Originally Posted by
msu2001la
I have a Garmin Edge 520 and use the ANT speed sensor on the rear wheel, and a cadence sensor on the crank arm.
It works fine for measuring/displaying speed and distance while riding on indoor rollers and stationary trainer.
I think that's the only purpose of the wheel sensor, right? It works outside too if I forget to turn the GPS back on, but I assume when I have GPS on, the head unit is using that to measure speed/distance and not the rear wheel. Hmm...
I don't know exactly how the Garmin units work. I emailed Lezyne and they said it tracks distance with the sensor if it's connected, but if it loses connection it will revert to GPS. So I still had to mess around with the wheel diameter numbers to get it accurate.
As an additional point of info, when I sync rides to Strava, Strava uses the actual distance and speed info from the GPS data, and does not use the speed/distance from the sensor. Which is nice on those rides when the sensors fail or get interference from someone else's sensors, at least I still have accurate data.