The physics of slip angle: why sliding actually makes you faster – Jalopnik

One of the concepts in vehicle dynamics that is often misunderstood, but essential to gaining a competitive advantage, is the slip angle. Imagine taking a turn at high speed on a race track. There is a point where your wheels point in a different direction than the vehicle’s direction of travel. It’s more dramatic at higher speeds and it happens in all kinds of cornering scenarios (not just on the track), but the difference between the direction of your car and the tires is the slip angle. When drifting, the slip angle is much more dramatic. But the optimal slip angle for maximum performance is right on the edge.

Slip angle allows a vehicle to achieve optimal grip for better handling performance, without losing speed. As the slip angle increases (around a corner), the lateral force on the tires also increases, but they can only handle it up to a certain point (peak grip) before you gradually start to lose traction. The ideal slip angle is not a static measurement, and depending on whether you use street tires or racing tires, it can be at very different points during a fast turn.

The drive recently broke the slip angle, demonstrating the concept on track, with the driver making many steering adjustments in the turns. Finding the right slip angle goes beyond just finding the optimal balance, because maintaining that ideal slip angle through a turn is the real challenge. And from the driver’s perspective, constant steering adjustments are required during the turn.

Regardless of whether they are standard all-season tires or enhanced performance tires for summer driving, each tire has a portion of its surface that is in constant contact with the road surface. It is of course called the contact patch. Rubber is flexible, so even if the wheel is tilted slightly to one side, the contact patch can point forward. This causes deformation of the tire as a greater lateral load is placed on the rubber in contact with the ground. When a driver successfully uses the optimal slip angle, he will appear to be sliding slightly around the corner, without the wonderful wandering side effect of smoke pouring from the tires.

Knowledge of the slip angle is also useful outside of motorsport, because it helps explain certain driving characteristics. The slip angle can differ between the front and rear of a vehicle, significantly affecting cornering ability. A larger slip angle at the rear of the car compared to the front causes oversteer. More front slip angle, and you have understeer. An equal slip angle at the front and rear of the car generally results in neutral driving behavior. Weight distribution is a major factor in a car’s slip angle, so nose-heavy cars from automakers like Audi are known for understeer.