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Inconsistency in detecting cadence and speed

I recently installed the GSC-10. In just some basic testing, I noticed the red indicator was working consistently with the pedal stroke, but the green indicator would work for a bit with the spinning wheel but then cut out completely. I would hit the reset button and see the same behavior repeated (worked for a bit then cut out). I tried various things with moving the magnet and arm but in an indoor test (me simply holding the bike up and getting the wheel spinning) it was inconsistent. I paired successfully with my Forerunner 410 so I decided to take it for a spin to see if it was happy while I was riding. It appeared to be.

Now I am seeing some inconsistency in how it is performing. I had one or two rides where speed and cadence were sensed fine. Another ride where only speed worked (maybe it was using GPS for that?). The pairing appears fine. On my ride on the trainer this morning, nothing worked (I hit the reset button but it didn't make matters better). I was on a Kurt Kinetic trainer for this morning ride and I did read something about trainer magnets screwing things up so I'm not sure if that was the issue.

I feel like it is installed correctly since I have had some rides where it was solid. My first thought is to change the battery.

Any guidance would be greatly appreciated.

Thanks
-joe

0 tigermountrider over 9 years ago

The light flashes about 50 times after the button is pressed then it stops.

Magnetic trainers are a problem for the newer sensors that don't use a wheel magnet but not the GSC10. When indoors WiFI interference can be a problem.

The magnet should be centered on the line on the speed arm with the gap between the arm and magnet being 2 to 5 mm.

0 JOEROSS7 over 9 years ago

Thanks for the reply, TIGERMOUNTRIDER.

I'm embarrassed to say the loss of signal was related to the sensor sliding a bit on the chain stay from being pulled in and out of my car (no bike rack yet). I had a solid ride (from a tracking perspective) on my trainer since correcting the alignment so you are right about the trainer not being an issue.

Thanks for the information on the flashing. I thought it might be something like that but didn't see it documented anywhere.

-joe

0 IbisMojoHD3 over 9 years ago

Hey.
I don't want to start a new topic for this, as my problem is also cadence related.
After struggling with pairing my Edge 810 with GSC10 and finally got it working, I went for an easy "test ride", came back home and seen that my max cadence was 179 rpm!!! There is no way on Earth I could pull this number.
I understand that there is no way (and need) calibrating it, as the cadence sensor's job is pretty simple.

What should I do to make it work properly?

Thanks for any advice.

0 tigermountrider over 9 years ago

One possibility is you had the cranks level with the magnet parked next to the sensor when going downhill resulting in some spurious triggers. Another is the magnet is too close to the sensor. That can cause double triggering.

0 IbisMojoHD3 over 9 years ago

Hey. Thank you for quick reply.
First option is out, because my relaxed position is with the left crank forward.
I've checked the magnet and it's about 4mm away from the sensor.

I will see if it's still an issue after a few more rides. This was the first time after pairing the sensor and maybe I shouldn't panic this much.

0 tigermountrider over 9 years ago

The recommended distance is 2 to 5 mm so that shouldn't be it either unless you're using a stronger magnet.

0 IbisMojoHD3 over 9 years ago

Today's new "record": 238 rpm (avg 67 rpm). I'm using the original magnet that was included in the set.
Is there any way of calibrating it or something??

0 tigermountrider over 9 years ago

It just counts triggers so there is nothing to calibrate. It may be the sensor acting up. Try resetting it by shorting the battery terminals together for 10 seconds or so. Putting the battery in backwards with do that.

0 petitbogho over 9 years ago

Speed and wheel sizing

I have been having hard time using the cadence sensor GSC-10 in connection with my Garmin 920;
If I let the device getting automatically the wheel size my speed barely pass 12 k/h.... usually it's in the 30/40 range.

How can I solve that?

Thanks

0 chunkywizard over 9 years ago

That might be down to mis alignment. Check the GSC10 is still aligned with the wheel magnet and it is close enough to the wheel and not shifted away slightly

HTH

CW