I put a bit taller tire on my VX last week. On the trip home yesterday I had reset the GPS Odometer and my Tripmeter to zero. At the end of my 100+ miles I had 135 miles on my GPS odometer and the Trip meter shows 130. My MPH is right at 2 mph different. I show 70 on the speedometer and 72 on the GPS. Is there a math wiz that can help me with a calculation to verify me fuel mileage occasionally? My Ultra Gauge is currently showing 18 mpg it has been steadily climbing since I have gotten back to Iowa and am doing more than just city driving. In Florida I was happy to get 15mpg both with the gauge and calculation of Miles and gallons per tank.

THanks.

Rod