This weekend saw an aborted Asparagus and Strawberries. I used two devices, a 500 which I use just for recording and an eTrex 35 for navigation. As the ride was a 400K event I recharged the 500 twice causing the timer to stop (I really need a reliable OTG cable).
When I got home I uploaded the activities on to Garmin Connect and I have three rides, much as I was expecting. The first stage shows as 66 miles at an average speed of 15.5 mph in 4 hours 17. The second one shows as 70 miles at 13.8 mph in 5 hours 5. The third shows as 61 miles at 11.2 mph in 5 hours 29. I know the reason why the speeds are getting less, but that is not important here. When I stitch the files together I get 198 miles at 9.5 mph. How can I possibly get that? Average moving speed is 13.3 which is something like I would have expected.
If I do a quick calculation 198 miles divided by 20.75 hours does come to around 9.5. So 4:17 + 5:05 + 5:29 = 14:51 is my moving time which the other files have used to calculate the average speed. So how come this changes when I join the files together?
Strangely, the eTrex has also recorded the ride at, you guessed it, 9.5 mph.