Tires, Speed Ratings

The speed rating (e.g.: "T") behind the tire size specification (e.g.: 185/65 R 14 86 T) indicates the maximum permissible speed (v_max ) for the tire.

When selecting the tires for a vehicle, ensure that their maximal permissible speed lies above the maximum speed attainable by the vehicle ("design-related").

Vehicles with National Type Approval 

For all vehicles with national type approval, the maximum speed is calculated using the following formula:

Formula for Vehicles with v_max up to 150 km/h

v_max = 1.03 x v + 3.5 km/h See Note 

Example: Indicated maximum speed v = 145 km/h

v_max = 1.03 x 145 km/h + 3.5 km/h = 152.85 km/h

In this example, a "Q" -tire or a tire with a higher-order speed rating must be used.

Formula for Vehicles with v_max from 151 km/h

v_max = 1.01 x v + 6.5 km/h See Note 

Example: Indicated maximum speed v = 163 km/h

v_max = 1.01 x 163 km/h + 6.5 km/h = 171.13 km/h

In this example, a "S" -tire or a tire with a higher-order speed rating must be used.

Vehicles with EU Type Approval 

For all vehicles with EU-registration, the maximum speed is calculated using the following formula:

v_max = 1.05 x v See Note 

Example: Indicated maximum speed v = 172 km/h

v_max = 1.05 x 172 km/h = 180.60 km/h

In this example, a "T" -tire or a tire with a higher-order speed rating must be used.

Using tires with a higher-order speed rating is permitted. The same applies for tires with higher-order load-carrying capacity characteristic number (load index).