Torque X Angular Velocity: PowerTap P2 Pedal
From Issue 85
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The pedal is not the “best” or “easiest” place to measure power. The crank, the spider, the bottom bracket or the hub can all lay claim to a “better” place to measure power. But pedals—specifically PowerTap pedals—have won our hearts as simply the most “convenient” way to measure power.
PELOTON
If you can swap pedals, you can install PowerTap’s pedal power meter. You can switch them from your road, TT or even gravel bike. Renting a bike on the road? Your power meter’s in your luggage and will take less time to install than adjusting the saddle. Even your GPS, going from bike to bike, is looking for the same power meter.
Our appreciation for the power pedal was born two years ago during a trip to Belgium. Riding borrowed bikes, we set them up with the P1, PowerTap’s original power pedal, and rode—no extra pods, no critical alignment issues. We rode the cobbled climbs in freezing rain and gale-force winds, and then abandoned our bikes to the elements as we slurped up Flemish beef stew. The P1s faithfully captured our wattage, pedal stroke for pedal stroke. We were extremely impressed with the power numbers—at least the meter’s ability to produce them accurately and consistently in the harshest of conditions. The numbers themselves left a bit to be desired from both watts-per-kilo and peak-wattage standpoints…but we digress.
Measuring power in watts is just “torque x angular velocity.” Simple right? Not so fast. Measuring the angular velocity of a hub or chainring is easy, but to get the right torque number many forces, including rider weight and side loading, need to be canceled out. With the pedal free to move around the spindle and cantilevered from the crank, measuring both angular velocity and torque presented significant challenges. PowerTap actually measures the angle of the pedal on the spindle relative to the crank arm, 100 times a second, with some serious math. It’s this little trick that allows you to install PowerTap pedals like any regular pedal, as well as get advanced metrics to dissect your pedal stroke like never before.
Now PowerTap’s second-generation power pedal, the P2, is here; and it’s the culmination of many small tweaks to the P1 adding up to an entirely new pedal. Battery life is improved by 20 percent thanks to the removal of a redundant analog-to-digital to converter, weight has been removed by increased tooling of the body, sealing has been improved and the claw profile has been changed to drop more weight and improve compatibility with more shoes. PowerTap’s P2 pedal is simply the easiest way to get consistent and accurate power numbers with the least hassle and most convenient package available. Plus, they are silver, which is just cool. 398g per pair w/batteries; $900; quarq.com
This review originally appeared in issue 85.