What Are the Grades of Tires?

[VonJayla]

Tire grades are divided into load index and speed rating. The load index is molded on the sidewall of the tire, indicating the maximum load capacity of the tire. For driving safety, this load limit should not be exceeded. The speed rating indicates the maximum speed at which the tire can carry a specified load under defined conditions. For example, if a tire model is: 205/55R16-91V, where 91 is the load index of the tire and V is the speed rating. By referring to the tire load index and speed rating comparison table, we can determine that the maximum load capacity of this tire is 615kg, and the permitted maximum speed is 240km/h. Below are some precautions for using car tires: 1. Regularly check the tire surface for cracks, deformations, or other defects. The tread grooves gradually become shallower due to wear from driving. If they become flat, the tire will lose its functions such as water drainage and anti-skidding, significantly reducing the car's performance. Moreover, seemingly minor cracks can be potential hazards for tire blowouts at high speeds. Also, ensure to promptly remove small stones lodged in the grooves. 2. Avoid parking the vehicle on roads with large, sharp, or pointed stones. Do not park the vehicle near or in contact with petroleum products, acidic substances, or other materials that may deteriorate rubber. Drivers should avoid turning the steering wheel after parking, as this action accelerates tire wear. 3. Tires are prone to overheating during prolonged or high-speed driving in summer, with increased air pressure. In such cases, the vehicle should be stopped to allow the tires to cool down. It is strictly prohibited to release air to reduce pressure or splash water to cool the tires, as these actions may lead to abnormal aging of the tread rubber.

[DeMarley]

There are various tire grading categories. For instance, the speed rating uses letters to indicate the maximum safe speed, such as T for 190 km/h and H for 210 km/h. The load index is represented by numbers, like 91 indicating a capacity to bear 615 kg, which must match the vehicle's weight to prevent blowout risks. There's also the UTQG system, which includes the treadwear rating (e.g., 200 means the least durable, while 500+ indicates exceptional durability), traction grades (A signifies the best wet-road grip, with B and C being inferior), and temperature grades (A denotes the best heat dissipation, while B and C may pose issues in hot weather). Over the years when changing tires, I always prioritize those with traction grade A, especially for safer driving in rain or snow—never compromise safety to save a little money. High treadwear tires last longer, saving costs in the long run. Check the sidewall markings, consult your manual or a technician when replacing tires, and ensure they suit your vehicle model perfectly—never make random choices.

[FelixDella]

I believe tire ratings are crucial for driving safety: The speed rating ensures your tires can handle the limit even when you're not speeding—for example, 'S' represents a maximum of 180 km/h. The load index, like 95 corresponding to 690 kg, prevents overloading and tire damage. In the UTQG system, the traction rating is vital, with 'A' offering the best wet-road control to avoid skidding accidents. A high temperature rating, such as 'A,' prevents overheating on long trips. A treadwear index above 300 indicates better durability. As a family driver, I particularly prioritize traction and temperature ratings to ensure safe travels for my loved ones. Regularly checking tire pressure and wear, combined with the correct ratings, can improve fuel efficiency and extend tire life. When choosing tires, don’t just focus on the brand—understanding the labels is key.

[Alessandra]

Tire grades include speed symbols such as V indicating suitability for high speeds up to 240km/h; the higher the load index number, the greater the weight-bearing capacity; UTQG ratings cover treadwear, traction, and temperature grades. I prefer tires with higher speed ratings to enhance driving stability; don't overemphasize treadwear ratings, as slightly lower ones may offer better grip. Choose according to seasons - prioritize cooling performance in summer and opt for higher traction grades in winter. This knowledge helps optimize my daily commute.