Some of the fuel efficient tread designs offer "up to" a 3% fuel savings, and those are usually marketed heavily and cost extra. I ran across this article which proposes you can save 30% or more based on variables. Fuel economy is one consideration when buying tires, but a smooth running coach lends itself to better fuel economy, so in the end it's a win win. For what it's worth-
http://cumminsengines.com/uploads/do...el_economy.pdf