Can I use speed/cadence sensor as cadence only? On my mountain bike the wheel is quite far from the sensor, therefore I expect some drop outs. I would like not install the speed magnet at all, and just use it for cadence and GPS for speed & distance. Is this possible?
No. Their are separate ANT+ profiles for speed, cadence, and speed/cadence, and speed/cadence cannot be used for cadence alone. When the separate Garmin magnetless speed and cadence sensors came out I got them for my mountain bike and have been using them since. I couldn't use a GSC-10 because of the geometry of my MTB.
I misread the question as asking whether you could use it as a cadence only sensor along with a speed sensor. But you're right, just don't use the speed magnet and the head unit will use GPS for speed and distance. If you start out with the magnet on and the speed sensor working and then it falls off or something it takes several minutes to make the switch to GPS, but not if it's not there to begin with.
If you have the GSC10 you can move the arm closer to the wheel by undoing the screw at the end. There's usually more than enough movement to adjust for most wheels. Better yet if you really want speed from a sensor, grab hold of one go the magnet-less sensors that you wrap around the wheel hub.
thanks it is indeed working as described. Without speed magnet it uses cadence only. On my mtb I have a cheap decathlon mtb sensor, that cannot be regulated as easy as gsc-10.
