What do the letters on tires represent?

[VanEleanor]

The letters on tires represent the speed at which the tire can carry a specified load under specified conditions. The speed levels represented by tire letters are as follows: 1. Q is 160 kilometers per hour; 2. R is 170 kilometers per hour; 3. S is 180 kilometers per hour; 4. T is 190 kilometers per hour; 5. H is 210 kilometers per hour; 6. V is 240 kilometers per hour; 7. W is 270 kilometers per hour; 8. Y is 300 kilometers per hour; 9. Z is ZR speed above 240 kilometers per hour. Methods to protect tires: 1. Check if there are any attachments on the tires; 2. Check the tire pressure when the tires are cold; 3. Reduce the driving speed in time when the road condition is poor.