Zero offset calibration is the process in which the zero offset value is updated for the power meter. This is an important process as it ensures the power meter has an up to date value for 0 (or no load on the power meter). Depending on the head unit used, this process may be referred to as calibration or zero reset. 

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How do I calibrate my Stages Power Meter?

I can't get my power meter to calibrate

Zero offset calibration

The act of calibrating the zero offset causes the power meter to measure the value at zero load and then records this value as the baseline for power measurement. Loads applied while pedaling will then be measured as torque and used by the sensor to determine power in watts.  Anytime the power meter is installed or removed from the bike, the torque applied by the crank arm bolts can also have an effect on the zero value, which can be easily accounted for by resetting the zero value on the power meter. To ensure maximum accuracy, we recommend performing a zero reset (or “calibrate”) before each ride.

When paired to a compatible head unit, the power meter and head unit are in two-way communication and the head unit is able to send a command to the power meter to perform a zero reset and in some cases, the resulting zero reset value(s) will be sent back from the power meter to the display unit and be shown on the screen. Please note the displayed zero reset value(s) will NOT be zero, but rather a number that corresponds to the measurement taken by the sensor. The head unit will also indicate if the procedure succeeded or failed. This process may be referred to as zero reset, calibration, or zero offset depending on the head unit manufacturer. For all Stages Power meters, the crank arms must be in the vertical position with no weight on the pedals in order to properly perform a zero reset.