[Hickster]

I managed 69.2mpg on the 170mile trip up to my folks on Saturday. That dropped a bit to 67.5 coming back - probably due to it being a good deal colder. I'm on the standard 15" R101 Rotor Spoke Alloys.

Quote: Originally Posted by kertjycoth (original)

It should not make any difference because the rolling circumference should be the same. Smaller wheels usually go with deeper tyres rather than the lower profiles of larger wheels.

After all if it made a difference then the speedo would be out as well. The key with wider section tyres associated with larger wheels is a slight increase in rolling resistance and a small increase in wind resistance.

Wheel and tyre size do make a significant difference not only to the economy, but to the speedo and the mileage. We've all seen this when we go on runs and find the quoted mileages are different to actuals. The circumference might only be slightly different but over hundreds of miles it adds up.