If a French start-up has its way, cyclists will no longer have to waste power.

The better trained a cyclist is, the more power they can transfer to the pedals. The better amateur cyclists therefore like to boast about the wattage they can generate. But what does that power figure actually tell us? Not nearly everything. The majority of the energy the cyclist generates is never converted into speed. That energy is lost due to air and rolling resistance.

To better understand and subsequently reduce these losses, cyclists have always had to rely on costly wind tunnel testing. A French start-up has now come up with an alternative: Wasted Watts. This tracker, not much bigger than a cycle computer, comes in two models: one is mounted on the handlebars and the other on the rear of the seat post. Together, they measure airspeed, direction of travel, temperature, air pressure and gradient whilst cycling.

Combined with data from a power meter, GPS and speedometer, the accompanying software calculates how much power is lost due to air and rolling resistance, as well as changes in elevation. According to the makers, the device effectively transforms the public highway into a personal wind tunnel, allowing different riding positions, helmets, wheels or clothing to be compared under realistic conditions. Wasted Watts is therefore aimed not only at keen amateurs, who can see in real time via their cycle computer where and how they are wasting power, but also at bicycle manufacturers, bike fitters and aerodynamics specialists.

Whether the tracker matches the accuracy of a real wind tunnel remains to be seen in practice, although the manufacturer claims the margin of error is below 2 per cent.

However, the start-up is capitalising on a clear trend in which aerodynamics is no longer the exclusive domain of professional cyclists. For those who spend a lot of euros on an aero helmet or carbon frame, a better understanding of the efficiency of their own aerodynamics can yield at least as much benefit as squeezing a few extra watts out of their legs.

That said, the Wasted Wattstracker is a substantial investment. When the system goes on sale, the price is expected to be around 2,500 euros.