Rotor's new 2INpower meter was launched in Spain recently and promises doubled riding data to strengthen riders' knowledge of their own performance

Pronounced 'twin-power' by its creators, 2INpower expands upon Rotor's existing INpower meter by combining driveside power measurement to the original INpower's non-driveside axle measurement. The result is incredibly accurate data for each leg along with the robust performance that's become INpower's calling card. Those performance credentials are already proven with 2INpower meters, which have already covered over 250,000 miles of professional riding from the Team Dimension Data and Cervelo-Bigla squads.

How 2INpower works

2INpower adds a pair of strain gauges to either side of the driveside crankarm. Positioned in opposition, as one set stretches under load the other compresses to compensate, accurately measuring flexion in the crankarm. The system's main electronics and non-driveside strain gauges remain in the axle, measuring only the torsion from the left leg.

These two sides of the meter work independently. Power from the right leg detected in the crankarm's gauges as it passes onto the drivetrain while the left leg's power has to pass through the axle before contributing to driving the bike forward.

Whereas the axle of INpower is connected to the non-driveside, with 2INpower it's connected to the driveside arm. This allows completely clean and reliable wired electronic communication between both sides of the power meter with no slave / master set-up as in the brand's previous generation of meters. The non-driveside arm is held in place with a simple DTT bolt.

Advanced metrics

Rotor continues to lead the industry when it comes to power fidelity. The collection of 500 data points per revolution via accelerometer – as opposed to the many designs that measure only one data point per revolution – gives exceptional accuracy even when used with Q-Rings.

This accurate measurement opens the door to advanced metrics that Rotor originally ushered in with its left-right power meter – including balance, pedal smoothness and torque effectiveness.

Pedal smoothness is your average power divided by maximum power per stroke – how big the peaks and troughs in your application of power to the cranks are.

Torque effectiveness is total power per revolution divided by positive torque (when you're pushing the pedal rather than pulling it up) to give a figure of how much negative torque there is in your stroke.

Added to true left-right leg balance, this big data opens up a whole world of information for performance coaches. Athletes' training loads can now be moderated based on left-right leg fatigue while coaches can also maintain a whole data set of each rider's leg power to refer to in the event of injury, enabling faster recovery times.

Transmission of all this data to your head unit is via ANT+ while Rotor has also added Bluetooth Smart for increased head unit compatibility, app-based firmware updates and mobile OCA testing. Bluetooth functionality is due before the end of 2016. Rotor is also updating its INpower user software to take advantage of 2INpower's added data potential.


Rather than INpower's replaceable AA battery, 2INpower uses a built-in battery that's completely waterproof and charges via magnetic USB connection. Simply rotate the rubberised cover and the cable snaps on, LED lights giving you charge information.

The Li-ion battery will take around 300 charges before deteriorating, with each charge giving around 250 hours of riding. Riding five hours every single day, that's 41 years of use.

Crank design

Made from aerospace grade 7015 aluminium, the 2INpower crankset is noticeably wider and more muscular looking than Rotor's other cranks. This design contributes to the power meter being a stiffer system as a whole than 3D+ while adding just 160g for all the power-measuring electronics. Crank lengths are the same as INpower – between 165 and 175mm.

Following feedback from riders who wanted their power meters to be more conspicuous, Rotor has added red anodised accent colours to the design. This is particularly striking on the end of crankarms, and should ensure that if a rider is going to spend on a power meter, their riding buddies will know about it!

Availability and pricing

2INpower will be available in the UK via Saddleback from May and costs £1,200.