Speed not working but cadence working

GSC 10???????? Might also help to know what device you are using with it. Also, if you use powertap or certain other power sensors, they will be a factor too. Below assumes you are using a GSC 10 and no other sensors.

There has been some posts that may indicate some devices just don't show speed when on a trainer with gps disabled. It was quite a long time ago since I read them and I may just be entirely wrong about that.

However, irregardless .... you need to check the alignment and ensure that when you do the led test that you get a green LED every time the wheel magnet passes the sensor arm and of course for the cadence a red LED every time the crank magnet passes the sensor. You should also try to ensure that the crank doesn't trigger the green or the wheel trigger the red, which I had happen before.

If it's the GSC 10 the speed sensor reed switch contacts can become magnetized and sometimes stick together, you can try giving the arm a few sharp taps to try and unstick the contacts, but if that doesn't work it's probably bin time.
I'm always careful to store my bikes with the wheel and crank magnets well away from the sensors to avoid any magnetism problems.

Hi. I'm experiencing the same problem. Got a trainer for Xmas and put a wheel magnet on. The g sc 10 has been reset and both red and green lights initially flash up but there after only the red indicator light flashes when the crank arm passes the sensor. The Green light doesn't flash when the wheel magnet passes the sensor arm. I believe everything is lined up correctly.
Any help would be greatly appreciated on solving this issue.

If you can't get the green to flash when the magnet passes, then the unit needs to go back to where you bought. Or, you need to get it closer to the sensor arm. Or you may need to upload a picture of your installation...... I've seen some bizarre setups of the gsc10 that can't possibly work for some local riders. Unfortunately I don't know them so it would not be prudent of me to ask what they were thinking.

I've had my sensor for over and year now without any issue. I just got a 920xt but it does not pick up the cadence sensor. It worked for the first few minutes of my ride but has ceased to work since. I've removed and repaired the sensor multiple times. I've made sure everything is aligned appropriately but it does not register. Even the speed sensor drops as I ride (both indoors as well as outside). I thought maybe it was time for a new battery, so I replaced it, but I continue to have the same problem.

Is this a known issue for the 920 or can anyone provide some insight on what may be happening?

Is this a known issue for the 920 or can anyone provide some insight on what may be happening?

I'd think it likely the gsc10, unless you have had it working with another device since trying it with 920xt. Did you do the test and get the red flash every time and a green flash every time? You can pair them with multiple devices at the same time if you have them.

With no red LED I'd tend to assume the crank sensor went bad. The red doesn't even flash when you initiate the test/reset procedure??

For some last ditch efforts.......take the battery out of your GSC10 and put the unit somewhere dry and slightly warm for a day or so to ensure it's dry inside, or maybe a hair dryer on low for a while. After that put the battery in backwards for a couple seconds or just use the edge of it to short the positive and negative contacts on the GSC10 together. Then put the battery back in and try the test again to see if you get the both red and green LEDs.