The Rotor retails for $2350, which puts it between the other two major crank based power meters, SRM and Quarq. Its major feature is that it’s essentially two power meters, with 4 strain gauges on each crank arm (SRM’s and Quarq’s have strain gauges in the spider). This is supposed to make it more accurate, as well as provide three additional pedal technique metrics: left/right balance, torque efficiency, and pedal smoothness.
Left/right balance is self explanatory. Torque efficiency measures how well you pull up on the upstroke (the cranks can tell which direction you’re deforming them, so they can tell you if you’re actually fighting yourself on the upstroke). Pedal smoothness is how ‘round’ your pedal stroke is, or how well you apply power in the dead spots.
You need to know where the cranks are for that data, so the Rotor has accelerometers to report its orientation. The accelerometers also provide cadence data – gone are the SRM/Quarq magnets. This may seem trivial but Mark says he spends a lot of time fine tuning magnet position for clients so their SRM’s and Quarq’s work properly.
Each crank arm has its own set of strain gauges and battery. The left ANT+ pod transmits to the right pod, which then sends data to the head unit.
The spider has two sets of holes so users of Rotor Rings can fine tune their orientation. Additionally the mounting holes in the rings are offset so that turning them 180 degrees gives you another half notch adjustment.
Here it is with rings mounted. Note the offset in the mounting hole options.
And here it is with the SRM that came off Chad’s bike, which doesn’t have the micro adjust spider.
Mark requested (demanded?) an action shot.
Here’s Garmin’s forward mount. The locking mechanism can rotate 90 degrees if you prefer your data in landscape.
And there’s the money shot on the new Garmin 810! Mark hand cranked out 22 mighty watts for a perfect 100% – 0% imbalance! I’m not sure if Garmin’s firmware supports torque efficiency or pedal smoothness yet, we’ll check back with Chad later after he gets a chance to ride it. The 810’s big new feature is its ability to pair with a smartphone via Bluetooth and then stream your data live. Check it out in this slick video with the Garmin team.
Here’s one of Chad’s ride files, see his comment below.