Upgrading to that shiny new Dura-Ace 9100 groupset was a winter milestone that took your ride to the next level, and after spending some time with it you're starting to regret not adding a power meter to the setup to get the most out of those limited training hours. Let's be honest though, the reason you didn't get that fully matching, power-reading crankset in the first place is the wallet-crunching cost of a dual-leg, crank-based meter. But now, thanks to Stages Cycling and its Shimano Dura-Ace R9100 Single Leg Power Meter Crank Arm, you can keep that sleek 9100 aesthetic and add accurate power measurement for a fraction of the cost.
The crank arm itself is the same as the non-power Dura-Ace 9100 left arm on your bike right now, just with a Stages power meter affixed to its inner surface. Tucked inside this little pod, strain gauges and an accelerometer measure force and rotations to deliver power data to your head unit with a claimed accuracy of +/- 2%, which is in-line with other quality power meters on the market.
The meter also incorporates Stage's Active Temperature Compensation (ATC), which compensates for the natural expansion and contraction of the strain gauges by adjusting the readings depending on external temperature. ATC accounts for those temperature changes without requiring you to stop pedaling in order to zero the system. Overall, the power meter adds less than 20g to the crank, which is a tiny tradeoff for its ability to capture power information as it transfers from the pedals into the drivetrain.
A Dura-Ace 9100 left crankarm with power measuring capability
Measures power with an industry-standard +/-2% accuracy
Active Temperature Compensation accommodates changing conditions
Internal accelerometer covers cadence with no additional sensors
Wireless communication keeps use and maintenance simple
Pairs with Stages Power App for firmware updates and zero resets
200+ hour battery life with easily-changeable CR2032 coin cell battery
Stages Cycling brings power data into an affordable price range
Length: 165mm, 167.5mm, 170mm, 172.5mm, 175mm, 177.5mm, 180mm
Tool free battery replacement
Active temperature compensation
Accelerometer based cadence measurement
Wireless firmware upgrades