Tyres are arguably the most important piece of car safety and performance equipment on a motor vehicle. They are the glue that keeps your vehicle on the road allowing the driver to follow a defined path. Without a minimum level of grip between the tyre and the road surface no forward momentum can be achieved. Once momentum is achieved, the best tyre grip ensures the driver can maintain control over vehicle direction and most importantly to safely bring it to a stop.
The four contact areas between the tyre and the ground surface with the resultant coefficient of friction is the only means through which the driver can affect vehicle control. Tyre grip is the ultimate limiting factor for acceleration, braking and directional control. Without tyre grip, no control is possible. For example, if a vehicle suddenly hits a patch of ice the loss of tyre grip often results in an accident as the vehicle slides out of control off the road.
The best tyres for a given vehicle provide the highest level of grip for the particular road condition. This means that the best tyre depends on the road surface on which the vehicle is being driven. For example, motorsport vehicles often use a tyre with no tread known as a ‘slick’ when the vehicle is driven on a smooth surface in dry conditions to increase the contact surface and therefore grip. If however it starts to rain and the circuit surface becomes excessively wet, the ‘slick’ tyre will aquaplane (float) on the water and grip is reduced to almost zero. The competitors then need to immediately change their tyres to one with a tread pattern that redirects the water away to maintain contact between the tyre and road surface so that some grip is maintained. Different road surfaces and tyre compounds (chemical composition) with varying levels of coefficient of friction, tread patterns and different temperatures also have a significant influence of the level of grip.
It is impractical, however, for a road vehicle to continually change the tyres as the weather and road surface changes, therefore the best tyres for a road vehicle are somewhat of a compromise of rubber compound and tread pattern to suit a range of conditions. There are, however, two very broad categories known as ‘road tyres’ and ‘off road 4wd tyres’. As the name implies these categories contain tyres more suited in both compound and tread pattern to the two quite different surfaces of bitumen or formed surface and one of loose gravel or dirt.
Within these two categories, however, there is a plethora of types of tyres from ‘sports’ to ‘long wear’, low or high profile, 4x4 off-road, All-Terrain, Mud & Snow and All-Rounder. There are quite literally thousands of different sizes makes and configurations to choose from.
So how does one make the best tyre choice in terms of tyre size and type? Firstly, it depends on the type of vehicle and then on the conditions of use. The best advice is to be guided by the experts and there is no better expert than the engineers who designed and built your particular type of vehicle. During the development process, manufacturers spend countless man-hours selecting the best tyre and then tuning the vehicle suspension, brakes and other control systems to get the best out of that particular tyre.
So when you need to replace your tyres the best tyre for the job is the one that was original equipment unless of course you specifically want to use your vehicle for a particular purpose. For example, a significant amount of off-road use or driving in snow conditions would require a tyre that is better suited to those specific conditions. In this case again refer to the experts for advice, a retailer or tyre supplier.
Regardless of the type of tyre, maintenance is of utmost importance. Ensuring the tyre pressure is always within the range specified by the vehicle manufacturer is particularly important. This information can be found on the tyre pressure guide placard situated on the drivers side door opening.
An under inflated tyre creates more rolling resistance and therefore more fuel consumption. By keeping your tyres inflated to their proper levels, you help to maximise your car's fuel economy. An under inflated tyre can also result in catastrophic failure that may cause a potential accident situation due to loss of tyre grip. Over inflated tyres not only result in deterioration in ride comfort but also impact on vehicle handling performance and tyre wear.
In some conditions, such as driving on snow, it is desirable to reduce the tyre pressures from the standard recommendation to achieve a higher grip threshold. Refer to your owner’s manual for specific recommendations, but ensure that whatever changes you make to return the pressure to the standard recommendation when you return to normal driving conditions.
Lastly, wheels should be rotated front to back as per the maintenance schedule and owners manual to ensure even wear and maximum life is achieved from your tyres.