Originally Posted by
wphamilton
Not to imply anything about TC's data, but it reminds me that having suggested it I'm obligated to say something about methodology.
Make sure you're not selecting among the different rides. Use all of them that are applicable.
I did not hand pick the data. The only rides on this route that were thrown out were ones that had obviously different start or stop points, e.g. a ride where I didn't hit the start button until I was already 1/4 mile down the road.
It's good to select from a given time frame...
What difference could that possibly make? Are the roads different lengths on different days?
... and not from a given distance, type of ride etc. Same reason as above, and to eliminate variables.
How
about are you supposed to compare the repeatability of GPS-calculated distances if you use different routes?
If you have a "snap to road" option in your software, turn it off for the checks. Snap to road will basically report the map distance, not the bike's true distance.
No "snap to road" in my stuff.