What does the H symbol on tires mean?

[VonJuliette]

The H on a tire represents the speed rating of the tire. Each tire has this speed symbol (also known as speed rating) engraved on its sidewall, which indicates the maximum speed the tire can sustain. Below is relevant information about tire markings: 1. Tire markings refer to the information required by national standards to be displayed on both sides of the tire, including the production number, manufacturer's trademark, size specifications, ply rating, maximum load and corresponding pressure, cord ply material code in Chinese Pinyin, installation requirements, and directional rotation marks. 2. High-pressure tires are denoted by D×B, where D represents the nominal outer diameter of the tire, and B is the cross-section width of the tire, measured in inches. The 'X' signifies a high-pressure tire. Low-pressure tires are denoted by B-d, where B is the cross-section width of the tire, and d is the rim diameter. The '-' indicates a low-pressure tire. Since the cross-section width B is approximately equal to the cross-section height H, the rim size d can be calculated using the formula d = D - 2B.