Another reason for differences is the fact that the odometers are not very accurate. I've measured mine on the interstate by going 10 miles and seeing how much it is off. If it is one tenth off, your odometer is 10% off. I decided on the highway today that mine is reading about 10-15% less miles than I'm traveling. So ALL my mileage and distance till reserve needed to increased. Now I'm up there with most of you guys. I plan to get a more accurate error check with a GPS.
The other interesting fact is that my spedo reads FASTER than I'm actually going. Measured with a GPS, at 78 mph, I'm actually going 73 mph. This is the reverse error of the odometer.
