What I meant was, if you have 16" inch wheels you can put on a bigger size and hence you will lose MPG. Sorry that was unclear, and its not always the case I know.

 

Camdisco, you are definitely usually clearBut still unclear on this one. You can put bigger size tires on any size wheels. Its the overall diameter that affects mileage, not wheel size. So no mather if you have 22 inch wheels with low profile 33 inch tires, or 15 inch wheels with thick 33x12.50-15, in the end they are both 33 inch tires and will yield the same mileage loss due to a 33 inch diameter tire. no mather the size of the wheel.