Not available for online purchase
The Stages M9000 Race version is built from two expertly forged pieces that are bonded together, with a reduced Q-factor of 156mm. XTR Race is available in 170mm and 175mm configurations. The Shimano XTR M9000 Stages Power meter replaces Shimano M9000 model left crank arm. Add power to existing cranksets, by selecting the crank length of your existing crank arm, as well as the matching crank model to account for a differences in the arms' offset.
Stages measure power with strain gauges that measure force in kilograms and converting it to power via simple physics equations. The major difference between Stages Power and the competition, however, is that Stages measures force on the left crank arm. In turn they measure power at the crank’s spider. Measuring power at the left arm requires one assumption — that your left and right legs have a balanced power output. Thousands of miles of testing showed that power differential between legs has no significant influence on ride data and its value as a training tool. This assumption is the tenant to Stages' ability to keep the complexity and cost of their system lower, all the while providing power measurement with ±2% accuracy.
The Stages Power meter uses a custom strain gage array to measure power at the left arm. By measuring power here, Stages Power eliminates the complexity of filtering the power data from chain torques and the multiple vectors associated with spider based units or efficiency losses through the drivetrain. This measurement then derives total power using an algorithm that effectively doubles a rider’s left-measured power.