Load and speed index of truck tyres

Where can I find the load index?

The load index indicates how much weight the tyre is able to cope with (at the correct tyre pressure). The accompanying code can be found on the side of the tyre. Never exceed the load index mentioned on the tyre! The load index is used together with the speed index, which indicates the maximum speed at which you can drive with a tyre.

Tyre pressure and tyre load capacity

A tyre's maximum load capacity only applies if the tyre also has an appropriate tyre pressure. Regularly checking tyre pressure has several positive effects:

• the truck/trailer can be loaded to the maximum limit;
• the tyre will have a longer life-span;
• there will be a positive impact on fuel economy; 
• improved safety is guaranteed; and
• saving of costs.

Load index at least equal to the original

When changing truck tyres, it is important for the load index of the new tyre to be the same as that of the original tyre. A higher load index isn't a problem, but a lower load index should never be selected. Tyres will only be safe if this basic principle is complied with. If tyres with an identical load index are mounted on a single axle, the required minimum load index applies to each tyre on the axle. If a tyre on one side has a high load index, this will in no way compensate for a tyre on the other side of the same axle, which has an insufficient load index.

Loadindex of tyres

Speed index of 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.

The speed index was initially introduced to match the tyres 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.

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

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

Speedindex of truck tyres

Would you like to know more?

Do you need advice? Please contact us, our experts will be pleased to assist you. Contact our experts at +31 (0)523 - 850 850 or by e-mail to info@heuver.com. You can also read all about trucks on the truck knowledge-page.