I’ve been noticing intermittent spikes in my cadence… pedaling along at 85-100 and next thing I know I’m at 160-170 (shown)… I know better… changed the battery in the sensor, reacquired the sensor, did everything I could think of… any suggestions to facilitate a fix?
http://sheldonbrown.com/cyclecomputer-magnet.html
no possibility of this?
huh… intresting… I do have bladed spokes. My milage seems correct … but that may be self correcting from the gps… I’ll try changing the spoke magnent out, or removing it and see if it clears up… thanks
I also found that with my Garmin unit the magnet on the spokes was occasionally being picked up by the cadence sensor on the far side of the chainstay unit. This happened on one particular bike where the clearances were pretty tight and the spoke magnet was especially close to the Garmin unit. I initially diagnosed the problem by taking the magnet off the spokes altogether to see if the cadence spikes went away (they did).
I permanently solved the problem by moving the spoke magnet farther away from the unit (about 1/4 - 1/2 inch) to make it slightly mis-aligned. That put it in position where it was still close enough to be picked up by the speed sensor, but too far away to be picked up by the cadence sensor on the other side.
It’s strange, but it worked.
Are you using a powertap? If so maybe the cadence sensor dead and it’s relying on the powertap’s estimated cadence, which is pretty awful and often behaves as you described…
no powertap… spun the magnet on the spoke, so the plastic was to the sensor, and not the screw on magnet and the problem has gone away. Thanks
problems back…and it’s not just spikes, it’s pretty much doubleing my cadence… I know for a fact I’m not spinning 160at 14mph, or 210 at 24mph… and it’s doing it on both my 705’s
took the spoke mag off, new battery in the cadence sensor, ended up swapping the sensor from my g-friends bike and I still have the problem… it will read correct for a few revs, then double up… WTF?
You wouldn’t happen to be riding with your girlfriend when this problem occurs, would you? Maybe your 705 is picking up both sensors? Just a thought…
Are you using a powertap? If so maybe the cadence sensor dead and it’s relying on the powertap’s estimated cadence, which is pretty awful and often behaves as you described…
I’m having a similar issue as the OP, but I have an Edge 500 and Powertap Pro. There’s random spikes in my cadence that go as high as 240rpms and I’m fairly certain I can’t spin that fast. Before I got the GSC10 sensor, I noticed a lot more frequent crazy cadence spikes when the Edge would pickup insanely high rpms estimated by the Powertap. After mounting the GSC10, the spikes are much less frequent, but why am I getting them at all? It seems the Powertap estimates are somehow bleeding into the readings by the GSC10.
Is there any way to disable the cadence estimates the Powertap sends?