Rotor

INpower 3D30 Power Meter Crank Arms

Having a power meter on your bike isn't just about "performance" gains. Tracking data can be its own reward, and it opens up myriad possibilities for using smart trainers to turn indoor winter miles into something bearable, if not actually enjoyable. But the obvious benefits of Rotor's INpower 3D30 Power Meter Crank Arms are that come race day, when all those winter trainer miles, spring base miles, hill repeats, and intervals are behind you, you'll be able to precisely meter your effort in order to achieve your best possible result. Of course, things don't always go as planned in races, but the INpower 3D30 meter does help smooth out some of the potential issues. In fact, the system was tested by guys like Rui Costa when he was riding for Lampre. (Which, for the record, Lampre's kits remain some of our favorite of all time.)

The reason guys like Rui Costa rode INpower is, of course, the internals. Instead of the dual-leg, eight-gauge approach of the 2INpower model, the INpower meter uses four gauges to measure power coming through the left crank arm only. The strain gauges themselves live in the spindle. This provides more protection against the elements (be they rain, snow, or tarmac encountered during the occasional user error), and it also helps to tidy up the crank's silhouette by eliminating bulbous protrusions at the crank arm/chainring interface—of course, the grooved crank arms and (should you run them) Rotor's iconoclastic chainrings will still stand out.

As with other power meter cranksets, the INpower's four strain gauges are all spindle-bound and it's equipped with an accelerometer to read cadence; unlike other meters, Rotor's design measures cadence over 500 times per pedal stroke. While the benefits of mapping minute changes in cadence over each leg's power production are immediately obvious to any data obsessive, the potential is magnified exponentially when paired with Rotor's Q-Ring system. It helps you chart the most efficient Q-Ring orientation possible to capitalize on the strengths of your pedal stroke while mitigating the weaknesses. The crank arms work just fine with traditional round rings, but adding Rotor's Q-Rings takes full advantage of the system's potential.

The INpower transmits data via ANT+ Smart protocols, so chances are good that it's already compatible with whatever head unit you're running; however, it's a bit more limited on the bottom bracket front. The INpower 3D30 has a 30mm spindle, so it may take some adapting to adapt it to your shell, but it's compatible with English and Italian threaded, BB86, BBRight, BB386EVO, and—of course—BB30 and PF30 bottom bracket shells. The unit's 300-hour ride time relies on AA batteries, so re-upping is never an issue. Rotor also provides a seamless data upload and management interface by partnering with TrainingPeaks.