What does "L" refer to in the following tyre designation: 315/80 R 22.5 156/150 L?

The letter "L" on a tyre refers to the maximum permissible speed rating of that tyre. In German and international tyre designation, each letter corresponds to a specific maximum speed the tyre can safely handle. This is important for ensuring safety and performance, as using tyres with an insufficient speed rating for your vehicle or driving conditions can be dangerous.

For example, "L" corresponds to a maximum speed of 120 km/h. Other letters represent different speed limits (like "H" for 210 km/h or "V" for 240 km/h). This rating helps drivers choose tyres appropriate for their speed needs and vehicle specifications.

The other numbers and codes on the tyre describe its size, load capacity, and type, but the letter specifically indicates the speed rating. So seeing "L" tells you the tyre should not be driven over 120 km/h to maintain safety and optimal performance.