Cutting-edge tyre construction innovations combined with advanced technologies in latest model cars, have come a long way to enhance traction and the overall safety of today’s vehicles regardless of weather conditions, individual handling and the many other variables encountered on a road.
Yet, despite manufacturers making significant investment into perfecting tyre design (particularly in areas such as their grip and traction) as well as introducing ground-breaking safety advancements to assist drivers with driving and handling in all conditions — there are still circumstances where grip and traction can be lost.
Two terms known as Oversteer and Understeer, are commonly used to describe a vehicle’s behaviour in certain situations where handling is compromised as the acceleration or power applied to the vehicle pushes the tyres beyond the limits of grip. Let’s take a look at why losing grip and traction can happen and how Oversteer and Understeer occur.We will also talk about what needs to be done (usually very quickly!) to correct the situation and get the vehicle (and its occupants) safely back on track to avoid collision, damage or other serious consequences.
Oversteer usually occurs when the vehicle is turning or cornering at speed and the rear tyres loses grip and traction due to the level of the power and acceleration being applied by the driver.
Oversteer particularly occurs with rear-wheel drive vehicles (but can also occur in front-wheel drive or all-wheel drive vehicles). As power is applied in cornering, the tyres slip and lose grip as they rotate in the opposite direction, causing the back end of the vehicle to try to overtake the front.
In other words, Oversteer can be explained as the application of too much throttle, too soon while cornering. The rear tyre traction is incapacitated, causing the wheels to spin and the vehicle to slide sideways. Oversteer can also occur by sudden braking or when the driver suddenly removes their foot from the accelerator.
Understeer is something that can occur in all vehicles (not just rear drives), but with front-wheel drives being more susceptible to this experience. Also occurring as a result of harsh or sudden cornering, this term applies to a situation where speed causes the front of the vehicle to slide wide (outside of the corner), compromising the tyres’ traction and grip on the road surface and incapacitating the vehicle’s steering! In Understeer you will find the vehicle wanting to go straight despite the driver trying to turn – with the front tyres becoming overwhelmed and unable to provide the necessary grip as the corner is taken.
On a Formula One or Supercar racetrack, Oversteer and Understeer are exciting sights that we expect to see as racing drivers skilfully manoeuvre the track at speed. However, it is important to remember that these professional drivers have the special know-how and training to manage and correct Over-and Understeer in racetrack conditions, while everyday drivers should usually try to avoid these in normal driving circumstances.
So, what can be done to minimise the risk of Over- and Understeer occurring if you do get into one of these situations?
Both Oversteer and Understeer are more likely to occur in the wet (or where there is ice, snow or oil on the road) – so driving at appropriate speed to condition is vital. It therefore makes sense that the best solution for avoiding both Oversteer and Understeer in the first place is slow down and don’t drive too fast for the road and weather conditions!
If either Oversteer or Understeer has begun to take place, avoid slamming on the brakes. A slow, gradual reduction of acceleration and speed is key rather than a sudden removal of power, which will help you regain control of the vehicle. Correcting the slide is assisted by ensuring you don’t force the steering, rather turning into the skid and easing off the accelerator which will give the tyres a chance to regain their grip.
Quality tyres that are well maintained can also go a long way to ensuring Over- or Understeer is less likely to unnecessarily occur – and they will be able to cope better if it does. Additionally, correct inflation levels and tread that is not smooth or unevenly worn (along with good tyre alignment and balance) will ensure that tyres maintain optimum grip in these situations. Checking your tyres and replacing them when the tread gets worn is also vital. If in any doubt, speak to a tyre professional in your area who is trained to assist you with deciding the right time to change your tyres to ensure the safety of your ride.