Transmits tyre traction or braking forces, so a relative movement arises between the road and the tyre, i.e. the peripheral speed of the wheel is smaller or greater than the car speed.
That difference is called wheel slip. However, the wheel slip is an undesirable effect that impairs driving safety. This phenomenon can be limited through the proper and balanced load of the wheels, as well as through anti-slip tyres with large contact surfaces. It is effective to the traction control in SEAT ESR or TCS and also against slippage during braking (ABS).