What do the speed rating letters on car tires represent?
1 Answers
Car tire speed rating letters indicate the maximum speed at which the tire can carry a specified load under defined conditions. Different letters represent different speed ratings, with most passenger car tires falling between S and Y, corresponding to maximum load-bearing speeds ranging from 180 to 300 km/h. As rubber products, tires gradually lose their load-bearing capacity over time due to aging. Additionally, heat generated from rising road temperatures and the compression/deformation during rolling significantly reduces the tire's actual maximum speed capability. Therefore, manufacturers typically equip vehicles with tires rated several levels higher than the maximum required speed to ensure safety.