Get to grips with tyres

WORDS_JAMES SCOLTOCK

Tyres are a vehicle’s sole contact with the road. A welllooked-after tyre designed for all conditions is arguably the most important piece of technology on a car to help keep it moving safely. The engineering that goes into designing the shoes of the car is incredible, meaning that no matter the conditions – with options for summer, winter and all-season – performance remains constant.

Tyres consist of a number of different rubber compounds that offer varying levels of viscosity and elasticity. Depending on the mix, they deliver exactly the right attributes for every eventuality, whether you’re track racing, delivery driving, or Sunday driving.

Beneath the rubber sits a range of plies, from nylon cord embedded in rubber to enhance high-speed suitability, to steel cord for belt plies to aid shape retention and directional stability. Textile cord plies also help control the internal pressure and maintain the tyre’s shape.

As the industry shifts from combustion to electricity, tyre technology is continually being developed to make it better able to cope with the increased weight and torque attributes of EVs.

Tread Made from synthetic and natural rubber, the tread is comprised of three sections: the cap, which is responsible for gripping the road and providing directional stability and wear-andtear resistance; the base, which reduces rolling resistance and damage to the casing; and the shoulder, which forms an optimal transition from the tread to the side wall. The rubber compounds used in the construction of the tyre and its tread will define performance in different environmental conditions, under load, and durability.

The inner liner Most vehicle tyres won’t have an inner tube, so they need to be airtight. The inner liner is typically made from butyl rubber and seals the air-filled inner chamber, acting as a tube in tubeless tyres.

Breaker The breaker stops the tyre growing as speed and temperature increase, while improving lateral stability. In essence, the breaker delivers more strength during high performance or in high-speed conditions.

Side wall Protects the casing from external damage and atmospheric conditions. Information about the tyre can also be found on the side wall, including width, aspect ratio, wheel diameter and speed rating.

Bead The tyre’s bead is made up of a number of components, including the reinforcement. Made from nylon and aramid fibres, this can enhance directional stability and ensure steering precision. The bead apex, a synthetic, rubber material, also improves directional stability and steering precision, while improving comfort and the bead core. Finally, a steel wire embedded in rubber ensures the tyre sits firmly on its rim.

Abrasion gum Consisting of a special rubber with very low hysteresis and viscous attributes, abrasion gum increases abrasion resistance, making it difficult to wear down and improving the tyre’s durability.