This was my first weekend with a GPS. Day 1 was a wash because I didn't set the wheel size to automatic and wrongly set the size to 700.

Day 2 went well and I gathered some nice baseline data. But after loading it to Garmin Connect, RWGPS, and Strava I see different values for a lot of the means--HR, calories, elevation. . . Why would that happen? Don't these sites all take the data from the GPS unit?

(Uploading to 3 sites isn't my plan to go forward, I'm just trying them out to see which I like best.)