jgwilliams

I'm wondering if anyone else has had issue with combined speed/cadence sensors on Garmin GPS units? When I bought an Edge 520 Plus I kept my Garmin GSC-10 that came with the old Edge 705, and for a long while it worked fine. Then one day it appeared that the speed sensor side failed; that wouldn't have been a problem except that rather than using the GPS for speed my 520+ decided I was doing 0 mph. I had a spare GSC-10, so I popped that on, but some time later the same seemed to happen to that. So then I bought a Topeak Duoband unit, which worked fine. I then upgraded the Garmin to a 530, and it has continued to work fine until just recently, when the same thing happened.

I find this a bit more than coincidental. I've taken the Duoband off and tested it, and I can confirm that the speed sensor itself is working as it operates a diagnostic LED for the first x number of pulses, so I have to conclude that it's something to do with the Garmin software. The Duoband has both ANT+ and BT, so I thought I'd switch the Garmin connection to BT to see if that does the trick. I do have a magnet-free cadence sensor, but the area I cycle in has a lot of tree cover, so the speed displayed can be a bit erratic if I rely purely on GPS.