Indoor trainer - Garmin EDGE 810 + Strava = BS
Running into a bit of an issue and there isn't a reasonable explanation for it.
Equipment used:
Minoura FG540 Hybrid Roller
Garmin EDGE 810 with GPS turned OFF
Garmin Speed Sensor on rear hub
Apple iPhone 6S 11.0.1
Garmin Connect App
Strava App
Fairly new to using an indoor trainer but have figured out enough to get everything working. Garmin 810 has the GPS OFF for an indoor ride. It was manually turned OFF by me before the ride started. Garmin Speed Sensor is registering and distance and speed are both registering.
Proceed to do a 40 minute interval training ride. The wheel is turning on the roller, and the sensor is registering the speed and distance for the entire ride. It was a good ride, and my average speed was 18.46 mph on the Garmin. The distance was 12.4 miles. Using the Garmin Connect app, the ride was uploaded from my Garmin to Strava. Everything is fine, until I look at Strava. Upon inspection, Strava has me at 12.3 miles, and an average of 17.3 mph. This is disappointing to say the least.
Why is there such a difference in the average speed, and sometimes the max speed? I had posted before regarding a friend using the app on a phone vs me using the Garmin and uploading to Strava. It was decided that differences would be there due to how the GPS data is recorded and processed by the phone, the Garmin app possibly, and Strava. OK, that part is fully understandable. What is not understandable is why a ride with the GPS OFF is showing differently on Strava than what was recorded on the Garmin. If the GPS is OFF, why isn't it transferred over as is, and if it is being manipulated, why?
This year I am keeping a running total of all of my rides, trainer, fun, commutes, every single mile is being recorded. At this point, Strava has not proven itself accurate enough for me to keep my records. Because the GPS is what I am using on the road/trainer, that is what I am going with. After searching a bit online, I see that people have created documents to keep in the cloud that will track everything from miles to HR and cadence, etc. Strava is fine for the social part, maybe those who are not nit picky about how their miles transfer over, etc. The stats part of it has been fun so far, and seeing such a big discrepancy is a huge turn off.