Garmin Edge 500- spurious speed readings when cadence is zero.
Recently, I see strange behavior with my Garmin Edge 500 (+speed/cadence GSC-10 sensor). When I stop pedaling (i.e., down a steep hill) the speed sensor goes haywire, reading out unreasonably high (45 MPH) followed by unureasonably low (12 MPH) values (whereas I know I'm doing about, say 20 MPH).
By coincidence (or not), I updated the firmware just a few days ago (from 2.6 to 2.7). Has anybody else seen this behavior? Is it linked to the firmware or is it some other problem, do you think?
Do you get a reasonable speed displayed if you lift the rear wheel and spin the back wheel, or is it close to zero from using the GPS reading? Riders have reported odd speed problems that got fixed by putting a fresh battery in the GSC unit.