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Tires vary a lot in rolling resistance new, and even more so as the tread wears down, so between best and worst tires there might be as much plus or minus 2 MPG from the factory tires.




Tires can vary a LOT. On my 96GT Mustang i've had a few different tires over the years. When i first got it i had these old BFG Comp T/A's... probably one ov the first Z-rated to really attack the aftermarket. Threw them on and holy [Edited by Moparts - Family Friendly Site - Keep it clean]... they were LOUD. Remarkably loud. After a few months i found some newer tires, swapped 'em and noticed immediately how quiet the car was, and also how much further the thing would coast once off the gas in neutral. Rolling resistance has always been in the back ov my mind, but this clearly illustrated how huge this can be. That was switching to some other super HP Z-rated summer tire too. There are 'high mpg' tires out there that i'm sure would be the same difference between my best tires and them. They'd handle like garbage, but i bet that car'd roll forever.