What does the wheel specification 245/55r19 mean?

[RyanAnn]

245/55r19 refers to the tire specification, where 245 indicates that the tire section width is 245 millimeters; 55 is the aspect ratio, which means the ratio of the tire sidewall height to the tire section width is 55%; R indicates that the tire has a radial construction, meaning it is a radial tire; 19 refers to the rim diameter of 19 inches. The combination of numbers and letters in 245/55r19 represents the key parameter information of the tire, followed by the load index and speed rating. When selecting tires, it is essential to consider all parameters based on specific conditions. Tires are the only components of a car that come into contact with the ground, affecting the vehicle's driving stability and safety. Tires are rubber products, and prolonged use can lead to aging, so they need to be replaced regularly. Typically, tires installed on a car can last for four years. When purchasing new tires, always check the production date, as unused tires generally have a shelf life of three years. In addition to the model, tires also display the following common data: The sidewall of the tire may have an arrow or the word "OUTERSIDE," indicating the tire's rotation direction. A small umbrella symbol on the sidewall indicates that the tire is suitable for driving in rainy or slippery conditions. Some tires may also include other letters or symbols with special meanings, such as "X" for high-pressure tires, "C" for reinforced tires, "B" for bias-ply tires, and "-" for low-pressure tires. Tire cord materials: Represented by Chinese pinyin, such as M for cotton cord, R for rayon cord, N for nylon cord, G for steel cord, and ZG for steel radial cord tires. Speed rating: Indicates the maximum speed at which the tire can carry a specified load under defined conditions. Letters A to Z represent certified speed ratings ranging from 4.8 km/h to 300 km/h. Common speed ratings include: Q: 160 km/h; H: 210 km/h; V: 240 km/h; W: 270 km/h; Y: 300 km/h. Rim specification: Indicates the rim size compatible with the tire for practical use, e.g., standard rim 5.00F. During daily use of tires, pay attention to the following points: Regularly inspect the tire surface for cracks, deformations, or other defects. Due to wear from driving, the tread grooves gradually become shallower. If the tread wears out, it loses its drainage and anti-slip functions, significantly reducing the car's performance. Small cracks can also pose a risk of tire blowouts at high speeds. Additionally, promptly remove pebbles lodged in the grooves. Park on level ground whenever possible. Avoid parking on roads with thick, sharp, or pointed stones. Do not park near or in contact with petroleum products, acids, or other materials that can deteriorate rubber. After parking, avoid turning the steering wheel, as this accelerates tire wear. Do not splash water to cool tires. In hot weather or during high-speed driving, tires can overheat, and pressure may increase. In such cases, stop to allow the tires to cool naturally. Never release air to reduce pressure or splash water to cool the tires, as this can cause abnormal aging of the tread rubber. Avoid sudden braking. Try to minimize frequent or hard braking to prevent accelerated tread wear caused by dragging the tires against the road surface.