Originally Posted by himespau

I've occasionally noticed a (sometimes large) discrepancy between my garmin 800 and Strava (taking data from my Garmin). In just about every case, it comes down to the fact that the Garmin was taking revolution data while Strava was using Garmin's GPS data and my cadence/speed sensor battery was dying (or the sensor wasn't quite right with the battery anymore). Not necessarily the best way to tell that I needed to change the battery, but it worked to let me know.