Classes D and G are not used.
For a car which is moving with speed of 80 km/h in case of full braking, the braking distance for a set of four identical tyres class A is up to 18 meters shorter than a set of tyres class F! This is a significant difference and could be crucial emergency situation.
Wet grip is very important characteristic in terms of safety and depends on the ability of the tyre to stop the vehicle quickly on wet surface. The difference between the braking distance between A and G could be up to 30%*.
Class A (shortest braking distance) to class G (longest braking distance)
*When measured by the test methods, set out in Regulation EC 12222/2009 braking distance can vary depending on the driving conditions and other factors.