Safe driving and tyre features

n the tyre sidewall there are several different inscriptions. As well as the name of the brand and the range, the size and characteristics of the tyres are marked: nominal width, ratio between nominal section height and nominal section width, structure or construction code, rim diameter and load and speed index.

The tyre pressure has a strong influence to the safety and economy of a vehicle.
Tyre pressure when cold (never try to adjust the pressure while the tyre is hot) must therefore be checked regularly (every month), especially before a long trip.
Braking distance is related to the tyre pressure. At a driving speed of 100km/h, the braking distance with correctly inflated tyres will be 40m compared to 42.4m with deflated tyres. Performance is therefore improved by almost 6%, equal to 2.4m.
Incorrect inflation pressure causes irregular tyre wear. Pressure that is too low causes shoulder wear and carries the risk of structurally damaging the tyre. Pressure that is too high causes wear to the centre of the tyre.

A tyre is made of rubber, steel and fibres. Steel and fibres are structural materials, the rubber has the function of protecting them against environmental influences. The rubber itself can be damaged by chemicals or other environmental influences:

• Sharp objects, strong impacts or other mistreatment can cause visible and invisible structural defects
• Also tyre pressure that is too low causes structural defects
• High temperatures and sunlight can destroy the rubber

The tread depth is a substantial safety factor. It has an important influence on the vehicle’s contact with the ground.
While braking, the Anti-lock Braking System is controlling the wheel at the slip threshold and water is collected. The tyre tread becomes saturated and the braking distance increases drastically.
Hydroplaning depends on water depth, tread depth and driving speed. In order to measure hydroplaning, a car is driven into a basin with 8 mm of water and speeds up. As soon as the motor works harder without speeding up, hydroplaning starts.

The correct choice of seasonal change-over is fundamental for safe driving. Summer tyres in summer, winter tyres in winter. Braking distance, traction and stability all strongly depend on the adequate rubber compound.
Winter tyres not only ensure grip on snow, they perform better than summer tyres whenever the temperature drops below 7°C. Pirelli recommends fitting winter tyres to ensure mobility on every surface and in all cold weather conditions. From +7°C and under, summer tyres have longer braking distances, and drastically less grip on snow.