Originally Posted by c1apton
It's not actually bigger wheels- it's shorter tires. Lower profile tires (shorter circumference) will rotate faster per 1 revolution causing the speedo to read higher and adding additional mileage.
shorter tires = faster speedo readings/ faster odometer mileage
taller tires = slower speedo readings/ slower odometer
Yeah, that is what I was thinking. However, lower profile tires do not necessarily have a smaller outer circumference than higher profile tires.