Originally Posted by
nomadmax
Recently, I've ridden with folks who have GPS based cycle computers and in comparing the data I'm always 2 or 3 tenths higher in mileage. I intend to change the input number and believe if the number for 700x25 is 2105 and 2096 for 700x23 then I should bump the number to 2110 or so to get it closer to accurate.
I use a Cateye and I compare its recorded distance to the distance I get on Ride with GPS, and at first they did not match—the Cateye was higher. So I began to decrease the circumference number in the Cateye by 5mm at a time until they were close, but still they never match. Finally I decided there was a little bit of deviance in both.
RwGPS shows a distance in tenths, whereas the Cateye gives it in hundredths. But if I switch to the RwGPS
Edit Ride page, and
Show Metrics, it gives a number in ten-thousandths, e.g. XX.xxxx. I find it hard to believe that is accurate; a ten-thousandth of a mile is 5 feet.