Rolling Resistance
Rolling resistance is the force needed to keep a rolling tyre in motion.
The energy used to roll the tyre generally expresses as rubber deformation.
Most of that energy is recovered by rubber spring-back, though some is lost due to tread rubber hysteresis.
The tread component typically consumes much of the lost energy.
Rolling resistance is heavily influenced by the tread compound and also impacted by the pattern and structure of the tread.
Higher rolling resistance is generally less desirable, especially in recent decades, as tyre manufacturers focus their attention on maximising fuel efficiency in tyres.
A tyre engineer seeking to optimise rolling resistance will choose a thick tread and avoid any compounding or design decisions that would lead to softness or excess deformation in the tread.
Testing for Rolling Resistance
The vast majority of rolling resistance testing is conducted on a dynamometer test rig that has been specifically designed for rolling resistance testing.
Standardised tests are commonly used. There are also some on-vehicle test methods that measure rolling resistance via coast-down.
This information has been reproduced with the kind permission of Smithers
Smithers is an independent, third-party testing and consulting company with a history in the tyre industry starting back in 1925. Their team has many years of experience in the tyre and rubber industries and have created this information as an educational resource on the general science behind tread development.
As an organisation, Smithers do not actively develop tyre treads for commercial use in the market.
Tread design is a complex, highly specialised activity that must take into account each manufacturer’s design and development goals.
© SMITHERS, 2021