Oversteer

Oversteer is a phenomenon that can occur in an automobile which is attempting to turn. The car is said to oversteer when the rear wheels do not track behind the front wheels but instead slide out toward the outside of the turn. Oversteer can throw the car into a spin.

The tendency of a car to oversteer is affected by several factors such as mechanical traction, aerodynamics and suspension, and driver control. The driving technique called opposite lock is meant to cope in this circumstance.

Limit oversteer happens when the rear tires exceed the limits of their lateral traction during a cornering situation before the front tires do, thus causing the rear of the vehicle to head towards the outside of the corner. More generally oversteer is the condition when the slip angle of the rear tires exceeds that of the front tires.

Rear wheel drive cars are generally more prone to oversteer, in particular when applying power in a tight corner. This occurs because the rear tires must handle both the lateral cornering force and engine torque.

In modern race cars, especially open-wheel race cars, oversteering in high speed turns is caused mainly by aerodynamic configuration[citation needed]. In this respect, a heavier aerodynamic load on the front of the car relative to the rear causes it to oversteer. Oversteer in low speed turns is often reduced or eliminated electronically through traction control (if the sanctioning body allows their use). Nevertheless, the required front/rear balance to make the cars fast through corners is obtained by setting up the aerodynamics and balancing the suspension. The car’s tendency toward oversteer is generally increased by softening the front suspension or stiffening the rear suspension. Camber angles, ride height, and tire pressures can also be used to tune the balance of the car.

An oversteering car is alternatively referred to as ‘loose’ or ‘tail happy’.

How do you differentiate Oversteer and Understeer?
The racing driver’s joke is “When you see the tree you’re about to hit, it’s called understeer. When you can only hear and feel it, it’s oversteer.” Another is “Oversteer is when the passenger is scared; Understeer is when the driver is scared.” To put things in even simpler terms, when you turn into a corner, oversteer is when the car turns more than you expected and understeer is when it turns less than you expect.