Garmin wireless cadence sensor review Feature

Garmin Magnetless Cadence Sensor Review

Whilst researching a solution for adding cadence to my second bike I noticed Garmin had recently introduced a new magnet-less range for both cadence and speed detection to pair wirelessly via ANT+. Perfect!

The brand new sensors are different to the previous GSC-10 ‘Combi Sensor’ (reviewed by Ben) in that motion is now detected via an in-built accelerometer rather than a chainstay mounted unit triggered by magnets rotating on the spokes and/or crank. With the inclusion of accelerometer technology, the cadence sensor is much smaller and can be mounted inconspicuously behind the bike’s crank arm.

Here I have tested the cadence sensor only. A separate speed sensor (which mounts to hub of the rear wheel) is also available and tested here. N.B. if you do wish to go magnet-less for both speed & cadence you will need two separate sensors (they can, however, be purchased as a pack).

Garmin Magnetless Cadence Sensor Review – Opening the Box

Garmin magnetless cadence sensor review

Garmin Magnetless Cadence Sensor Review

The the box comes as a nice compact package, small enough to fit through your letterbox. It’s very neat but still providing sufficient detail of what to expect inside.

Garmin magnetless cadence sensor review

Once opened up you’ll discover three parts; instructions, selection of elastic bands & bubble wrap!

Garmin magnetless cadence sensor review
Opening up the padded black package and you’ll soon find the unit itself. It’s impressively small.

The Cadence Sensor

Garmin magnetless cadence sensor review

The unit on its own looks like this.

Garmin magnetless cadence sensor review

With the elastic band.

Garmin magnetless cadence sensor review

A closer look at the rear and how the two point elastic band is secured.

Garmin magnetless cadence sensor review

And the complete mounting on my crank arm (non-drive side). I use an FSA crank which required the medium of the three elastic bands.


Garmin magnetless cadence sensor review

You’ll see from this picture why I began my search for a new sensor! I’m often testing multiple products meaning I need to utilise both ANT+ and Bluetooth connectivity. Previously I had successfully mounted two magnet-based sensors. Room was limited and the sensors were prone to falling out of alignment between rides if I happened to knock one during storage etc.

Garmin magnetless cadence sensor review

As you can see, these sensors required a fair bit of alignment with 2 magnets required for each. The new sensor from Garmin has now provided me with the perfect solution whilst also allowing me to move the spare GSC-10 Combo to my second bike.

The only downside, however, is that not being a combo sensor I am now only detecting cadence via ANT+. This is only a minor trade-off, as I do most of my riding outside and prefer to utilise the GPS data for speed analysis in any event. I have the option of buying the separate speed sensor at a later date should I start doing more indoor training.

Test – Magnets v Accelerometer

So with my bikes tidied up it was now time to test. Fortunately, I retained the Bluetooth sensor so I was able to pit the new Garmin against the traditional magnet sensor all in the same bike ride. Here are the results using the Garmin FR620 paired with the new magnet-less sensor along with the Polar V800 equipped with the Wahoo Blue SC.

 The first graph shows the Garmin.

Garmin Magnet-less cadence sensor

Screenshot from Garmin Connect

The second graph is showing the magnet based Wahoo Blue SC.

Garmin Magnetless Cadence sensor review

Screenshot from Polar Flow

Over an 18 minute ride the graphs are near identical. In the analysis back in both Garmin Connect and Polar Flow both sensors showed exactly the same average and maximum cadence. The only difference appears to be a dropout appearing at 13 minutes 25 showing on magnets but not the Garmin. I actually think that in must be the Garmin that was correct as, at that point on the ride, I would have been in full flow.

A few days later I’ve added a further comparison again using the same sensors.

Garmin Magnetless cadence sensor review

Above is the Garmin. Below is the Wahoo Blue SC.

Garmin Magnetless cadence sensor review

A few extra spikes are noticeable over the longer ride but all-in-all, two extremely impressive comparisons.


According to the product information on Amazon the new magnet-less sensor is compatible with the Garmin Edge 1000, Edge 500, Edge 510, Edge 705, Edge 800, Edge 810, Forerunner 305, Forerunner 310XT, Forerunner 620, Forerunner 910XT, FR60 and FR70.


The ease of use and convenience factor has already sold this product to me. I also think this could be the perfect method for detecting cadence on a mountain bike where tucking the sensor away becomes even more important. In short, the new cadence sensor does exactly what it is intended to do without any fuss whatsoever. Once it’s mounted you can forget about it even being there. It’s also extremely easy to switch to another bike without the need for cutting and removing cable ties or any further calibration. So far I can’t fault the accuracy either.

To compare with the GSC Combi Sensor you can read the review here . To complete the se you can read about the Magnetless Speed Sensor here.



  • Magnet-less
  • Easy installation & mounting
  • Universal application
  • Compact
  • No moving parts
  • Accuracy


  • No combo option
  • More expensive than the GSC-10
  • That’s about it!


It’s worth bearing in mind that this sensor utilises ANT+ wireless connectivity so will not encompass a one stop shop for all cycle enabled devices. If you are using ANT+ already (i.e mostly Garmin devices) this could present the perfect solution for cadence particularly if you want to eliminate moving the parts. For me it has offered the perfect solution as I simply love the mounting system and pure simplicity. If you are in the market for both speed & cadence then the previous GSC-10 does still offer the more cost-effective solution. Having said that, the cost saving becomes minimal if all you need is cadence combined with the GPS tracking on your paired device. In that scenario you can opt for this sensor alone without any compromise on accuracy.

I am very happy with this little device!

Buying Options

I want my reviews to be as independent as possible. On that basis, I thought a link to Amazon would provide the most impartial method of you looking at other user comments should you be considering a purchase. You can also find the product info direct at Garmin


  1. Hi. I have a technogym excite bike and have a real close clearance situation. If you still have the device could you possible measure the height of the device in mm for me? I cannot find a single instance anywhere of it being mentioned.

    • Hi David. I’ve just measured (it’s still on my TT bike) and mounted to an FSA crank it protrudes about 8mm. Off the bike it was just over 8mm as my crank arm is slightly recessed. Bear in mind also that you can position this furher down the crank arm than a normal magnet sensor, which may assist your clearance issue.

  2. Thanks Tim, that’s about a third of an inch should work. I will be anxious to see your full review of the 920xt coming up. It sure looks gorgeous on your intro.

  3. Pingback: Garmin Forerunner 920XT Review | TriedOnline

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  6. Hi There, I know your post is an older posting about the garmin cadence sensor for bikes. I’m very curious — if you were to mount this say, on a kayak paddle, do you think it would measure the number of paddle strokes per minute? [Could you try it for me … say strap it to a stick and paddle as if in a kayak at about 80-90 strokes/min (L then R x 40 times).

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