I am looking at buying a F-350 Dually. It is a 1999 super duty diesel 7.3 L turbo charged, and a dually with 39.5" tires. I was wondering if there is a big difference in fuel millage on a dually than just a regular like F-250 or F-350 diesel?
Thanks

 

Mine is a gas burner & it gets 15 & 19, Thats about what the newer diesels get.

 

any time i have ran trucks with big tires like that gas or diesel mileage goes down. if the gears in the diffs have been changed to match the bigger tires mileage should not go down .

 

I would have to agree with naiper.[hr]Bigger tires can give you bad gas mileage.