So I was thinking about this the other day that I drive ALOT of highway miles and only a few city, maybe 80/20. Right now I have the stock 265s on there and I was thinking about 315s. Wouldn't my mileage actually benefit from the bigger tires because my engine would run at less RPMs on the highway. Now, I know I'd take a hit in the city, but if i was easy on the pedal and just got it moving slowly then it would work to my advantage. Anyone have any experience or thoughts??