I have the Edge 500 + GSC-10 settings for a wheel size of 2096, which is roughly my roll-out calculation (2 revolutions divided by 2) and a "normal" setting for 700cc wheels plus 23 tires.

I have done about 140 miles over 4 rides with the 500 (parallel with my Edge 305). I notice there is a difference between the 500 reported distance and the gps calculated difference which is enough to throw off many stats for the rides. In attempting to manually estimate a correct wheel size I use the following formula <correct wheel size> = <gps distance> * 2096 / <Edge 500 distance>. Applying this to my 4 ride sample gives a consistent <correct wheel size> ~= 2086.

I will adjust my Edge 500 wheel size setting to 2086 and see what happens. But while the error is under 1%, it is noticeable. Interesting that the Edge 305 device distances for the ride are near the gps calculated distances from Edge 500 data. The Edge 500 reports accuracy of 12 ft in the open under clear sky and declining to 18+ ft under trees in overcast.

What are others finding / using for wheel circumference?

I have done about 140 miles over 4 rides with the 500 (parallel with my Edge 305). I notice there is a difference between the 500 reported distance and the gps calculated difference which is enough to throw off many stats for the rides. In attempting to manually estimate a correct wheel size I use the following formula <correct wheel size> = <gps distance> * 2096 / <Edge 500 distance>. Applying this to my 4 ride sample gives a consistent <correct wheel size> ~= 2086.

Code:

Edge 500 GPS <gps>*2096/<Edge500> 46.41 46.17 2085 41.17 40.98 2086 22.32 22.23 2088 30.36 30.20 2085 *Distances in miles

What are others finding / using for wheel circumference?

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