Polar S720i recording wrong distance
I just got the s720i Monday and went for a short 5km ride just to test it out. I wasn't wearing the heartrate monitor and was just testing the speed and distance. Everything worked and showed up in the Polar software just fine.
Last night I did a bit longer ride and went approximately 20km. When I got back home and stopped the watch the distance only showed 12.9 km. Everything else including the max and average HR, the time and even the altitude graph looks perfect. Only the distance was wrong.
Is there something I could have done wrong that the watch stopped recording the distance early but not the HR or time?
I plan to now do a couple rides at known distances to see if it's the watch or just a mistake I made. Just wondering if anyone else has had the same problem happen.