The load rating of a tyre is a numerical indication of the maximum load that a tyre can carry at the speed indicated by its speed symbol and at a given inflation pressure. Along with the tyres speed rating it forms what is commonly referred to as the "service description".
Below is a table of load ratings relating to car tyres:
However, it must be noted that all load ratings, regardless of the tyres speed symbol, are for a maximum of 210 km/h (130 mph). After this speed the maximum load rating should be reduced.
Some tyres, notably ZR rated, do not carry a service description. In this case it is advisable to consult the tyre manufacturer to determine maximum loads applicable.