Garmin 010-12843-00 Speed Sensor 2, Bike Sensor to Monitor Speed, Black

I use this on a 29" mountain bike rear tire for indoor winter training on a bike trainer.Pro, Con, and Resolution.Pros: Reports a consistent speed that I believe feels appropriate to my road riding. There is no weird highs/lows. Paired quickly with Garmin 645 and Garmin Connect.Cons: You can find all over the web that if you spin the hub it does not wake up and I can agree as I wanted to throw it against the basement wall and was ready to return it. I had to keep removing the device, then remove the battery and put it back in, and then reattach the device.Resolution: What I found out...I was so very frustrated when it would turn on when I moved the bike on the floor (two rotations) and it would NEVER turn on when it was on the trainer. When I would disengage the tension on the wheel it would work when it spun free.What I realize and highly believe is with knobby tires on a mountain bike it generate lots of vibration in the wheel that must mess with what I assume is the accelerometer. I think it is looking for a specific curve and it gets lost in the vibration.Still is not a good thing to disable and then reenable the tension to get it to work but at least I know and do not need to mess with the battery.Wish: If Garmin would be listening...a press to turn on would be great to avoid this whole issue of not waking up. Or just sense vibration not rotation because there should be a way to firmware update that.

I had the old version of the speed sensor for my Edge 500. It had to read the magnet on the spoke. This newer version just clamps onto the hub. Easy peasey! Pairing was easy. Just had to go into the bike settings and turn on the speed sensor setting. Spinning the wheel wakes up the sensor and then it paired. I guess it calibrates itself as there is no options to enter for wheel size. As a handcyclist I run 650c wheels.

Easy to set up and install. Anybody who has any gripes about using this thing is too picky. It went on the hub in 5 seconds, paired it through ANT+ to my Garmin smartwatch, set my wheel diameter and right away it was available in a tracked activity to show my speed and generate charts at the end of the workout. Works flawlessly.

I have to say the device itself and it's easy installation are great. Where it has been left down is the glitchy companion app. I took two or three times to get it setup do to the app stalling or continually stuck in a loop. That being said once it was said up it is very straight forward and I really like it. I think the ride time maybe slightly off but I'm sure in future updates it will be resolved.

Found out that it was not compatible with my Garmin watch, but it can connect directly to Garmin Connect app. My bike was on a trainer stand and I recommend peddling when trying to pair the device. It just ensures that it doesn't go to sleep in the middle of pairing. My LED doesn't seem to work, but I don't care if I get the data. It also does not seem to sync on demand. I got an empty cycling activity, then a half hour later my cell phone chimed and my data showed up. It is currently also reporting the wrong time zone. Apparently you can change that through the Garmin website which doesn't allow anyone to log on (just watched a circle spin round and round on chrome, Firefox, explorer and edge). I don't know why time zone isn't set in the Garmin Connect app because that would make way more sense. I had to enter my tire circumference three times before it finally stayed set. At the end of the day if I get accurate distance, all other shortcomings can be forgiven.