Clincher tyre rolling resistance performance in track cycling

TUBULAR TRACK RACING TYRES 

Vittoria Pista Speed 23mm

Vittoria Pista Oro 23mm

Continental Sonderklasse 23mm

Continental Olympic 19mm

Continental Tempo 22mm

Veloflex Record 23mm

Veloflex Record 25mm

Dugast Pista Latex Silk 22mm

CLINCHER TRACK RACING TYRES

Vittoria Pista Oro 23mm

Veloflex Record 23mm

Continental GP5000 TT 25mm

Vittoria Corsa Speed 23mm

Vittoria Corsa Pro Speed 24mm

Vittoria Pista Control 23mm

In order to test rolling resistance, we swapped between the tyres as a rider rode a bike on rollers, measuring power output and speed, as well as atmospheric conditions and bike/rider weight, repeated over a number of days testing. This allows us to calculate what is known as the Coefficient of Rolling Resistance (or "Crr"), which can be used to model the power output required to travel on a normal road. A lower Crr is better - in that it requires less power to travel at the same speed.

All tubular tyres were fitted to a tubular aluminium rim using Continental rim cement in multiple cured layers, and inflated to 150psi.

Clincher/TLR tyres were all mounted using a Vittoria latex inner tube. In previous testing we have found no difference between tubeless sealant of ~30ml and a latex tube, and we do not recommend using tubeless sealant in a track scenario.

Some clincher tyres were inflated beyond manufacturer stated maximum pressure - this is for information only and we do not recommend inflating tyres beyond their stated maximum pressure.

In this test, we found that the fastest tubular tyre (at 150psi), a Dugast Pista Latex Silk 22mm was nearly identical to the fastest clincher tyre, a Vittoria Pista Oro 23mm when inflated to 130psi. This is however beyond the max stated pressure for the Pista Oro, and the next fastest clincher tyre was a Veloflex Record 23mm at 130psi, 0.6w slower than the Dugast for a pair of wheels at 55kph.

A rolling resistance change of 0.6w is worth around 25m over an hour record at 55kph.

The tubular tyres tested, when inflated  to 150psi were much narrower than their clincher/TLR equivalents. For example the Dugast Pista Latex Silk 22mm was nearly 4mm narrower than the Vittoria Pista Oro 23mm clincher at 130psi.

Because of the small differences between tyres at these pressures, it is critical to understand the aerodynamic performance of a chosen wheel/tyre combination, as the aerodynamic contribution to resistive forces can outweight small changes in Crr.

In this test we have found that modern clincher tyres, when inflated to high pressures, return very similar Crr values to tubulars that are also inflated to high pressures.

The correct pressure for a given scenario will change - on exceptionally smooth velodromes higher pressures are able to be used, in excess of the 150psi tubular pressure used in this test, but this will vary depending on track surface.

Because of the importance of aerodynamics at high track speeds and the closeness of Crr between tubulars and clinchers, the aero performance of wheels should be foremost when deciding on equipment choice, with tyre type secondary.