Less resistance, more speed

Michelin are claiming the reduced rolling resistance of the new Power Competition tyre can save a rider 10 watts at 35km/h – enough to knock 1:04 minutes off the ascent of Alpe d’Huez or adding a further 776m to the hour record, according to the French tyre manufacturer.

That 10-watt figure is specific to a rider and bike package weighing 70kg, however. It would be different for larger, heavier riders on different bikes but Michelin are convinced the Power Competition can still deliver a significant improvement nevertheless. And to prove it, Pierre-Yves Formagne of Michelin’s bike division had come up with a simple two-ride test protocol.

Peaks and troughs

The weather decided to throw a spanner in the works, however. Despite the bright, clear skies, chilly spring winds were howling across the test track. Each ride was spent alternately battling into a headwind while attempting to keep the power from spiking out of the target range before turning into a tailwind and pedalling frantically to try and stop the power falling through the floor. Given the conditions, the test procedure quickly went out of the window, as the numbers being generating could not be used to make a reliable comparison.

Fortunately, there was a back-up plan. The machine used to test rolling resistance during the development of the tyre had been wheeled out to the marquee by the dry-handling test track and a demo was carried out on that.

First a wheel with a Pro4 tyre, Michelin’s out-going model, was mounted into the rig. The Pro4 shod wheel sits on a spinning drum that’s driven up to 44km/h and after it settles at that speed for a minute or two, the drum is disconnected from the motor, leaving the wheel to spin down to a standstill. The only thing slowing the drum down is the friction generated by the tyre so the distance covered in between the motor being disconnected and the wheel coming to a complete stop provides an indication of the tyre’s rolling resistance – the greater the distance, the less the resistance the tyre has.

The Pro4 tyre covered 951m in the course of slowing down to zero from 44km/h. The Power Competition, however, covered a little over 1,300m before coming to a standstill.