What is a speed level?
Speed rating, also called speed grade, indicates the maximum speed at which a tire can carry a specified load under specified conditions. English letters will be used on the sidewalls of different tires to indicate the speed rating of the tire. Represents the tire's certified speed rating from 4.8 km/h to 300 km/h. Today we will mainly talk about the speed rating of passenger car tires. They may affect driving safety, but few people pay attention to them - they are the speed ratings of tires.
Tires with a higher speed rating run faster, while tires with a lower speed rating run slower. This is easy to understand. The speed rating of passenger car tires starts from M, and the letters further back represent higher performance. However, the current speed limit on China's highways is 120 km/h. Nowadays, the speed rating of most passenger car tires is between S and Y, which means that the maximum withstand speed is between 180-300 km/h. In this way, almost all passenger car tire speed grades can meet the demand, but the speed grades of common tires on the market are tires with speeds above 200 per hour. What is the difference between high-speed tires and low-speed tires?
1. The higher the speed level, the safer it is to drive
Tires with high speed levels will have enhanced shoulder and tread designs in order to better cushion heat generation and tire deformation. Generally speaking, tires with a higher speed rating have better grip when the vehicle turns. Professional driver Alan Sidorov conducted a comparison test. Two identical cars used the same size tires. The car equipped with Nokian Entyre (V-level) tires decelerated from 100 km/h to zero braking distance of 35 meters, while the car equipped with Nokian Entyre (V-level) tires had a braking distance of 35 meters. The braking distance of Firestone FR710 (S-class) tires is 39 meters. And driver experiments show that the higher the speed level of the tire, the more stable the top speed steering.
2. The higher the speed level, the more durable the tire is.
China Automotive Research Center personnel said that the current speed level of tires is one of the biggest enemies of the development of tire technology. The laboratory simulates high-speed driving of tires, and it takes only 10 minutes to destroy a tire with a low speed level at a speed of 300km/h. Moreover, in experiments conducted by driver Alan Sidorov, in 45 types of road tests, the shoulders of S-class tires have been worn, while V-class tires are almost "unscathed." Tires with higher speed levels are more durable. It can be seen that the speed level of the tire not only affects the tire speed, but also affects the safety and durability of the tire to varying degrees.
3. The higher the speed level, the more expensive the tire is.
Generally, the maximum speed of tires will be much greater than the actual road speed. Some car owners think that the speed level is enough and there is no need to spend more money to buy high-speed tires. In fact, this is wrong. Although the highway speed limit is 120, in actual driving conditions, Temperature, tire pressure, wear and tear, and the material used in the tire all affect the safe speed of the tire.
If it is summer at noon, the road surface temperature can be as high as 40-50 degrees Celsius. Coupled with the heat generated during tire rotation, the tire temperature can rise to more than 60 degrees Celsius. At this time, most entry-level cars are equipped with "T" ( 190km/h) will be greatly reduced, and the safe speed will be reduced to 130km/h. This does not take into account factors such as tire pressure, tire wear, etc. If all factors are taken into account, the actual safe speed of T-class tires may continue to be It can't reach 120km/h, so if possible, choose tires with a high speed rating.
