I have been curious about this for a long time, I was wondering if the over-sized tires being put on the utilities throw off the milage any? I would think bigger tires would = to less milage?

 

yes, a larger tire will roll further (per revolution) than a smaller tire

you may be able to re calibrate the speedo,,,,like the trailtechs. Not sure about the factory speedos though.

 

what are the two tire sizes?

you can just do the math to figure out your difference in speed

 

How exactly does the machine measure the milage?

 

the trailtech (aftermarket) computer uses the actual diameter of the front tire and then a magnet attached to the rotor records the speed of the revolutions.

Im not sure about the factory Ute speedos,,,they may come off the tranny.

 

A lot of speedo's are geared off the trans. Quick non formula way of checking, use a quality gps

 

I don't think the stock speedos are very accurate. My Foreman is about 3 mph too high. So larger tires might bring it down to where it should be. Just so the tires aren't too big. - My speedo has added about 300 extra miles that I've never ridden. (Approx.)