Month: July 2022

Mountain Bike Power Meter – Kettle Moraine State Forest Northern Unit – New Fane, Wisconsin

Chuck

Cykelstrom is being used as a mountain bike power meter app in this ride demonstration.

Mountain Bike Power Meter App Accuracy For This Ride

The best accuracy for this ride is highlighted in bold.

SensorsCrank Power Meter (Watts avg.)Cykelstrom (Watts avg.)Difference (Watts)Margin of Error (Watts)
External Speed and Cadence128.11187.4759.35+/- 7.04
GPS Speed and External Cadence128.11145.7017.59+/- 5.64
External Speed Only129.25213.3384.08+/- 11.55
GPS Speed Only129.25162.4133.16+/- 6.27
Table created using Bland-Altman Analysis using a 4iiii Precision Pro single sided crank power meter as the standard with 95% confidence level.

Discussion Of The Mountain Bike Power Meter App’s Ride Results

Mountain biking presents more challenges in calculating power estimates of the rider on rough surfaces. Rapid changes in grade, roots, rocks, and direction, are challenges that do not exist when road biking. These challenges make estimating the cyclist’s power very difficult.

To address these challenges, I have introduced a new feature in the Cykelstrom Bicycle Power Meter App called “Mountain Bike Mode.” The new feature tunes the power estimate algorithm to more closely approximate the results of the single sided crank mountain bike power meter. Mountain bike mode is chosen under “Settings” in the Cykelstrom App. To learn how to change settings please visit Customizing Cykelstrom Through Settings.

Highlighted in bold, the table shows that when using the GPS with an external cadence sensor presents results which are closest to the crank power meter. To learn how to set up a cadence sensor in Cykelstrom please visit Adding Bluetooth Sensors to Cykelstrom.

Keep in mind that the forest canopy could be dense enough to block GPS reception, and in that case the addition of a speed sensor is suggested. For reasons which I am still investigating, I am finding that speed sensors when used in in rough terrain seem to overestimate the speed of the cyclist. I am experimenting with different technologies to try and determine why this is so. Accelerometer based speed sensors and magnet base speed sensor appear to agree with each other, but not agree with GPS speed. Calculating power estimates when using GPS speed agree more with the crank based power meter. So the saga continues and I will publish my thoughts as my ride testing continues.

Do you have any thoughts about this issue? If so please send an E-mail to: developer@cykestrom.com

Strava Activity

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Elapsed Time Moving Time Distance Average Speed Max Speed Elevation Gain Calories Burned
00:37:37
hours
00:37:37
hours
5.69
mi.
9.07
mph
17.05
mph
306.43
ft.
536
kcal

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The Cykelstrom Mountain Bike Power Meter App Is Only Available On Google Play

bicycle power meter app download button
Cykelstrom Bicycle Power Meter App Download
cykelstrom scan QR code
Scan to go to Cykelstrom on Google Play

Cycling Power Meter – Cykelstrom App Demonstration Ride West of Oshkosh, Wisconsin – June 21st, 2022

Chuck

This video demonstrates the Cykelstrom Cycling Power Meter App for Android smartphones while riding on rural country roads in northeastern Wisconsin.

Accuracy For This Ride

The best accuracy for this ride is highlighted in bold.

SensorsCrank Power Meter (Watts avg.)Cykelstrom (Watts avg.)Difference (Watts)Margin of Error (Watts)
External Speed and Cadence134.59140.936.34+/- 1.57
GPS Speed and Cadence134.59137.252.66+/- 1.53
External Speed Only135.01148.9813.97+/- 1.74
GPS Speed Only135.01145.0510.04+/- 1.69
Table created using Bland-Altman Analysis using a 4iiii Precision Pro dual sided crank power meter as the standard with 95% confidence level.

Discussion Of This Ride’s Results

I am pleased with the results of this ride as it shows that the Cykelstrom Cycling Power Meter App is giving me consistent results when riding the same course repeatedly. Cykelstrom displays the best results when paired with an external cadence sensor. To learn how to configure a cadence or other sensors with Cykelstrom visit Adding Bluetooth Sensors to Cykelstrom.

Cycling Power Meter App Uses Smartphone Sensors

Most smartphones have sensors that measure motion. The sensor combination is called an inertial measurement unit or IMU. The IMU is composed of accelerometers and a gyroscope that provides information about the smartphone’s orientation relative to the Earth’s surface. In addition to the IMU, most smartphones have a magnetometer and global positioning system. The magnetometer provides compass like direction information. The global positioning system provides provides location, direction, and speed information. The smartphone may also have a data link to a weather information service. With information from the sensors, GPS, data link, some clever math and empirical evidence Cykelstrom estimates how much power the cyclist generates.

Strava Activity

Click on the map to visit this activity in Strava. Follow me on Strava to see more Cykelstrom Activities that were automatically uploaded. To learn how to configure Cykelstrom to automatically upload your rides visit Upload Your Ride Data to Strava.

Elapsed Time Moving Time Distance Average Speed Max Speed Elevation Gain Calories Burned
01:45:15
hours
01:43:04
hours
25.30
mi.
14.73
mph
24.54
mph
436.68
ft.
1,049
kcal
Another hot day!

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The Cykelstrom Cycling Power Meter App Is Only Available On Google Play

bicycle power meter app download button
Cykelstrom Bicycle Power Meter App Download
cykelstrom scan QR code
Scan to go to Cykelstrom on Google Play

Power Meter – Cykelstrom Bicycle Power Meter App – West of Oshkosh, Wisconsin – June 24th, 2022

Chuck

The power meter capabilities of Cykelstrom help the cyclist understand where power is going during their ride. Cykelstrom calculates and displays the components of power due to wind, grade and rolling resistance.

Power Meter App Accuracy For This Ride

The best accuracy for this ride is highlighted in bold.

SensorsCrank Power Meter (Watts avg.)Cykelstrom (Watts avg.)Difference (Watts)Margin of Error (Watts)
External Speed and Cadence140.16148.358.19+/- 1.48
GPS Speed and External Cadence140.16145.054.89+/- 1.41
External Speed Only140.64156.308.19+/- 1.65
GPS Speed Only140.64152.8612.22+/- 1.56
Table created using Bland-Altman Analysis using a 4iiii Precision Pro dual sided crank power meter as the standard with 95% confidence level.

Discussion Of This Ride’s Results

I developed Cykelstrom for those who wanted to see their power data while riding, but did not have the resources to purchase an actual power meter. The accuracy of an app running on a smartphone is not better than an actual power meter, however we keep improving to get as close as possible. Every now and then a ride’s results just gets me excited to see that it is possible to be very close to an actual power meter’s performance. It is clear that for best performance, using the Cykelstrom in conjunction with an external cadence sensor provides the best results.

The cost of a cadence sensor is an order of one or two magnitudes cheaper than a power meter. Cykelstrom when set up and calibrated properly can give acceptable results and enhance the cyclist’s ride experience. To learn how to set up Cykelstrom please visit Setting Cykelstrom Up For The First Time. To learn how to add a cadence sensor or any Bluetooth sensor visit Adding Bluetooth Sensors to Cykelstrom.

Strava Activity

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Elapsed Time Moving Time Distance Average Speed Max Speed Elevation Gain Calories Burned
01:40:43
hours
01:37:35
hours
25.30
mi.
15.56
mph
23.87
mph
437.01
ft.
1,054
kcal

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The Cykelstrom Power Meter App Is Only Available On Google Play

bicycle power meter app download button
Cykelstrom Bicycle Power Meter App Download
cykelstrom scan QR code
Scan to go to Cykelstrom on Google Play

Bicycle Computer – Cykelstrom Bicycle Power Meter App – West of Oshkosh, Wisconsin – June 20th, 2022

Chuck

Cykelstrom is being demonstrated as a bicycle computer by displaying cycling performance information during this test ride.

Accuracy For This Ride

The best accuracy for this ride is highlighted in bold.

SensorsCrank Power Meter
(Watts avg.)		Cykelstrom (Watts avg.)Difference (Watts)Margin of Error (Watts)
GPS Speed and External Cadence132.69154.1021.42+/- 1.39
GPS Speed Only132.21164.0830.87+/- 1.56
Table created using Bland-Altman Analysis using a 4iiii Precision Pro dual sided crank power meter as the standard with 95% confidence level.

Discussion Of This Ride’s Results

The accuracy of this ride was not ideal, relative to the results of other similar rides. I suspect that I did not not calibrate the crank power meter correctly or I used the wrong side of the dual sided power meter for power information. This highlights the importance of selecting the correct sensor when collecting data. In my case, the dual sided power meter sends the correct power data through the left sensor, however you can connect to the right side power sensor and get a power reading, however that reading is for the right side only. If you are using a dual sided power meter, make sure you connect to the side that reports the combined power total. This is usually the left sensor side. If you are using a single sided power sensor this is not an issue.

Bicycle Computer Functions

I designed Cykelstrom to be a simple bicycle computer in addition to its ability to estimate the cyclists power. Cykelstrom displays and records the cyclists speed, heart rate, cadence, distance traveled, heading and many others. To learn how to use these functions and more see Using Cykelstrom On Your Ride in the Quick Start Guide.

Strava Activity

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Elapsed Time Moving Time Distance Average Speed Max Speed Elevation Gain Calories Burned
01:44:50
hours
01:44:03
hours
24.70
mi.
14.24
mph
22.51
mph
437.34
ft.
1,151
kcal
Super hot day with temperatures in the mid 90's

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The Cykelstrom Bicycle Computer App Is Only Available On Google Play

bicycle power meter app download button
Cykelstrom Bicycle Power Meter App Download
cykelstrom scan QR code
Scan to go to Cykelstrom on Google Play