I didn't notice much difference in mileage. I got 12-13 city before and after. I got 17-18 highway before and same after. Doing 75+ over long distance I was stuck around 16 before and again same after. I have 25/65/18 BF Goodrich All Terrains (same diameter and width as the 285/75/16's).What are you guys getting for mileage with the bigger tires? Do you notice much performance difference?