tyre size: Specifications are the symbolic data of geometric parameters and physical properties of tires. Tyre size is usually represented by a set of numbers, with the former number representing the tire section width and the latter number representing the rim diameter, all in inches. The letters or symbols in the middle have special meanings: "X" stands for high-pressure tire; "R" and "Z" represent radial tires; "One" means a low-pressure tire. Level: Level refers to the nominal number of plies in the tire rubber layer, which is not completely consistent with the actual number of plies, and is an important indicator of tire strength. Levels are marked in Chinese, such as 12 levels; Mark in English, such as "〃14P．R〃", that is, 14 poles. Cord material: some tires are marked separately, such as "NYLON", which is generally marked after the hierarchy; Some tire manufacturers in the world mark the specifications with the first letter of Chinese Pinyin, such as 9.－2N, 7.5－2G, etc. N stands for nylon, G stands for steel wire, M stands for cotton thread and R stands for rayon. Load and air pressure: generally indicate the maximum load and the corresponding air pressure, with the load in "kg" as the unit and the air pressure as the tire pressure in "kPa". Rim specification: indicates the rim specification matched with the tire. Convenient for practical use, such as "standard rim 5.F". Balance mark: It is made of colored rubber and printed on the sidewall, indicating that the tire is the lightest here, and it should be assembled right against the valve to ensure the balance of the whole tire. Rolling direction: The tread pattern on the tire is particularly critical to the drainage and anti-skid during driving. Therefore, off-road vehicle tires with asymmetric tread patterns are often marked with arrows to mark the assembly rolling direction, so as to ensure the designed adhesion and anti-skid performance. If it is installed incorrectly, it will be counterproductive. Wear limit sign: the wear limit of the tire is marked with rubber strip and block on one side of the tire. Once the tire wear reaches this sign position, it should be replaced in time, otherwise it will burst halfway due to insufficient strength. Production batch number: a set of numbers and letters are used to indicate the manufacturing year and quantity of tires. For example, "98N8B582" means the 582th tire produced by Group B in August 1998. The production batch number is used to identify the newness and storage time of tires. Trademark: Trademark is the symbol of tire manufacturers, including trademark words and patterns, which are generally prominent and eye-catching and easy to identify. Most of them are marked with the name of the manufacturer. Other marks: such as product grade, production license number and other subsidiary marks. It can be used as reference materials and information when selecting. Tire marks are generally marked in a standardized way, and you can rest assured to purchase and use them after being clearly identified. The following is a common tyre size representation: for example, 185/7R1486H185: tread width (mm) 7: flatness ratio (tire height/tire width) R: radial structure 14: rim diameter (inch) 86: load index (indicating the corresponding maximum load is 53 kg) H: speed code (indicating the highest safety)