Wiouwash Trail Ride with Family - April 29th, 2022 - Cykelstrom Bicycle Power Meter App

After dinner we decided to go for a short bicycle ride and as expected I collected data using the Cykelstrom Bicycle Power Meter App.

Click on the map below to go to the “Developer’s Strava” account where you can observe the data visually.

Elapsed Time	Moving Time	Distance	Average Speed	Max Speed	Elevation Gain	Calories Burned
01:08:00 hours	01:02:08 hours	10.98 mi.	10.61 mph	18.52 mph	93.83 ft.	401 kcal

For this ride I rode my Trek Top Fuel 8 with a single sided 4iiii Precision crank power meter on a Shimano XT left sided crank as my measurement standard. As this was a family ride there were times where we were just screwing around, going in circles and many stops. I think this has a tendency to distort the data.

External Speed and Cadence Sensor

I used the cadence information from the power meter as it would be redundant to have another external sensor.

	Cykelstrom	Power Meter	Difference (%)
Average Power (Watts)	100.2	87.4	14.6
Correlation	.7147	1
Standard Deviation	65.35	72.29

Table contains data for external speed and cadence sensors

External Speed Sensor and No Cadence Sensor

	Cykelstrom	Power Meter	Difference (%)
Average Power (Watts)	107.9	88.16	22.4
Correlation	.6191	1
Standard Deviation	60.64	72.17

Table contains data for external speed sensor and no cadence sensor

GPS Speed with Cadence Sensor

	Cykelstrom	Power Meter	Difference (%)
Average Power (Watts)	76.10	87.40	– 12.9
Correlation	.7468	1
Standard Deviation	48.41	72.29

Table contains data for GPS speed with cadence sensor

GPS Speed with No External Sensors

	Cykelstrom	Power Meter	Difference (%)
Average Power (Watts)	81.58	88.16	– 7.5
Correlation	.6768	1
Standard Deviation	43.73	72.17

Table contains data for GPS speed and no external sensors

Discussion

This was an interesting ride to look at the data. There was a considerable difference between using an external speed sensor and the GPS speed data. The external speed sensor data over estimates the crank power meter. In this case, I am going to remeasure the circumference of my rear tire and make sure the value agrees with the ride parameters in Cykelstrom. An error like this can have a large impact on the accuracy of the power estimate by reporting a higher than normal speed.

When using the GPS for speed information Cykelstrom under reported the power estimate, however, it is much closer than the prior. The highest correlation was when I looked at using GPS speed information with the use of an external cadence sensor and this is reassuring. Some factors that may have an impact is that this was not a training ride and there was a lot of goofing around, tight circles and multiple stops. I believe this also plays a role.

Conclusion

Even though this was a pleasure ride, using the Cykelstrom Bicycle Power Meter App enhanced the experience of being out on the bicycle with my family. I hope you can do the same.

Happy Riding,

Chuck