My Garmin Edge 810 failed in the middle of my ride
At mile 49 of a 54 mile ride, I noticed that my Garmin edge 810 was no longer displaying my current speed! Additionally, I was no longer getting power data from my PowerTap. However, I was still getting distance data. I pulled over and recalibrated the power meter. However when I resumed my ride I was still not getting any speed data. Eventually I noticed that the distance counter at stopped, so I pulled over again. I noticed that I did not have a magnet on the rear wheel. The rear wheel is new and came with the powertap hub. I guess I forgot to install a magnet on the new wheel. Regardless, the Garmin edge should have been able to give me speed and distance from GPS data. Anyway, after I got home I tested the sensors with a Garmin edge 705 I had lying around - with the same results. It appears as though the batteries in both the speed/cadence and PowerTap are good. I'm considering factory resetting the Garmin 800. Before doing so I just thought I'd check the forum for other ideas.
Last edited by babyboomer; 03-24-14 at 12:58 PM.
Update - I disabled the power meter in the bike profile on my Garmin edge 810 as well as on the Garmin edge 705 and the speed and cadence readings came back. I'm not sure how to interpret that. I did replace the battery in the speed/cadence sensor (Garmin GSC). I'm going to enable the power meter in see what effect that has.
I considered withdrawing this post, but just in case it might be of benefit to others I will share my results.
I managed to avoid resetting the Garmin 810. Instead, I changed the batteries in both the Garmin GSC and the PowerTap G3. After replacing the battery in the G3, I tested both the 705 and 810 to ensure I was seeing speed and cadence data. Then I enabled the power meter channel on the both of those devices and rechecked them. I was getting speed, cadence and power data on both Garmin head units. I guess the bottom line is that, ultimately, I did not need to reset the 810 to fix whatever was wrong.
I had issues with a GSC-10 when I first got my garmin, and had similar issues to what you were describing (no power meter at the time). Even though it has GPS, it uses the wheel magnet to register whether you are moving or not, so if you lose your magnet (or have a bad GSC-10 in my case) you will get the squirrely results you got.
An easy mid-ride fix would be to tell your garmin you don't have a speed and cadence sensor, and it will get speed and distance from your GPS position fixes.
I suggest the official Garmin Users' Forums for answers to questions, addressing problems, and commiserating with other owners.
I know how to interpret. Lousy software.
Originally Posted by babyboomer