The calculation formula of tire outer diameter D is:

D=diameter of wheel hub?tire width×aspect ratio?×2

Take 185/60R14 as Example:

185=The cross-sectional width is 185 mm?

60=The aspect ratio is 60?

R=Radial tire structure

14=Rim diameter is 14 inches

Car tire outer diameter: tire width*aspect ratio*2 tire inner diameter*25.4 (unit: mm)

Extended information:

Tires are important parts of cars. There are more than 10 kinds of markings on car tires. Correct identification of these markings is very important for tire selection, use and maintenance. It is important for ensuring driving safety and extending tire service life. important meaning.

Tire specifications: Specifications are symbolic data of tire geometric parameters and physical properties. There are three ways to express tire specifications: A. Metric (m); B. Mixed metric and imperial systems; C. Imperial system; Imperial tire specifications are often represented by a set of numbers. The first number represents the tire section width, and the latter number represents the rim diameter, both in The unit is inches. The letters or symbols in the middle have special meanings:

Tire structure: "R" represents radial tires, "D" and "一" represent bias tires.

Others: "XL" means partially reinforced tires, "TG" means engineering tractors and grade machine tires (off-road use), "NHS" means off-highway tires.

Layer

Layer: Layer refers to the nominal number of ply layers in the rubber layer of the tire, which is not completely consistent with the actual number of ply layers. It is an important indicator of tire strength. Levels are marked in Chinese, such as level 12; levels are marked in English, such as "14P.R" which means level 14.

Cord material

Cord material: Some tires are marked separately, such as "nylon" (NYLON), which is usually marked after the layer; some tire manufacturers mark it after the specifications. , expressed by the first letter of Chinese Pinyin, such as 9.00-20N, 7.50-20G, etc., N means nylon, G means steel wire, M means cotton thread, and R means rayon.

Load and air pressure

Load and air pressure: Generally, the maximum load and corresponding air pressure are marked. The load is in "kg", and the air pressure is the tire pressure in "kilopascals".

Rim specifications

Rim specifications: Indicates the rim specifications used to match the tire. Convenient for practical use, such as "Standard Rim 5.00F".

Balance mark

Balance mark: Made of colored rubber in the shape of a mark, printed on the sidewall, indicating that the tire is the lightest here. When assembling, it should be facing the valve to ensure that the entire Tire balance.

Rolling direction

Rolling direction: The pattern on the tire is particularly critical for water drainage and anti-skid during driving, so off-road vehicle tires with asymmetrical patterns are often equipped with arrows to mark the rolling direction to ensure design Adhesion, anti-slip and other properties. If installed incorrectly, it will be counterproductive.

Wear limit mark

Wear limit mark: Rubber strips and blocks are used on one side of the tire to mark the wear limit of the tire. Once the tire wear reaches this mark position, it should be replaced in time, otherwise it will cause damage. Not strong enough for a tire puncture midway.

Production batch number

Production batch number: A set of numbers and letters indicating the year, month and quantity of the tire. For example, "98N08B5820" means the 5820th tire produced by Group B in August 1998. The production batch number is used to identify the tire's condition and storage time.

Trademark

Trademark: A trademark is the logo of a tire manufacturer, including trademark text and patterns, which are generally prominent and eye-catching and easy to identify. Most of them are marked in conjunction with the name of the manufacturer.

Reference materials:

Tire_Baidu Encyclopedia