Tire speed ratio

The speed factor describes the maximum speed that a car can reach with these tires.

The speed factor describes the maximum speed that a car can reach with these tires.

It also informs indirectly about the ability of the tire to transmit the power developed by the car's engine. If the vehicle is fitted with tires with a V index (maximum speed of 240 km/h) from the factory, and the driver drives slower and does not develop such high speeds, then cheaper tires with a speed index T (up to 190 km/h) cannot be used.

Vehicle power is used when starting off, especially when overtaking, and tire design must take this into account.