Each power meter that leaves our production undergoes a measurement quality test in the form of a test verifying the correctness of the indications in various power and cadence ranges. The tests include trial runs on a SMART trainer with electromagnetic resistance and an additionally installed third-party single-sided power meter.
When comparing power readings between a trainer and a power meter, the following factors should be taken into account:
- Power measurement is unilateral (left leg power x2), while the trainer can be treated as a bilateral measurement. If there is an imbalance between the right and left leg (most users do), the reported power value will be different.
- The measurement is made on the bicycle drive element, so the moments responsible for resisting resistance and gravity are measured (in short, the moments responsible for propelling the cyclist on the bicycle). However, in the trainer, the resistance generated at the end of the kinematic chain of the bicycle’s drive system is measured. Moving elements in the system may affect both indications through phenomena such as friction, play and selection, etc.
- Trainers generate constant resistance throughout the entire crank cycle. However, the power generated by the legs is highly variable during this cycle. In this way, there is not only a difference between riding “outdoors” and riding on a trainer, but also a different average power can be determined depending on the adopted computational algorithms.
- Taking the above factors into account, it is possible to get different readings on both devices and both remain correct.
Before performing comparative rides, perform:
zero-offset calibration of the Inpeak meter,
spin-down of the trainer,
If you want to bring both readings closer together, you can use the “scale” option in the “INPEAK Manager” mobile application (you should first check in this application whether the meter has the current software version). Using the slider you can compensate for the imbalance between the legs by +/- 5%.
If, in the light of this information, the operation of the INPEAK meter is still questionable, please contact us. Remember to provide information: SN number of the meter, received calibration value, .fit files from a simultaneous trip on both devices enabling comparison of readings.
