Getting Cadence Data While Spinning

UPDATE: Checkout the results of 18 months of spinning on Google Earth HERE

Do you use a GARMIN Forerunner 305 to monitor your heart rate while spinning? Are you interested in cadence training? The following details how you can use your GARMIN Forerunner and other devices that use a wireless connection to collect cadence data, without modifying your spin bike at the gym/sports center.
First you need the “GARMIN Speed/Cadence Sensor (GSC 10)” which connects wirelessly to the Forerunner 305. Normally this is connected permanently to your road bike. In this project the goal is to be able to use it in a spin class on a spin-bike shared with others.

Bill of materials:

  • Garmin Forerunner 305
  • Garmin GSC-10 Monitor and magnet
  • 2″x4″ metal bracket
  • 2- 4″ cable ties
  • medium binder clip
  • thin no-skid carpet pad
  • Aluminum seam binder or doorway strip 36″
  • 12″ Elastic shock cord(not shown)
  • rubber cement (not shown)

the bracket

Drill a hole or two depending on the size of the bracket that are close to the bottom edge to mount the cadence monitor as shown below using the cable ties.


You may need to adjust the positioning of the “Speed Sensor” the arm that sticks out to match the positioning shown. The “speed sensor” is not needed.


Cut a strip of the no-skid carpet pad to the width of the aluminum binder/strip. The the photo above the strip had been bent to the shape of the chain guard of the spin bike and the padding has been glued using rubber cement. The padding is aligned with the portion that is in contact with the bike.


Use the binder clip to attach the cadence monitor to the strip.


Now the assembly can be mounted on the spin bike using the shock cord. The overall length of the bar/strip may need to be shorten depending on the spinbike.


In this photo you can see the magnet on the pedal and cadence monitor below the bar. The trick is to align the magnet with the sensor. The magnet is strong enough to hold on to the pedal, a twist tie can be used if necessary.


Mounting the Forerunner on the handle bar is easy, using a short section of pipe winterizing foam.

Follow the directions, that came with the cadence unit, for setting up the Forerunner to sync with the cadence monitor. Give the pedal a spin and then check to see if the unit is syncing with the watch, you may need to make some adjustment to get the right alignment.

When running on a stationary bike it is important that the mode of recording is changed from “Smart Recording” to “Every second”, as “Smart Recording” using distance travels to determine when data is actually recorded. (Settings -> General -> Data Recording(scroll to bottom).


This setup allows for some flexability in how the part are connect. Once familar with the setup and alignment a more permenent connection between the backet with the Cadence unit and the bar strip is recommended. Lastly after a good workout it is easy to forget the magnet that is on the pedal, I added a label to the bar “Remember the Magnet”, (note: on Amazon I found a source that sells a kit with replacement magnets.)

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16 Responses to “Getting Cadence Data While Spinning”

  1. Doc says:

    Will the GSC10 cadence sensor pair with the newer Forerunner 405CX? I can’t seem to find that Smart Recording vs Every Second setting. Much thanks!

  2. dmcoxblog says:

    A quick scan of the 405CX manual indicates that the 405CX will work with the GCS 10 Cadence sensor Page 33. As for Recording modes Smart verses Every Second, it does not appear to have that option, As a substitute using setup for running rather than bike, as I believe that it records data when there is a change in location, running the gps indoors on a spin bike will simulate changes in location.

  3. Proactol says:

    I would suggest you continue writing more posts, this would make your blog even more interesting.

  4. Love that bing, fascinating information. Keep up the good work.

  5. cesar says:

    Is not easier to install the cadence unit in the shoe/ankle and the cadence magnet in the spinning bike?

  6. cesar says:

    Do this work for calories burning calculation on the forerunner305?

  7. dmcoxblog says:


    The calories burned is not accurate as part of the calculation is based on distance traveled.


  8. dmcoxblog says:

    I have found that the distance between the magnet and cadence unit is critical and very small. It needs to be 1/2 inch or less. I also have substituted the garmin magnet with a large ring magnet, which is a little easier to align.

  9. Bruce B. says:

    dear dmcoxblog, what sized ring magnet did you use and where did you get it to use with your spinning/garmin hook up?

  10. dmcoxblog says:

    The ring magnet is about 1.25 inches across, the hole in the middle a little more than a .25 of an inch. I bought my at an Ace hardware store, in the section that has lot of pull out drawers with all kinds of screws, nuts and assorted small hardware.

  11. Claudette says:

    Great idea how did you get your cadence set correctly since different spin bikes have different ratios of fly wheel revolutions to pedal crank revolutions, I have Garmin FR60 and the Garmin GSC-10 on my Greg Lemond Spin bike? Any ideas would be greatly appreciated!

  12. dmcoxblog says:

    I maybe mistaken but I understand that cadence is simply a count of the pedal strokes. So there is no way to set the length pedal crank.

  13. Claudette says:

    Thank you very much for your response… that what I was looking for…

  14. Koos Verhagen says:

    I use a Garmin 310XT on my spinning bike to measure heart rate and cadence. I use the Bontrager ANT sensor ( for cadence attached to the bike with velcro near the bottle holder. Just set 310 to bike, disable gps and enable in ‘Settings’, ‘Bike Settings’, ‘ANT + Spd/Cad’ menu, ‘Yes’, ‘More’, ‘Type’: ‘Cad sensor’. Works like a charm and no need for complicated constructions, just a piece of velcro.

  15. Jeff Schmitz says:

    WOW, I’m getting a spin bike with no cadence, and I just happen to have a GSC Monitor and magnet laying around that I got with my garmin 310 XT. What a happy coincidence. THANK YOU for this great write up. Off to the hardware I go.

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