Load capacity and Speed Index for Earth-moving tires

Earth-moving tires and their capabilities
For earth-moving tires, the load capacity is usually indicated with a Load Index (LI) for radial tires or a PLY rating (PR) for tires with a diagonal structure. The speed capacity and load capacity are often shown together, which we call the Load/Speed Index.

Load/Speed Index for Earthmoving
For both radial and diagonal tires you will find the Load Index (LI) or PLY rating (PR), which indicates the load capacity. These values are regularly linked to the speed capacity of the tire, resulting in the so-called Load/Speed Index.

Speed categories for Earth-moving tires
For earth-moving tires we distinguish different speed categories, which are relevant for different types of heavy equipment:

• Wheel loaders: Up to 10 km/h, speed category A2
• Graders: Up to 40 km/h, speed category A8
• Articulated and rigid dumpers: Up to 50 km/h, speed category B
• Mobile cranes: Up to 70/80 km/h, speed category E/F

Driving at Higher Speeds
When a machine drives unladen on the road from point A to B, it is important to take some crucial aspects into account. It is essential to protect the relatively thick and stiff OTR tires from overheating or other potentially harmful effects. Therefore, it is advisable to leave the machine unloaded in such scenarios.