What is Calibration?
One of the best features of a smart trainer is its ability to provide power numbers. And when it comes to power, nothing is more important than accuracy.
With a smart trainer, the heart of power accuracy lies in calibration. This calibration process is especially important with smart trainers that have a tire-to-roller interface, also known as a wheel-on trainer. The CycleOps Magnus is an example of this type of smart trainer.
Since each bike setup is different, each bike needs to be calibrated with a smart wheel-on trainer to ensure the best possible accuracy. This is because no two bike setups are the same, as each uses different tires, rims and recommended tire pressures, all of which play a role in dictating the rolling resistance measured by the trainer.
It’s this varied rolling resistance that the roll-down calibration is measuring and accounting for when calculating power readings or wattage. Since rolling resistance can change from session to session, or even within the same ride, we recommend performing a calibration as frequently as you wish to keep your power numbers as accurate as possible.
You may notice that this recommended calibration protocol is for wheel-on smart trainers only. This is because direct drive smart trainers do not need to be calibrated as often as wheel-on trainers, as there is no tire-to-roller interface. The direct drive design reduces the variability in rolling resistance from ride to ride. While you can still calibrate direct drive trainers as often as you would like, often a weekly or even monthly calibration is sufficient.
When it comes to calibrating your wheel-on smart bike trainer, there are two ways to go about this important process.