Originally Posted by dragoscscc

Recently took a trip around town, the bike computer registered 100.7 miles. Looked it up on google maps and the same trip was 98.8 miles. Right now I have the tire circumference set at 2173mm. To correct the error, the new tire circumference would have to be set at 2132mm. (100.7/98.8=1.019230, in order to get the same ratio with the tire circumference it would have to be 2132) However 41mm difference is huge, I could understand a 4 or 10 mm error but 41mm per revolution? I remember, to get the original tire circumference of 2173mm I actually measured the tire. I doubt I was off by that much (1.6"!)

So clearly my math must be wrong somewhere.

Or there's a 2% error between real world and google...

Interested to hear some ideas

Cheers
D