UNDERSTEER VS OVERSTEER
Driving enthusiasts would likely be familiar with the terms “oversteer” and “understeer”. For casual drivers, these terms would probably mean as little as “offside” would to people who don’t watch football.
However, understanding is the road to awareness and conscientious driving, which ultimately leads to safer roads for all--so let’s get to it!
To start off, imagine this. You’re taking a left turn, and there’s a tree further up the turn on the right side of the road. Loosely put, understeer is when you hit the tree with the front of the car, and oversteer is hitting it with your rear end.
Understeer happens in taking a corner or a turn, when your front wheels lose grip. When this happens, instead of making the turn in the direction you want to go, your car drifts across the road towards the outside of the bend, in a straighter than desired line. You would experience a sudden lightness in your steering as your front tyres slide.
The key to correcting understeer is to fight the instinctive response to turn your wheel in its opposite direction even harder, hoping to force it into a turn. This would be futile because it increases what’s known as “slip angle”, as your tyres are already beyond its grip threshold, and reduces the amount of useful tyre contact with the road even further. Instead, reduce the angle of your turn towards the direction your front tyres are drifting towards, and ease up on the brakes a little (but not completely) to help your tyres regain traction, which helps you regain control of your car.
The exact corrections for understeer vary depending on what caused it. Common causes include ploughing into a corner too fast, accelerating too much or braking too hard in a corner, and low traction conditions such as wet or oily roads. Understeer is most common in front wheel drive vehicles, as their front tyres are responsible for turning and accelerating at the same time.
Oversteer occurs when the rear wheels reach the limit of traction before the front while cornering. This leads to the back of your car ‘swinging out’ and rotating around its axis. A driver would sense the rotation of the car as this happens in their seat and through the body.
Rear-wheel-drive vehicles are more prone to oversteering, pickup trucks being the most common victim, because there is less weight in the back of the vehicle. Regardless of the cause of oversteer, it is crucial to keep the front wheels pointing in the direction you’re heading towards, or your vehicle will likely spin. This is known as counter-steering or applying opposite lock. This technique can only be mastered with practice because too little would be ineffective against the tail-spin, and too much would result in a spin in the opposite direction. Once the drift has been corrected and your rear starts to regain grip, it is important to stop counter-steering at the right moment, or you may find yourself in a cascading pendulum effect.
Common causes for oversteer include entering a corner too fast, accelerating too early or aggressively, braking into or mid-corner, or lifting off the throttle mid-corner which results in the weight of the car being suddenly thrown forward. This is known as “lift off oversteer”.
Intentional, controlled oversteer is popularly known as drifting. Oversteer is understandably more exciting than understeer, but a lot more difficult to correct and has a high element of risk involved.
Learning the limits of your car is always a good thing, but if you’re keen on testing the limits of your car, be sure to practice in a safe space with safety precautions in place in the case of crashes. Taking your car to a practice track is infinitely safer than trying it on public roads.