I think you folks need to get your Speedo error figured out. Some of you are saying horibly low MPG. well oversized tires is going to make your odometer run slow. Your probably getting a lot better then you think.
If you have a tach you can figure out you actual speed using these calculators and the nice gearing charts posted above.
http://www.ring-pinion.com/calculators/calculatorsind.htmlKnowing you gear ratio, current tire size, factory tire size the speedo was claibrated for and RPM's you can figure your speed and get a rough idea how off you are. I have done some playing with these and I thing they have figured in a little less tire hight to account for the fact most tires are not the size they say they are. If in doubt take off 1/2 an inch.
