Mountain Biking Hartman Creek State Park Waupaca, Wisconsin – May 17th, 2022

Comparing the Cykelstrom Bicycle Power Meter App to a single sided crank power meter
Elapsed Time Moving Time Distance Average Speed Max Speed Elevation Gain Calories Burned
01:14:28
hours
01:12:19
hours
8.08
mi.
6.70
mph
16.40
mph
540.03
ft.
940
kcal
Nice day to ride in the woods at Hartman Creek State Park near Waupaca, Wisconsin. This was a test ride to compare the Cykelstrom Bicycle Power Meter App to a crank based power meter using only a cadence sensor. Speed information came from the GPS of the smartphone. The power meter used as the standard comparison was a 4iiii Precision Pro left sided Shimano XT crank.

Mountain Biking with the Cykelstrom Bicycle Power Meter App

Mountain biking and getting good power measurement data is certainly a challenge. The technology that Cykelstrom depends on is better suited to smooth steady and open conditions, like road cycling. The aggressive characteristics of mountain biking introduce a significant amount of noise to the signals Cykelstrom uses to calculate power. In addition, GPS signals can be difficult to obtain under heavy foliage or obstructions to the sky. Even though it is challenging, Cykelstrom appears to give acceptable data information, typically +/- 25% on average, but errors can be larger depending on conditions.

Remember, that when riding in a heavily sheltered area from the wind that it may be best to turn off the weather data and set wind speed to zero.

I am still studying the differences between full suspension and hardtail mountain bikes and as the data comes in I will share them in my posts. So check back often and if you wish to participate in my study, please contact me, developer@cykelstrom.com

GPS Speed with External Cadence Sensor

CykelstromCrank Power MeterDifference (%)
Average Power177.20142.89+ 24.08
Correlation.36671
Standard Deviation119.86112.23
Cykelstrom Bicycle Power Meter App using GPS speed and external cadence sensor

When using Cykelstrom with GPS speed and an external cadence sensor, you can see that the data distribution is very similar to the crank power meter. This appears to be the best configuration and I recommend using an external cadence sensor.

GPS Speed No External Sensors

CykelstromCrank Power MeterDifference (%)
Average Power182.59142.89+ 27.78
Correlation.33551
Standard Deviation118.68112.23
Cykelstrom Bicycle Power Meter App using GPS speed and no external sensors

When no external sensors are used, the shape of the data is similar to the crank power meter, however there is a lot of coasting and impulse like pedaling that occurs in mountain biking and Cykelstrom has a tendency to overestimate power in these circumstances.

Conclusion

Mountain biking conditions present challenges to smartphone applications that calculate power estimates, but if your are willing to accept the relative error they still provide useful information which further enhances your riding experience. For best results, use an external cadence sensor and if most of your riding is sheltered from the wind, turn off the weather data and set wind speed to zero.

As always, let me know your thoughts.

Happy riding,

Chuck

Chuck

Developer of the Cykelstrom App