Bontrager ANT+ Bike Speed/Cadence Sensor that requires no zipties or tools!


(Update/Note: If you’re looking at this unit, it’s marketed under both Bontrager and Motorola brands. Same identical unit, just different shell.)

It’s funny when you think about it, as much innovation that goes on in cycling computers – there’s been fundamentally very little innovation to date when it comes to the speed/cadence sensors that most of us have on our bikes.  These little pods sit by the crank and watch the world of the wheel fly by.  But up until now, they’ve always been a bit of a pain in the butt.

First, you’ve gotta find just the right spot for it where it manages to trip the magnet on the crank while at the same time your wheel spoke magnet.  Then, you’ve gotta zip-tie the thing on there permanently – hoping you got it right.  And of course, should you want to move the thing later on, you’ve almost always got to cut off the zip ties, hoping you don’t scratch up your expensive bike’s paint job in the process.

So back in September at Interbike (yup, 5 months ago!) I had heard of this new Bontrager ANT+ speed/cadence sensor that didn’t require any zip ties, nor any tools.  I was pretty jazzed.  Now, it wasn’t because I had some unexplainable desire to replace my existing trusty little GSC-10 on my bike.  Nope, I actually wanted it because it made the perfect travel ANT+ speed/cadence sensor.  Essentially, anytime I wasn’t on my own bike I could just attach it in a few seconds and be off and running.

Of course, the unit also work just as well in situations where you had multiple bikes and only one ANT+ sensor (though, I would point out that if you had multiple bikes, you could probably splurge for an extra $30 sensor for each bike, and then leverage bike profiles on your head unit).  But let’s not let logic get in the way here…further, let’s not get too ahead of ourselves.

So let’s dig into it.

I’ve had the unit since back in December and have been attaching and detaching it to everything I can find.  Mostly to see how well it works in the scenario of constant bike swappage.  I couldn’t figure out a way though to attach it to either the shark or my turtles.

So instead, let’s break down what’s included in the box:


You’ll notice four pieces within the box, these four pieces make up effectively three components.


First up is the ANT+ speed/cadence sensor itself.  This is the brains of the unit, and is what transmits to ANT+ devices (i.e. your Garmin, Timex, Bontrager, CycleOps, etc… unit):


The unit attaches to your bike using the industrial strength rubber band pictured below.  If you’re familiar with the Edge 500/800 mount system, it’s the same type of bands.  Solid stuff.


Then we’ve got the crank arm magnet, which swings past the sensor to measure cadence.  Unlike traditional magnets that attach via zipties, this one does require you to remove the pedal to use – but it then snuggly fits on there.


And finally, the ever-exciting spoke magnet for your rear wheel.  This little guy goes around in circles like a hamster on drugs.  But, no tools are required – he just snaps on.


With that, you’ll want to get it all installed.  The main sensor portion simply has an industrial strength rubber band that catches on the two ledges of the unit and wraps around your bike frame opposite the chain stay.


Meanwhile, as noted above, you’ll have to remove your pedal to put on the crank magnet.  It’s a bit too bad they couldn’t have done something here requiring no tools, but I also understand that it does need to be pretty tight.  Nonetheless, most places where you would rent a bike would ask you which type of pedals – so you’d probably have the pedals off anyway (and in fact, in many places you take your own pedals with you).  Of note is that this is the same crank magnet as the Duotrap units.



And finally, the spoke magnet.  He simply clips on with a quick snap:


With that, you’re ready to ride!

I’ve been using this across an assortment of bikes (road, mountain and triathlon) – without any issues.  The unit runs on a standard issue CR2032 replaceable battery, which is pretty much the standard these days for sports devices.  They’re easily found at a grocery/drugstore, and will last about a year.

Since the unit acts as a standard ANT+ speed/cadence sensor, it’s functionally identical to that of the more commonly found GSC-10 (Garmin Speed/Cadence sensor).  So it’ll work with any ANT+ device that supports the cycling speed/cadence sensor…which, is basically every device out there.  Be it from Garmin, Timex, Bontrager, Wahoo, Digifit, CycleOps, Magellan, and more – they all support this sensor type.


It should be noted that with both the wheel magnet and the crank magnet, you can use anything that you might already have on the bike.  Why is this relevant?  Well, spoke and crank magnets can be had for super-cheap.  Like, $1 cheap.  In fact, if you’re a regular contributor to your local bike shops beer stash, they’d probably happily toss it to you.  This is of note if you simply want to move the speed/cadence sensor unit itself quickly between bikes.  As you can see below, on one bike I just have a generic wheel magnet:


Also, many times you’ll find that the rental bike you have may already have the cadence magnet on the crank.

Now, this is also of note if you manage to break the wheel magnet.  The only complaint I have about the unit is that the wheel magnet is somewhat easy to break when removing, if you open the clamshell design in the wrong direction.  Not the end of the world, since a new magnet is only about a buck, but a small bummer nonetheless.


Speaking of breakage, I will note that I did completely destroy one of these units a few weeks ago – though through not fault of the unit itself.  I was testing the Polar Power Pedals and trying to align something else with the back wheel still spinning rather fast (very stupid, yes).  During the process of which I bumped the cadence sensor into the wheel.  With the bike wheel effectively a giant garbage disposal at 245 1,300RPM (yup, that’s how many RPM’s a wheel goes at 20MPH), it slaughtered the sensor in the blink of an eye – shooting it out the back of the bike on a trainer at incredible speed.  This…was the resultant:


But again, rear bike wheels will happily eat anything you throw at it.  Like cookie monster.  I’ve lost a Garmin speed/cadence sensor to one in the past, and I know others have as well.  The nice part is that with the breakaway aspect of it, it didn’t injure my rear wheel or the spokes.

Finally, for those that are curious about size comparisons, I present the GSC-10 and Bontrager quick release speed/cadence sensor side by side.


Also, someone recently asked why I often place the speed sensor arm ‘upwards’ and not ‘downwards’.  Well, it depends on the bike.  In the case of my Cervelo P3C, there isn’t enough clearance between the bike frame and the wheel by placing it downwards, it would rub.  Whereas on my Fuji road bike, there’s still clearance for the downwards angle.  If you can go downwards with the arm, it’s a bit better in the situation where the wheel hits it – since you stand a better change it won’t snap it entirely.

So where do you find one of these magical sensors, and how much are they? Well, they just hit the market a few weeks ago and retail for $59, but I suspect you’ll be able to find them cheaper in due time.  Since they’re relatively new, a lot of shops aren’t directly carrying them yet.  As such, you can pick them up through only a few channels currently. The first is the Bontrager online store, and second would be just about any local bike shop can order them via their distributors.  If they’re ordering it for you, they’re looking for part Bontrager #424634.  I rarely make note of part numbers, but since there are so many speed/cadence sensors on the market, it’s important to ensure that if you pay sixty bucks for this one, you at least get the right one.

As always, if you’ve got questions, feel free to drop them below.  Also note that if you’ve got general questions about speed/cadence sensors – then definitively check out my post: The ANT+ Bike Speed/Cadence Sensor- Everything you ever wanted to know .  And if you’re curious about the Bontrager Duotrap (for frames that support them), then you’ll want to hit up that post instead.

Thanks for reading!


Hopefully, you found this post useful. The website is really a labor of love, so please consider becoming a DC RAINMAKER Supporter. This gets you an ad-free experience, and access to our (mostly) bi-monthly behind-the-scenes video series of “Shed Talkin’”.

Support DCRainMaker - Shop on Amazon

Otherwise, perhaps consider using the below link if shopping on Amazon. As an Amazon Associate, I earn from qualifying purchases. It doesn’t cost you anything extra, but your purchases help support this website a lot. It could simply be buying toilet paper, or this pizza oven we use and love.

Post a Comment

Your email address will not be published. Required fields are marked.
If you would like a profile picture, simply register at Gravatar, which works here on DCR and across the web.

Click here to Subscribe without commenting

Add a picture



  1. JaG

    1300 RPM??? That’s >20 revs/sec, which is obviously far too much (I would definitely notice it on my bike ;-).
    In the article you have linked, 1300 RPM is the speed of the motor and, with 5:1 gearing, the bike wheel is spinning at 257 RPM.
    1300 RPM on the bike would be 100mph ;-))

  2. Anonymous

    JaG got there before me; 1300RPM would have you riding at 100MPH. And 257 RPM is on a 26 inch wheel, not on a 700cc road bike wheel.

  3. Doh! Fixed! Thanks guys!

    245RPM for 700c’s: link to

  4. Anonymous

    hope this shows up on amazon soon, i would love to support you and your site

  5. Knew I shouldn’t have put tn the gsc on the holiday list. Now it just needs to meet an untimely death

  6. Another option for cadence magnets that I personally like and use is to get a round neodymium 1/2″ x 1/8″ (diameter x thickness). This fits perfectly at the very end of the pedal in the crank. A jeweler’s screw driver will pop it out pretty easily. Mind you, this will only work well if you have steel pedal axles. I hear you can get these at hobby and craft shops, but I picked up a bunch of them from Amazon for my bikes and friend’s bikes. It’s very clean (nothing on the crank) and unobtrusive.

  7. hate to tell you but knog had this design first. their designs are great

    link to

  8. Hi Lora-

    The only challenge with the Knog sensor is that it isn’t actually ANT+, but instead only works with the Knog wireless head unit – sorta like many of the other one-off items made in the industry for speed/distance. Which means it won’t work with the huge assortment of head units that support ANT+ (basically everyone but Polar).

    Also, that sensor is speed-only, and not cadence and speed. Cool deisgn though!

    Thanks for dropping by!

  9. Ron

    Thorough as always Ray, but I need someone to explain to me why knowing cadence matters. How does knowing whether I’m at 80, 90, or 100 rpm help me go farther faster? I suspect most everyone hovers around 90 plus or minus 10. We learn in grade school to shift by feel. Runners don’t need to know how many strides per minute they take nor do swimmers know what their turn over is. For me this post raises a philosophical question that you may take as blasphemy. When does an athlete reach an “information point of diminishing returns”?

  10. Hi Ron-

    A good question, let’s take it sport by sport:


    There’s been more debate recently on what is considered an ‘ideal’ cadence, with many focusing on self-selected being ideal for longer distance racing. However, there’s still value in high cadence drills – primarily to aide in sprint scenarios where you may spin high and don’t want the mere act of high cadence to eat significantly into effort (you’d rather the act of high wattage do that). For some folks, watching cadence is a clear indicator of fatigue – especially those that lack a power meter (or even injunction with a power meter).


    It’s fairly well established that the impact of elastic recoil doesn’t really take effect until about 90-92rpm (per leg/foot), which is why most world class runners are aiming for turnover rates (comibned legs) upwards of 180-200. Crazy stuff. There’s something to be said for pace to cadence ratios and that at slower paces it’s just not as natural, but most research these days finds significant benefits to higher turnover in proper running technique.


    This is probably the one group that knows their turnover the best. Most competitive swimmers would be able to tell you their strokes per length, with the aim partly to reduce the number of strokes per length, which indicates better technique such that you’re increasing the amount of pull per stroke. Of course, there’s a careful balance between ideal strokes per lenght (cadence) and speed.

    Hope this helps a bit!

  11. Ron

    Thanks Ray. I will try to keep an open “to more information” mind, but I’m still skeptical. I know I’m fatiguing when I can no longer stay on an equivalent rider’s wheel-of course while training, not racing. :) Cue Paul Sherwin, “The elastic has snapped.” And I get the running turnover and swim stroke points, but still, they race gadget free. Just to push the point, I wonder if a pro cyclist has ever said, “Coach, I was checking my cadence when I missed that break.” I’ guess I’m a hopeless minimalist, racing Canada this August with just my Edge 200 and Timex Run Trainer-sans heart strap. I love your blog and don’t begrudge anyone their tech. Maybe I’ll swear off perceived rate of exertion if I blow up on the run.

  12. I agree in a lot of cases on perceived. A race is a race, he with the fastest time is the winner, regardless of what cadence your at.

    The goal those of most of the cadence/turnover metrics is mostly around training, and training ones body to be in the optimal zone. For some (Olympic athletes), that comes after years of training and knowing what that ‘feels’ like. For the new runner/cyclist/swimmer however, they may not know that a 50RPM cadence isn’t the most optimal way to pedal through their race.

    Good luck this summer! Canada’s an awesome course!

  13. Anonymous

    thanks – I’m going to go out and get one of these.

    Top Tip…always remember to use 2 wheel magnets – you go much faster that way ;-)

  14. Hi dc,

    Do you know whether there are also smaller ant+ speed/cadence sensors available? They are all so bulky / so large!!!! Isnt there one which is more subtle?

    Best regards Ruud_G

  15. Do you know if this works with the older Edge 305? It’s not listed on the Ant+ site. But the DuoTap is. ??

  16. Yup, the Edge 305 is ANT+ enabled, and works with the GSC-10 – and thus also works with the Bontrager. Enjoy!

  17. Anonymous

    This item here:

    link to

    looks very much like a clon. Just fyi, as it seems impossible to find the Bontrager one around Europe.

    Keep it up

  18. Yeah, the Bontrager one is a common OEM unit made by an Asian company that does ANT+ work. All ANT+ partners can leverage it and rebrand it. Bontrager was effectively just the first to get to market with their branded variant – but expect to see most rebranded ANT+ speed/cadence sensors start to use it shortly. Basically just like you see on the heart rate straps – all the same unit – just a different logo on it.

  19. link to data/B007KJ1RNI/ref=de_a_smtd

    Here is the Motorola version at amazon. Cant wait to try it out. If I buy any amazon products through your link do you get compensation? I would love to support your great site. Thanks

  20. Very nice.

    Yup, any Amazon product through any of the links. i.e. using the big Amazon button in upper right > then search for Diamond Rings and purchase = support site.

    Alternatively, here’s the tagged link for the Motorola variant:

    link to

    Thanks for the support!

  21. Anonymous

    Now that you’ve had a few months to try this out, how does it compare to the Garmin unit? My Garmin sensor inexplicably stopped working, right before a triathlon, and it was only about a year old. Do you think this one will last longer?

  22. It still works fine for me. But then again, so does/did my Garmin sensor. On your Garmin sensor, did you try swapping out the battery?

    I have some from years ago without issue.

  23. Anonymous

    Yes, I’ve changed the battery without a problem. I’m thinking that somewhere along the way transporting the bike something must have happened, because it just stopped working. I think I’ll try the Bontrager.

    Love your blog, by the way.

  24. Was surfing for answers and your blog came opp (surprise! :D) An old post this, but was a bit curious. I got a bike (fully) that has a bit of a distance between the wheel and the pedal, rendering it almost useless to mount a speed/cadence sensor on it because cadence magnet will need to get mounted above the pedal bolt and the speed sensor will need to be mounted at the outermost part of the spoke. A couple of swaps later the magnet is lost. Even tried to loctite it. So back to my question. Would the Garmin units pick up a cadence sensor and a speed sensor (two units). And if so which of them (garmin units that is) will allow that?

    Have you been testing the Fenix (yea I know big F! ;) with the different brands of Ant+ sensors?

  25. Yes and no. If the units are true speed-only and cadence-only ANT+ sensors, then yes, they do understand them. but if you’re talking taking two speed/cadence combo sensors and trying to use only half of each – then no. You can only pair one speed/cadence combo sensor, whereas you can pair one-each speed-only and cadence-only sensor.

    Fwiw, you can usually pickup the magnets for a buck or two at most local bike shops.

    The newer Garmin units (FR310XT and newer, or Edge 500 and newer) will allow speed-only and cadence-only units.

    As for Fenix, yup, been testing it. Good stuff. No issues with any of the different ANT+ brands with it yet (I’ve been using Bontager currently) – they all just work.

    • Maddy

      Ray, I tried Bontrager ANT+ Bike Speed sensor only with Garmin Fenix FW 4.00 and it’s not working (sensor is OK, paired succesfully with Ambit2). Does it mean Fenix is working with Speed AND Cadence only sensor, not purely Speed sensor? I do not need cadence data and sensor is more durable without additional “arm” which Speed/Cadence sensors have. Thanks for help!

    • I didn’t bring my Fenix2 with me on this trip, but I was pretty sure that’s odd it’s not working. I’d post a note to the Fenix2 post and see if someone else has the same sensor and can validate it on the last firmware.

      I do have the Bontrager speed-only sensor on my tri bike (in addition to a combo sensor), and I’m reasonably certain I tested that at one point.

  26. Anonymous

    Reply to Chis@25
    The Wahoo transmitter might work better (there is a wire separating the cadence and speed sensors).

    link to

  27. Anonymous

    Oh, the Bontrager type transmitters have leds that let you align the magnets with the sensors without needing to look at the head unit. (I have no idea if other transmitters do that).

    I was a bit concerned that the rubber band holding the transmitter to the stay would hold. 3000 miles and there hasn’t been a problem. (It can be a bit of a bother putting on the bike.)

  28. Indeed on the Wahoo front. I played with seperating some and some extra wire from home depot. In talking to Chip at Wahoo – it’s definitely doable since that’s all that’s between those two. Pretty, no…but functional, yes.

  29. I have this sensor. Two problems with it. One is that it was always coming loose until I ziptied it onto my frame. And the first battery lasted 3 months. Other than that it’s been great. I use with both the Node 2.1 and Edge 500.

  30. Do you have any idea when Clever Training is going to get some of these in stock?

  31. Asking now… thanks for thinking of me!

  32. Just following up to see if they ever gave you an answer for stocking this. :)

  33. Jon Osborne

    Hi, I bought this in UK from Pedal On. Main reason I got this over Garmin is ability to use on 2 bikes and swap easily? I have installed on one bike and am not convinced it will stay on that well. The rubber band keeps popping off. Managed to get it in place and went for a test ride. It did stay on but constantly looking at it whilst riding. SO got home and secured with cable ties, which defeats object of it?!
    I felt its not that bad cutting and using new ties when want to swap onto another bike, and at least wont fall off. Jon

    • DC Rainmaker

      The trick to the rubber band is slightly turning it inverted, so when you hook it on the hook, it starts to peal back and end up ‘straight’. I realize that explanation probably makes zero sense beyond my head, but it at least works in my head.

      In general, I find that if it stays put for 2 minutes, you’re good forever. :)

  34. PaulMack

    I just got a computrainer, and thought this might be handier to pop off and on when deciding to go outdoors (I have the garmin 800).

    My question is, can I leave the crank magnet on from the garmin ie will it affect the ct’s spin scan?

  35. ericmin

    I recently bought this sensor but the rubber band seem pretty tight on my Cervelo S3 stays. I’ve had to move it the sensor towards the rear hub in fear that the band might snap. Should I be worried. Do you know if these bands come in any other sizes?


    • DC Rainmaker

      They are pretty snug (sometimes super-snug). I’m not aware of any other sizes unfortunately. I’ve generally found once I get it on there, it’s good though.

      Typically the unit is as close to the end of the crank-arm as possible.


    Any hints on getting the cadence piece to sync up and work. The instructions indicate a green light will flash when it is syncing. I could not get it to flash manually or once on my bike. Thanks

    • DC Rainmaker

      It sounds like you may have an issue with the magnet passing the sensor. If you just remove the magnet and pass nearby the sensor, does it light-up at all? If not, try swapping out the battery first (even if new, sometimes you just get a bad battery).

  37. carson

    If you don’t use the crank arm magnet for cadence, could you mount the sensor on the front fork and the spoke magnet on the front wheel? I’m wondering how this could work with a disc wheel…Quarq + Joule without GPS requires ANT+ speed sensor….but would this work on the front wheel? Thanks!

    • DC Rainmaker

      You could, though you won’t get any speed numbers while indoors (you may or may not care about that). On the disk wheel however, what most folks do it just super-glue a tiny magnet on the rear wheel. Works pretty well. :)

      You can pickup some rare earth magnets on Amazon that are the size of half a pencil eraser or smaller and easily trip the sensor. I’ve got a few that I use for random things and they cost just a couple dollars.

  38. dabtech

    This may be a silly question, but I assume the rubber band is not exerting enough force to compromise a carbon seat stay?

    I just got my first carbon bike, and I’m a little (maybe overly so) concerned about wrapping things exerting force around any of the tubes, but the idea of being able to quickly move this unit between bikes is intriguing.

  39. I have the same issue with my sensor as one of the previous commenters; my cadence won’t register. I changed the battery, made sure the magnet and pedal band all passed directly behind/in front of the sensor. I double checked my Garmin FR70 settings to be sure it was set to register cadence. Still no joy. While changing the battery, I saw the little red light come on once, but never again… Is there an “on” switch magically hidden? Is my Garmin hosed? Would it be better to use the foot pod to register cadence? (Speed isn’t important right now; Coach wants me at 85-95rpm.)

    • One thing to try is to ever so slowly rotate the arm forward while swipping a battery (any magnet, kitchen is fine) past it repeatedly. See if at any point the sensor starts picking up again.

      I’ve seen some issues on similar designed units by other companies where there’s a ‘dead spot’ in the arm rotation and it won’t pickup anything.

  40. Thanks!! Appreciate your time. :) I’ll be supporting this site; super helpful to this brand new cyclist.

  41. BQ

    Has anyone had trouble getting the speed to work with this unit? I bought the Motorola branded version and just put it on my bike yesterday. I can get the cadence to register, but the speed just shows 0. Even when I wave the spoke magnet by the unit, the red light does not light up (green light for cadence does). My plan is to get a new battery and see if that helps, but could I have a bum unit?

    • I’ve seen this on a few other brands with identical designs. It tends to be an issue with the sensor arm being in a ‘dead-spot’. I’ve found that if you move the unit (in whole), and then re-adjust the sensor arm, you can get out of the dead spot. That can introduce other issues, so it’s a bit of a finicky thing. But try completely changing the sensor arm position and doing the magnet wave, and see if that fixes it (to validate if there’s any position it works in).

  42. Jacquie

    Red and green lights? I am trying to get this to work with my Garmin 810 (now that I have the map working thanks to Ray and everybody else) but it doesn’t seem to transmit any data. Yes, I did pair it with the Garmin. The fact that there were NO instructions whatsoever packaged with the sensors and I can find none on the Internet does not help. To me, that’s a big strike against Bontrager.

  43. Les Borean

    My GSC-10 came to an agreement with my soft Garmin HRM strap to both stop working at the same time. Per your suggestion in another posting, I have ordered the Polar strap to replace the Garmin.

    And here too, I am thinking of ordering the Bontrager cadence sensor to replace the Garmin. One question, though: With only a rubber band mounting, I am concerned that the sensor will shift position during a ride and get creamed by the pedal or, on the other end, might twang a spoke. Have you had any problem with the Bontrager not staying put during rides?

  44. BillM

    I have one of these branded by Trek and plan to fit it soon, funnily enough the ability to quickly remove it is something of a disadvantage to me as it is just way too easy for a thief to remove it should I park up in street to go shopping. Ill also be parking my bike up at work. Im also not keen to see it explode in the spokes should i hit a pothole and dislodge it. My solution will be to have one zip tie on just in case the elastic slips but to have a steel wire such as brake cable looped through second cable tie hole, this steel wire will then be crimped so that at least the thief will have to use tools to remove it and hopefully this will be some deterrent.

  45. Les.Bo.

    Just ran with mine for the first time today. I did appreciate the clever mounting sans zip ties. But I had 2 rear flats today, and both times when I removed the rear tire I knocked the sensor off. Maybe I have to be more careful removing the tire.

    Referring to the top picture in this page, I positioned the speed sensor arm pointing downward instead of upward. Don’t know which is the “right” way, but in the down position, should the arm catch a spoke, the results would be less cataclysmic with the arm pointing downwards.

    The unit worked fine with my Garmins 305 and 500. I hope it lasts longer than the Garmin sensor did.

    Thanks for the tip about this unit.

  46. Doug

    Hi Ray
    Any idea about suitable replacement bands? I have a canondale MTB with gigantic box stays and I suspect if the band can be tight on general road bikes, the girder-stays will stretch it too much. Ideally I’d use a bigger band

    • Hmm, not sure where you can order those exact replacement ones (probably from Bontrager). However, if you need just similar ones, grab a box of the Garmin Edge mounts ($9 for a huge box of them), which are similar and actually a bit stronger.

  47. Ray,
    have you ever experimented with mounting one of those (at least the cadence part) on a stationary/spinning bike?

    • Indeed I have actually.

      I spent the better part of a few hours one night at a hotel gym in Mexico city trying to figure out how to do it. There’s two issues, and neither are easy. First is where to pod the pod itself, and second is actually the magnet. The magnet is somewhat easy in that you can solve that by glue to your shoe.

      The pod is tricky in that you almost need some sort of large ‘belt’ that can loop around the machine and hold it in place near your shoe.

      Honestly, I think the problem will be solved with the Wahoo RPM, which in theory can be mounted on your shoe and provide the same. I’ll see more on that later this week.

  48. RS

    Hi Rainmaker…. Awesome reviews….
    Can you tell what all sensors work with the Motoactv???? It is a confusing with all the ANT+ compatible devices on what all works. Does the Garmin GSC-10 and Bontrager Duo Trap work with the Motoactv??? Seems like the GSC-10 is a lot more accessible (popular) and maybe a good choice for me????

  49. seth

    Hey, Any suggestions for keeping the speed magnet from slipping down the spoke. I’ve got it on a Trek 1.5 and it keeps slipping down to the reflector on the tire and I’d like to avoid having to reconfigure the whole setup (main unit and cadence sensor).

  50. Les Borean

    If you’re talking the Garmin speed magnet, just tighten the screw a bit more until you don’t the problem goes away. But then, whatever magnet you’re using, you’ve probably already tried that.

    Try another brand of magnet, they’re cheap. Just google on “speed magnet”, and you will get a number of hits. I find that the Garmin one works well for me, although I did have to go through a cycle of tightening the screw a bit more.

    Which gets me into a bit of a rant on this. With all the technology available these days, I would think the designers could come up with a more elegant method to sense wheel rotation than a dorky magnet mounted on a spoke.

    For example, your typical computer mouse can sense movement of a surface, even a smooth surface. This technology could be used to sense the movement of the side of the rim.

    Or use some proximity sensing technology that could sense spokes passing a certain point ( without magnets).

    Just a thought, after years of dealing with mangets.

  51. Les Borean

    I bought this cadence sensor when my Garmin sensor deep-sixed. I was hoping that the Boutrager unit with its unique mounting method would be more stable than the Garmin, which needed frequent adjustment. What I personally found was that this unit was no more stable and I still had frequent cadence drop-outs due to sensor misalignment. The advantage of the Boutrager was that since it was mounted with rubber bands instead of wire ties, it was easier than the Garmin to adjust on the road.

    Still, it was a PITA to deal with. When I ride, I want to ride, not deal with equipment issues. After dealing with the Boutrager for a number of months, I took a look at the mounting for my “Light and Motion” head light. Its mounting was very solid, utilizing a thick rubber band, with spaced holes not unlike a belt.

    I thought if I could get one of those mounts and hack it onto the cadence sensor, I might finally have a good solid mount. Well, it turns out that Light & Motion does make the mounting for their light separately available.

    link to

    I took the chance I would be able to make this scheme work, and ordered it. I drilled holes in the mount that allowed me to securely attach the sensor with wire ties. Then I mounted the assembly onto the left chainstay of my bike.

    Since that time I have taken the bike on 2 rides totaling over a hundred miles, and the sensor assembly remains solid and has not once required re-setting. So far, so good. This is more mileage than either the Garmin or the Boutrager mounts ever took me without needing to be adjusted.

    From my previous posting, it looks like Dropbox links don’t work on this site. Just in case though, this link should take you to a picture of the setup:
    link to

  52. Eugene


    I’m a huge fan of your review site. I have a question regarding this sensor. I just bought a new Bianchi Intenso and the chain stay design is curved and not very suitable for mounting my Garmin sensor. In fact, the best the local bike shop could do was use a flat rectangular magnet taped onto my spoke. They also had to use another cylindrical magnet behind the pedal to extend its reach and did a pretty poor looking job of zip tying the sensor onto the non-linear unconventional design of the chain stay. Do you think this Bontrager sensor would be a more appropriate fit for a Binachi Intenso chain stay? Thanks!

    • It might be. On the flip side you might want to wait a few weeks and pickup the new Garmin sensors. These don’t require any magnets and are based purely on accelerometer (sorta like the Wahoo RPM, but for both both speed and cadence). See my Edge 1000 post for a bit more details there.

  53. Chris

    Hi there, just found this thread..I have the duo Bontrager on my Trek and it won’t connect to my suunto Ambit 1…any one had this issue (resolved) ?

    • Hi Chris-

      Getting ANT+ sensors paired to the Ambit series can be a bit finicky. In general, you may need to try it once or twenty times to get the initial pairing completed. Put the watch directly next to the sensor (like, touching it). And then keep pressing retry. I promise it will eventually connect, it just may be super finicky on initial pairing.

      After paired you’ll be good to go.

  54. Mat0x4e

    Same item, isn’t it ?
    Runtastic version

  55. ahmed khaled

    hi, could you tell me your opinion on the bontrager node 2.1 with it’s cons and pros if possible and if you know if i can review my data on my laptop with it and also recommend me other alternatives and if you think a gps computer will be better

    • I haven’t used the 2.1, just the older version. That said, for the 2.1 price of $139, I’d really recommend looking at the Garmin Edge 200 instead. It’s cheaper and far more functional. Also, the Node doesn’t download to your computer, whereas the Garmin Edge does.

  56. Zac

    Ray –

    Love the site. I recently got this speed/cadence sensor combo. I’m having trouble getting the cadence to read. I’ve checked the main pod for function by using a fairly strong magnet and passing it close to the face and get the green indication light. When using the magnet that attaches to the crank arm, I can’t get the light to come on or cadence data unless I lean the main pod dangerously close to the crank arm. Any suggestions?

    • It does need to be really close (within a few millimeters).Did the magnet that came with it not work?

    • Zac

      It seems to only work when it actually touches (or just about touches) the main pod. Not much of a magnet it appears. Installation instructions were very lacking (none provided).

      Have you had any problems with coming in contact with the pod while riding? I’m considering returning and going with a different type, as I don’t want to destroy this one and lose my investment!

    • Theo

      Make sure your magnet is installed the right way around. Some magnets (such as the one in IMG_3273) sometimes get installed inside-out by people and then it does require almost-touching to get it to register. I have no experience with the Bontrager ones, though. However: You can mix and match these magnets as you please. If you already have a magnet on your wheel or crank from a previous sensor installation then you can most likely use it instead of the Bontrager provided one. I use an 8mm neodymium supermagnet on the inside of my pedals or taped to the inside of the crank, instead of any of the sensor vendor magnets.

    • Zac

      Theo –

      Thanks for the reply. I have confirmed that I have it on correctly, per the photos above. I may have to try to find a rare earth magnet. It seems like the magnet installed in the crank band is tiny. I may try to rig something up. Thanks again.

  57. Paul

    Hi all, I have the Suunto Ambit3 which uses Smart Bluetooth and not ANT+…does the Bontrager Combo come in a Bluetooth version? Need something to use with my Scott Foil so cannot use the internal frame mounted unit. Cheers

  58. Artur

    So was riding yesterday as usual, and didn’t notice any problems, but the cadence fallout at some point. Kept pedalling and forgot about it at the end of the ride. At home, looked at some average numbers from the ride briefly, but did not go into the detailed graphs of each parameter. Today, while washing the bike, noticed the speed/cadence sensor missing off the bike. Couldn’t find it anywhere. Checked the data from yesterday’s ride – indeed, cadence fallout happened on a particular intersection.

    Given it’s holiday for us today and my wife wanted to go out (car) riding / walking somewhere, we went on a ride to the other end of our megapolis and found the Bontrager speed/cadence sensor exactly where cadence dropped off on Strava / Training Peaks (link to Amazing way to find something you’ve lost!

    And why am i writing about this here? Before going out today, I was already reading up on all sort of DCR reviews of speed/cadence combo sensors and thinking what to buy next, and when came home saw this page still open and laughed! Well, seems I still have a sensor for some time. Good luck to all others using it!

  59. Saron Matias

    If you use the sensor with the speed sensor arm on the downward position, it probably will not break when accidentally hitted by the wheel (I use this way).

  60. Peter

    Hello, i h
    Bought the bontrager ant with the cadans sensor but for whatever reason it doesn”t work. My cadans stays on 0. Does anybody has an idea?

  61. Peter

    My bontrager 300 with ant cadans sensor does not show cadans. Anybody has an idea?

  62. Bryan

    Bontrager crank magnet is not strong enough. I have 2-3 magnets just snapped off during the ride. The rubber is easily worn off under Australian sun.

  63. Mike Whitehouse

    Great work Rainmaker!