What does the "service description" indicate on a tire sidewall?

The "service description" on a tire sidewall indicates the tire's load index and speed symbol, providing crucial information about its load-carrying capacity and maximum safe operating speed. The load index is a numerical code that corresponds to the maximum weight a single tire can carry when properly inflated. A higher load index indicates a greater load-carrying capacity. The speed symbol is a letter code that indicates the maximum speed at which the tire is designed to be driven for extended periods. The speed symbol ranges from A (lowest) to Y (highest). For example, a service description of "91V" means the tire has a load index of 91 and a speed symbol of V. The load index can be cross-referenced with a load index chart to determine the maximum weight in kilograms or pounds. The speed symbol V indicates a maximum speed of 240 km/h (149 mph). It is critical to use tires with a load index and speed symbol that meet or exceed the vehicle manufacturer's recommendations to ensure safe and reliable performance.