HIGH PRESSURE TYRES GIVE YOU MORE SPEED FOR LESS EFFORT…

Don’t fall foul of piling on the pressure for an easy speed fix

“Highly pressurised tyres work against you for several reasons. The lower air volume and harder tyres transmit more vibration”

Despite the fact that we probably all know better, few cyclists can break the habit of pumping their tyres to iron-hard consistency. Rob

Kitching has crunched the numbers. “We should go back a step and say that ‘the tyres producing the lowest coefficient of rolling resistance (Crr) are the ones which give you more speed for less effort.’ Crr is a number that expresses the amount of power required just to keep the tyres rolling, relative to your speed and weight. Several factors determine this figure including the flexibility of the tyre casing, flexibility of any inner tube, pressure in the tyres, and the road surface. Current thinking is that there is a sweet spot pressure above which Crr actually increases, in other words extremely high pressures may be counterproductive. Identifying the tyres with the lowest Crr depends on so many variables, so we would always recommend that riders who care deeply about every watt of efficiency carry out field tests using power meter data. We have a tool that makes this easier at fastaerolab.com.”

Dr Cheung adds, “Highly pressurised tyres work against you on the road for several reasons. The lower air volume and harder tyres transmit more vibration from the road to your body, causing more fatigue. Harder tyres also bounce around more, and you can’t transmit power to the road if your tyres aren’t touching it.”