please help. Thanks.