What does the tire model number represent?
3 Answers
Tire model numbers represent the tire's width, aspect ratio, type, and applicable rim size. Taking the model 225/60R17 as an example, 225 indicates the tire's section width is 225mm, 60 is the aspect ratio (the ratio of the tire's sidewall height to its section width is 60%), R denotes that the tire is a radial tire, and 17 means the tire is suitable for 17-inch rims. Generally, tire widths range between 145 to 285mm in 10mm increments. The aspect ratio typically falls between 30% to 80%. Under normal circumstances, regular sedans should not use tires with an aspect ratio exceeding 75%, while luxury cars and high-performance sports cars are recommended to use tires with an aspect ratio below 60%.
The series of numbers and letters on a tire's model might seem random, but each part has its specific meaning. Take the common 205/55 R16 91V as an example. The first number, 205, refers to the tire's width in millimeters, which is the width of the part that contacts the road. The 55 represents the aspect ratio, meaning the sidewall height is 55% of the width—the smaller the number, the flatter the tire. The R doesn't stand for radius but indicates a radial structure, which is what most cars use nowadays. The 16 is the wheel diameter in inches, determining what size rims you can fit. The last part, 91V, is the most critical: 91 is the load index, meaning each tire can bear 615 kg, and V is the speed rating, allowing a maximum speed of 240 km/h. When replacing tires, these parameters must match the original factory specifications, as altering them randomly could affect the accuracy of the speedometer.
When choosing tires, I prioritize the performance parameters in the model numbers. The 205 width directly affects grip—wider tires have shorter braking distances but slightly higher fuel consumption. The 55 aspect ratio relates to comfort—lower values offer better handling and clearer road feedback, but they can feel bumpier over speed bumps. The speed rating, like V, is especially crucial. If you frequently drive on highways, opt for V-rated (240 km/h) or W-rated (270 km/h) tires. Don’t overlook the 91 load index either—if you often travel with family and luggage, choose a higher load index. Also, the 16-inch rim size must match the original specs. While larger rims look stylish, they require thinner tires, which are more prone to bulging. I recommend checking the factory tire label on the door frame or fuel cap for the correct specifications.
