Since being introduced in 2013, Pioneer's crank arm power meters have become ubiquitous everywhere from T1 at a local triathlon to 86 podium appearances for the men and women of UnitedHealthcare Pro Cycling Team. Two years in, the technology is proven, but the huge metric gathering, data crunching capabilities that Pioneer built into it mean the entire system a Dual Leg Power Meter and Pioneer computer also comes with a huge price tag. The pros may need all of that extra information, but for a typical Cat 4 or a fitness focused recreationalist, popping for the whole system may be overkill at least initially. The new Shimano Dura Ace Single Leg Power Meter Crank Arm addresses these needs, providing a more affordable entrance to the world of Pioneer power metrics that leaves the door open for future upgrades. Upgrade path aside, the Single Leg Power Meter is an impressive piece of tech on its own, and since it broadcasts wirelessly with ANT, chances are good that it's already compatible with your current head unit or wearable. 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 system's Active Temperature Memory Adjustment feature 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 has a waterproof rating of IPX6 and IPX7, so it can handle inclement conditions as well as extreme temperatures. The system uses Shimano's top tier Dura Ace crank arm as a platform, matching the meter's unmatched...