Investigating the Deception in Bicycle Tyre Tests: A Fresh Look at Rolling Resistance and Drum Support
In the world of cycling, the quest for developing the fastest tyre is a never-ending pursuit, centred around a metric called rolling resistance. While the roller drum test has been the standard method for measuring this crucial factor for decades, alternative testing methods are emerging to provide more accurate and comprehensive results.
One such alternative is the On-Vehicle Coast-Down Testing. This approach measures rolling resistance by recording the deceleration of a test vehicle as it coasts to a stop on a given surface. It captures actual rolling resistance under real-world operational conditions on both paved and unpaved roads by implicitly including tire-road interactions, aerodynamics, and drivetrain losses. This method is widely used alongside standard laboratory tests for tires and vehicles.
Another laboratory-based alternative is the Wheel Tracking Test. Primarily used for asphalt, these tests simulate traffic effects on pavement structures by measuring the deformation and rutting resistance caused by repetitive loading. While primarily focused on evaluating rutting susceptibility, wheel tracking tests indirectly relate to rolling resistance by assessing how pavement deformation influences energy dissipation during wheel passage.
Other laboratory asphalt performance tests, such as ductility and material property measurements, help evaluate the asphalt mixtures' resilience and behaviour under stress. Though not direct rolling resistance measurements, they contribute to understanding material factors that affect rolling resistance.
Alternatives to roller drum testing for measuring rolling resistance on unpaved roads include on-vehicle coast-down methods and wheel tracking tests that simulate traffic-induced deformation effects on pavement materials.
The Chung Method, also known as Virtual Elevation Testing, is an alternative to drum testing for predicting the coefficient of rolling resistance in field testing. It involves riding a short, stop-free course several times at a variety of power outputs with a power meter and accurate speed and altitude gain measurements. While it can be used for aerodynamic improvements, the results may be rider and conditions specific.
The steel drum test, despite being widely used in the industry, does not reflect another major aspect of rolling resistance, called impedance or suspension losses, which are particularly relevant on actual paved roads. Even when discerning how tyres perform relative to one another, drum testing has limitations.
Bringing an outdoor surface indoors for testing variables would be an ideal scenario, but it would take immense resources to realize. This is particularly true for gravel races, where the inconsistent surfaces make it difficult for riders to decide which part of the course to prioritize their equipment for.
In summary, coast-down testing on actual roads and wheel tracking/tests simulating traffic loading in the lab are practical alternatives or complements to roller drum testing for rolling resistance measurement on varied road surfaces. These methods provide a more comprehensive understanding of rolling resistance, bridging the gap between laboratory tests and real-world conditions.
[1] "Alternatives to Roller Drum Testing for Measuring Rolling Resistance on Paved and Unpaved Roads" (Source) [2] "On-Vehicle Coast-Down Testing for Rolling Resistance Measurement" (Source) [3] "Advances in Tire Research for Reducing Rolling Resistance" (Source)
[1] The On-Vehicle Coast-Down Testing, an alternative method to the roller drum test, measures rolling resistance under real-world operational conditions and captures tire-road interactions, aerodynamics, and drivetrain losses.
[2] Complementing laboratory-based tests like the Wheel Tracking Test, science and technology have led to the emergence of newer methods that aim to provide more accurate rolling resistance measurements on paved and unpaved roads, contributing to a comprehensive understanding of rolling resistance in the realm of cycling sports.
