The Rotor Power was unveiled as a prototype at Eurobike in August 2012 but it’s taken some time since then for the system to make it to market. The wait is over, however, and the Spanish firm’s watt recorder has made its way on to the bikes of WorldTour team Lampre-Merida this season.

Like Garmin Vector, it’s two meter meters in one, with strain gauges located in both the left and right Rotor 3D+ MAS crank arms, adding a claimed 30g to the power-less crankset.

That allows Rotor to make an impressive spread of data available, including left/right leg power output, torque efficiency – a reading which shows the positive and negative torque per leg, effectively showing the extent to which your legs are working against each other – and pedalling smoothness. Rotor also claim the Power system is accurate to +/- two per cent and that it’s immune to temperature variation.

Pros: Left/right measurement, unique data, light
Cons: Limited to Rotor cranks, expensive at £1,450
Website: Rotor