Speed index truck tyres

The speed index is a code which indicates the maximum speed at which the tyre can be used and is always mentioned together with the load index. This code is also issued for off-road vehicles and vehicles which are rarely used on the road. Tyres can be used safely up to the indicated maximum speed. Over the years, tyres have been classified into speed categories with great accuracy.
Speed index truck tyres

The speed index was initially introduced to match the tyre's resistance with the (increasing) speed of the vehicle, and is based on lab testing carried out by manufacturers. Each speed range has a specific letter (or letter/number combination for the lowest categories). During testing, tyres are pressed against a large, revolving metal drum and the speed of the drum is increased until the speed required for the tyre in question.

In this example (see image), the letter ‘M’ in the combination 154/150M indicates the maximum speed.

The indicated speed index only applies to tyres which are not:

  • damaged;
  • out-dated;
  • overloaded; or
  • subject to insufficient pressure. 

Manufacturers do not guarantee the original speed index for tyres which have been repaired. After all, they cannot judge the quality of the repair.

Snelheidssymbool Maximumsnelheid (km/u) Snelheidssymbool Maximumsnelheid (km/u) Snelheidssymbool Maximumsnelheid (km/u)

A1

5 E 65 Q 160
A2 10 E 70 R 170
A3 15 F 80 S 180
A4 20 G 90 T 190
A5 25 J 100 U 200
A6 30 K 110 H 210
A7 35 L 120 V 240
A8 40 M 130 W 270
B 50 N 140 Y 300
C 60 P 150 ZR >240

 

Learn more about the load index