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  • Lightweight hub design offers low drag; wireless technology makes it easy to switch speed sensor between bikes
  • Speed sensor attaches to the hub and self-calibrates with your Edge® bike computer, providing accurate speed and distance at all times including indoors on a trainer
  • Wireless crank arm sensor monitors cadence to maximize training efficiency
  • Compatible with Edge® and Forerunner® devices (sold separately)


View all Garmin Bike Computer Accessories

REI membership


Best Use Cycling
Batteries CR2025
Weight 23 grams
Rated 3 out of 5 by from Just installed and that wasn't easy I just installed the GSC sensor and it wasn't easy. Still haven't seen a light on the cadence and only twice with the speed. The largest band provided barely worked on my Ultegra crank arm. I was afraid of breaking it. The instruction didn't say which wheel to installed it on so I used the rear so I could use it on the trainer. Again I was afraid of breaking the casing. The real problem was pairing. Finally I figured out on my Edge 800 to use the “speed and cadence selection” thanks to a forum. This underscores Garmin very poor instruction resources. A few simple company youtube videos would eliminate my biggest complaint about Garmin's products.
Date published: 2017-03-25
Rated 5 out of 5 by from A Good Alternative to the GCS 10 I purchased this product for an older bike as I was wary of using the GCS 10 on it due to clearances being very tight to the wheel and crank arm. Using both of these sensors has resolved this issue. Like the other review, I did notice pairing was a bit difficult and once paired, the data was erratic for the speed sensor. After a quick check over everything, I replaced the battery in the unit and everything has worked superb since then. I suspect since movement wakes the sensors up, they have been on ever since they were produced since shipping and stocking them would bang them around in the box.
Date published: 2015-06-10
Rated 1 out of 5 by from Avoid, ANT+ compatibility problems I had hight hopes these new sensors replacing my old GSC 10. However I ended up disappointed. Somehow, Garmin has managed to create ANT+ product that has issues with at least some ANT+ head units. Including some Garmin itself makes. I attempted to use it with two different head units. Garmin Edge 500 and O_Synce navi2coach. Cadence sensor worked kind of OK with both of them. However it had noticeable delay of about 3+ seconds after I start pedaling and head unit starts displaying non-zero cadence. Delay with old GSC 10 combo speed/cadence sensor was not this noticeable. The speed sensor is where things more or less completely fell apart. When I attempted to use it with Edge 500, it kind of worked some of the time. Then Edge 500 would lose connectivity with it and wouldn't reconnect for a very long time. When attempting to use it with navi2coach, it would reliably connect and stay connected. However, speed readings were complete nonsense. It would show zero speed for 15-30 seconds after I started riding. Then it would show some speed reading which would update maybe every other 15-30 seconds. After coming to full stop, it would still show some speed (e.g. in 8-10 mph range) for a very long time before finally dropping to zero. Interestingly, Edge 500 would not display ANT+ ID of either sensor on the sensor info page. It would just show either dashes or zero for both sensors. Even after several pairing attempts. On the other hand, navi2coach paired with both without problems and happily displayed their ANT+ IDs. I'd stay away from these sensors. Get the "old" Garmin GSC 10. It worked flawlessly with every ANT+ head unit I had in past. Yes, it's a bit bigger, it has magnets, but at least it works reliably. I don't know what and how Garmin managed to mess up with these two new sensors, but they did manage to do it.
Date published: 2015-05-18
Rated 5 out of 5 by from Does what it says I ordered the combo on Tuesday; it shipped on Wednesday, and I received it in FL on Friday. On installation, nothing happened--the units would not pair. I replaced the batteries with new ones, which solved the problem. All I had to do was set the Edge 500 GPS near the sensors, and they paired immediately as soon as I started the search function on the GPS. Installation was easy with the included O ring type mounts--it took about 30 seconds each.
Date published: 2016-03-26
Rated 5 out of 5 by from Better than the Last LOVE the ease of installation and pairing with my Garmin 920xt and Garmin VivoActive! ABSOLUTELY seamless. FAR easier to take off to replace batteries. Hoping that the bands used to strap it onto the crank last (or will have replacements later)
Date published: 2016-01-15
Rated 5 out of 5 by from Works as expected I have the 920XT and it pairs up almost instantly. I'm extremely satisfied with this product.
Date published: 2015-11-02
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What is the third sensor pictured?  I recognize the speed and cadence sensors, what is the third item?

Asked by: eriqjo
The following are items included in the box: Speed sensor Speed sensor sleeve Cadence sensor 3 cadence sensor straps Manual
Answered by: REIservice
Date published: 2016-04-29

Since it's not compatible with the 610, is it also not compatible with the 410?

Asked by: cgcarey73
The Bike Speed and Cadence Sensor is not compatible with Forerunner 610 or 410 watches.
Answered by: REIservice
Date published: 2016-08-15

Will this work with the Edge 510

Asked by: rosshw
​Yes, this sensor will work on the Edge 510.
Answered by: REIservice
Date published: 2017-05-11

Will this work with the fenix 1 (original release)?

Asked by: Marktruckee
This sensor is not compatible with the original Garmin Fenix.
Answered by: REIservice
Date published: 2016-09-23

Will these Cadence and Speed sensor work with the Edge 800?

Asked by: Tandemsr4us
The Garmin Bike Speed and Cadence Sensor is compatible with the Edge 800.
Answered by: REIservice
Date published: 2016-06-24

Will a Wahoo Elemnt work with this sensor?

Asked by: tmitch4
This sensor is coded to work with a Garmin receiver; any working operation with another brand is coincidental.
Answered by: REIservice
Date published: 2016-05-16

I have a Garmin 920XT. Since the watch already records speed what is the function of the Bike Speed Sensor? Should I get just the Cadence Sensor? What is the added advantage of an additional Bike Speed Sensor? Thanks!

Asked by: AMELIA
You do not need the speed sensor if you plan on calculating speed with the GPS function on your Forerunner 920. The speed sensor is a wise purchase if you plan on cycling indoors using a trainer or are going to be in an area where a GPS signal can be spotty (under heavy tree cover).
Answered by: REIservice
Date published: 2017-06-04

Hi! Just hoping to confirm that the Harmon bike speed and cadence sensor is compatible w the Edge 820? Haven't seen that model specifically noted on details or in Q/A. Thanks! Does REI also sell spare batteries? Thanks. 

Asked by: Gserra
This speed and cadence sensor is compatible with the Garmin Edge 820. We do sell replacement batteries for this item on our site. You can find them online here:
Answered by: REIservice
Date published: 2016-10-07
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