What purpose does the rear wheel speed sensor serve for a garmin 500? Is it just for turbo trainer use? I’ve got a new bike coming and not sure I need to bother fitting the rear wheel magnet and removing the “arm’ from the sensor.

It does cadence too, I think, and it’ll sometimes be a teensy bit more accurate than GPS which can give you slightly off results occasionally, if you’re under tree cover or the weather is really bad. But you don’t need it if you just want to navigate/record your rides etc. I have an Edge 800 and don’t use the speed/cadence sensor.

I would still use the cadence function but I would just leave the magnet off the back wheel and remove the arm from the sensor as I think it’s just held on with a screw. 100% accurate current speed data doesn’t bother me.

What would you gain by not having it?

Oh right, I see. Not sure what would happen there, presumably it’d just take speed and distance from the GPS. Taking the arm off might compromise the waterproofing on the sensor though…

What would you gain by not having it?

Cleaner look.