Is Your Cycling Computer Lying About Your Power Data?
Sticky watts phenomenon causes cycling computers to misrecord power output during coasting intervals.
1The Power Recording Discrepancy
Cyclists often assume their power meters provide the absolute truth, but the recording device matters significantly. When comparing different cycling computers paired to the same power meter, data inconsistencies frequently emerge. These discrepancies can be frustrating for athletes who rely on precise metrics to track their training progress and physical performance.
2Understanding Sticky Watts
Sticky watts occur when a cycling computer continues recording a power value for several seconds after the rider stops pedaling. Instead of dropping to zero, the device holds the last recorded wattage in the file. This creates artificial data points that inflate the total work performed during a ride session.
3Impact on Training Data
These extra watts accumulate during rides with frequent corners, descents, or stop signs where coasting is common. If a rider performs a high-intensity effort followed by coasting, the computer may hold a high wattage value. This skews the overall average power, making it difficult to compare training efforts across different days.
4Evidence from Field Testing
Testing revealed that the COROS DURA 2 consistently recorded higher power than Garmin units during identical rides. In one specific interval, the DURA 2 held 565 watts for four seconds while other devices correctly recorded zero. Over a 98-minute ride, this resulted in a significant average power difference between the devices.
5Software Versus Hardware Issues
This phenomenon is distinct from settings that exclude zeros when calculating average power. Sticky watts affect the raw data recorded in the ride file itself, meaning the error persists during post-ride analysis. While some manufacturers improve recording accuracy through firmware updates, the issue remains a persistent challenge for modern cycling computers.
6How to Verify Accuracy
Riders can identify this issue by recording the same ride on two different cycling computers paired to one power meter. Alternatively, users can examine their own ride files by zooming into sprint sections. If one device shows a flat line while the other drops to zero, the computer is likely recording sticky watts.
7Context of Precision Tools
Modern cycling computers are marketed as high-end precision training tools, often commanding premium prices. Because accurate data recording is central to their value proposition, users expect reliable performance. When devices fail to record zero power during coasting, it undermines the integrity of the training data used by coaches and athletes.
8Implications for Serious Athletes
For casual riders, a few extra watts may not change their training outcome. However, for athletes working with coaches, these inconsistencies complicate performance tracking and ride comparison. As technology advances, ensuring that hardware accurately reflects human effort remains a critical requirement for maintaining the validity of digital cycling training platforms.
Original article: Bicycling — Is Your Cycling Computer Lying About Your Power Data?