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Road tubeless liners and rolling resistance

25 November 2020
In previous tests we have shown the importance of rolling resistance on cycling performance. A tyre with a high rolling resistance will require more power to travel at the same speed, whilst a low rolling resistance tyre requires less power.

In this experiment we explored how adding a tubeless liner to a Continental GP5000 tubeless tyre affected the rolling resistance.

The goal of this test was to evaluate the rolling resistance impact of using a tubeless liner in a Continental GP5000 tubeless tyre.

For this test we used the popular Continental GP5000 TL (tubeless) tyre in 25mm. This tyre has both good rolling resistance & also aerodynamic properties.


It was mounted on a shallow section aluminium rim with an internal width of 19.6mm and external width of 24.7mm.


LINER

The liner was a Tubolight Road, designed for 23-28mm road tyres. This weighed 11 grams on our scales. 


SEALANT

We used 30ml of Zefal sealant, two layers of standard tubeless rim tape and a standard tubeless valve. During the development of our AEOX tubeless wheel range we found Zefal sealant to perform well and seal effectively.

In order to test rolling resistance 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. Tyres had a standardised inflation of 90psi.

The results of the tubeless liner testing can be seen below.


There was a 4.4% increase in rolling resistance with a tubeless liner, but this penalty was relatively small (similar to what you would experience by overfilling the tyre with tubeless sealant as we have previously found in our tubeless sealant test)


At 45kph, this is a penalty of 1.2w for a pair of wheels on the flat for a Tubolight insert in a Continental GP5000 TL 25mm.

In this test we found that using a tubeless liner with a Continental GP5000 TL 25mm tyre resulted in <5% increase in rolling resistance, or just >1w for a pair of wheels at 45kph.


The liner was extremely light at just 11g, and so could be an option for those looking for increased safety in the event of a tubeless blowout.


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