ok guys I have a question for you here, a bubby and I have been having a discussion about tire size and mpg, not tire width but height. The question is if a vehicle had say 15 inch wheels and you changed to 16's which would get better mileage?

 

33 inch tire on a 15 inch rim is exactly the same height as a 33 inch tire on a 16 inch rim,
same on a 17 inch rim, and believe it or not, the same height on a 20 inch rim.

Answer would therefore be no, no mileage increae or decrease.

Well, maybe a little, very small miniscule.

33 inch tire on the 15 inch rim would have more sidewall than on the 16 inch rim, so a little extra weight,
but the 16 inch rim would weigh a little more than the 15 inch rim, so it would probably cancel each other out.

Only benefit of changing rim size is looks, and tire availability.



phox

 

http://www.dakota-truck.net/TIRECALC/tirecalc.html
http://www.off-road.com/tools/gearcalc.html

here are a couple of calculators that give diffrences in tire sizes and how they affect rear end gearing. nothing that tells you the mpg change though, I would think there would be too many variables such as current differential ratio, engine output (hp and tourque)