What Does Car Tire Specification Mean?

[VonSimon]

Car tire specifications indicate the size of the tire. Below is a related introduction to tire specifications: 1. Types: Tire types include: international standard tire codes, expressed in millimeters as the section width and aspect ratio percentage. This is followed by: tire type code, rim diameter (in inches), load index (allowable load mass code), and allowable speed code. 2. Specification introduction: For small cars with displacements between 0.8-1.5, the corresponding front tire specifications range from 155/65R13 73T to 175/70R14 77H. For large cars with displacements between 1.6-6.0, the tire specifications range from 185/60R14 to 245/50R18.

[Reed]

Last time when changing tires, the mechanic taught me how to recognize these parameters. Take the common 235/55 R18 100H as an example. 235 is the width of the tire in contact with the ground, measured in millimeters; 55 is the aspect ratio, meaning the height of the tire wall as a percentage of the tire width; R stands for radial construction, which is now the standard; 18 corresponds to the rim size, measured in inches. The load index 100 at the end indicates that a single tire can bear a weight of 670 kg, and H is the speed rating, indicating a maximum speed of 210 km/h. When changing tires, these numbers must match the original specifications, especially the speed rating—don’t lower it arbitrarily, as it can be dangerous at high speeds. There’s also a production date code on the sidewall, like '2523,' which means the tire was produced in the 25th week of 2023. Tires older than 6 years should be replaced even if the tread depth is still good.

[PhoebeDella]

Our fleet pays the most attention to the load index and speed symbol in tire specifications for long-distance trips. For example, a truck tire marked 115/112R may seem complex, but in fact, 115 is the single tire load index (1215 kg), 112 is the load index when mounted in dual configuration (1120 kg), and the final R indicates a speed rating of 170 km/h. If the load index is insufficient when hauling heavy loads, the tire may bulge or even blow out. Additionally, for winter tires, look for the snowflake and mountain symbol, as they provide three times the snow traction compared to regular tires. Don't forget to rotate all the tires when seasons change, as the drive tires usually wear out faster. Besides checking the wear indicators for tire lifespan, also pay attention to rubber aging and cracks.

[StGiselle]

Just changed to off-road tires and realized there's a lot to learn about AT tire specifications. In the numbers 31×10.5 R15, 31 represents the tire diameter (in inches), 10.5 is the section width, and R15 indicates the rim size. When modifying, keep diameter changes within 3% to avoid rubbing against fenders. The M+S marking on the sidewall means mud and snow compatibility, while the three-peak mountain snowflake symbol is exclusive to winter tires. For desert driving, choose tires with beadlock design on sidewalls that can handle air pressure as low as 0.8Bar without losing the bead. Important reminder: highway tires shouldn't be used off-road - their unreinforced sidewalls are vulnerable to puncture on rocky trails. Tire pressure isn't always better when higher - 1.6Bar actually provides better mobility than 2.5Bar in sand.