Does Tire Size Affect Gas Mileage?

[GasSavers_SD26]

I put taller tires on my bus for the simple fact that I needed new tires, and it was cheaper to go with taller tires rather than putting on new OEM tires and changing the rear end gear ratio.

While I like the rear end ratio, I do feel that the added height of the tire allows more air than I'd like under the bus, which doesn't help my FE.

[kamesama980]

going from 205/60 (what came on my truck) to 195/75 (stock size came in the bed of my truck because they're bald) AND calculating the numbers to account for it went from 21 mpg mixed to 24.5 mpg mixed. without calculating the change, there's no difference.