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Cog Display


This app calculates the gear ratio that you are currently using based on your cadence and your speed. Since it is impossible to determine what chain ring you are using, the app will display all the estimated cogs. For instance if you have a double chain ring 34/50, it will display the estimated cog for the 34 chain ring on the left and the estimated cog for the 50 chain ring on the right. It wo...


Bug fix (1.0.4): On Edge 520, the display was very small. I believe it is now fixed with this version, but it is hard for me to test it since this bug does not appear in the Garmin simulator.</p><p>(1.1.0): Added support for Fenix 3 watch


  • Edge® 1000 Edge® 1000
  • Edge® 520 Edge® 520
  • Edge® 820 Edge® 820
  • Edge® Explore 1000 Edge® Explore 1000
  • Edge® Explore 820 Edge® Explore 820
  • fēnix® 3 fēnix® 3
  • fēnix® 3 HR fēnix® 3 HR
平均評価: (27評価)

Hybrid Noob

Stumbled upon this and gave it a try on the trainer at first - all good and impressive but surely it can't cope with the gradient changes outside? How wrong I was! I'm incredibly impressed with the accuracy, having just returned from a ride over very varied terrain. Within a second or two the display was consistently showing the correct cog, whether I was powering along the flat or out of the saddle while climbing a steep 15% incline. It now has me wondering quite how it calculates the ratio so accurately, in spite of all the gradient changes, using only cadence and wheel speed??? :/ The one exception is, understandably, when you are spinning out going down a downhill. Of course that's a total non issue given the second you are putting out any meaningful power the display corrects almost instantly. All in all a wonderful little app. For someone who occasionally loses track of the gears and glances down at their cassette this is a nice quality of life addition - if gear display is good enough for Di2 this app is good enough for everyone else!

2018/03/16, Clement_Barthes

Hey Hybrid Noob, thanks for the kudos! To answer your question, it calculates the ratio using error minimization. Instead of coding IF LESS THAN but MORE THAN etc... you can compute the error between the measured ratio and the ideal ratio of each cog/chainring pair. Once you've computed all the errors, you rank them and display the lowest one...Tada!!! This approach always give great results . You can check out my code if you click on the source code link, it's very simple if you code a little bit.

Álvaro Carreras Espallardo

Una aplicación indispensable, me encanta ya que no tengo que mirar atrás para ver en qué corona voy. Gracias a esta aplicación me he aprendido de memoria los piñones que tengo.

Paumier Jean-Michel

Presque parfaite... manque juste deux petites choses : le 12ème pignon et pouvoir visualiser le graphique dans Garmin connect. Merci


Fantastic. It works perfectly. Simply and clear. Thank you so much.

Peter Schneiderhan

I miss the Setting for my 1x12 Speed Chainrings

Nico G

Super application ! Fonctionne vraiment bien et rapidement. Un plus serai de pouvoir avoir l'historique des valeurs / log dans l'activité Garmin Connect Merci !


Bravo et le fait de proposer le code source c'est un super exemple. Reste plus qu'à connecter ça avec un Di et on a une boite auto :)


de la balle , hyper réactif , que du bonheur plus besoin de regarder la roue arrière.....

Alberto Vitali

It works very well. I use it on MTB with Eagle 12V, It's possible to add the 12th cog? Thanks!

Antonio Lopes



Very good. I would prefer to see only the active rear cog number (1-10), and much bigger. Once on the trail it is hard to read the small numbers. Good work, thanks!