Carmakers are required to fit tyres that can match a car's top speed
A common misconception is that a tyre with a high-speed rating will be a better handling tyre.
It's not necessarily the case, although most high performance tyres do exhibit better road handling characteristics.
The 'speed rating' of a tyre shown on the tyre sidewall is the speed it can withstand for a period of time without disintegrating. It is measured by running the tyre, under load, against a large drum.
To achieve a speed rating the tyre is run at different speeds for periods of time according to an accepted international standard.
Common speed ratings are:
- S 180 km/h
- T 190 km/h
- U 200 km/h
- H 210 km/h
- V 240 km/h
- W (ZR) 270 km/h
- Y (ZR) 300 km/h
- ZR Above 240 km/h
Carmakers are required to fit tyres that can match a car's top speed, but when owners come to fit replacement tyres to their car they have to be minimum of S rated, which is 180 km/h.
The speed rating is moulded into the sidewall of all tyres along with the size and load rating.