If you happen to be running Shimano's flagship drivetrain and plan on dabbling with power, you might want to have a look at another Japanese giant and check out the Dura-Ace R9100 Bluetooth Single Leg Power Meter Crank Arm from Pioneer. As such, you'll keep the aesthetic and performance of your Dura-Ace group in check while gaining the ability to quantify power so you can train and race with more efficiency. Whether you hire a coach or you are your own, having a powermeter lets you track your physical potential as you progress. The single-leg approach may not let you parse out the power production nuances of each leg individually, but it does provide a full number in order to chart your total output and if you really want to analyze your pedaling further, you can always add the driveside powermeter down the road for dual leg measurements. For most cyclists though, the single leg option is more than enough to get a leg up on their goals. The Single Leg Power Meter is an impressive piece of tech on its own, and since it broadcasts wirelessly with ANT+, and this newly updated version adds Bluetooth to the mix, chances are good that it's already compatible with your current head unit, watch, or phone. It measures pedaling force, direction, and overall efficiency by monitoring 12 points of rotation at 30-degree intervals across the pedal stroke. At each point, the deflection caused by radial and tangential forces on the crank arm is scanned 16 times to ensure a claimed +/-2% accuracy, the industry benchmark. Thanks to its Active Temperature Memory Adjustment feature, the power meter maintains that accuracy in temperatures ranging from 14 to 122 degrees Fahrenheit, so it stays on point even in extreme conditions. This eliminates the need to freewheel in the middle of a race in order to zero the system, a situation that can cost you precious momentum during a solo effort or make you lose your safe position near the front just as the race hits a climb. The unit also ha...