The tire specifications for the BMW X5 2022 xDrive 40Li Premium M Sport Package are 275/40 R21 and 315/35 R21; for the BMW X5 2022 xDrive 30Li Premium M Sport Package, they are 275/45 R20 and 305/40 R20. The numbers 275, 305, and 315 represent the tire's section width in millimeters (275mm, 305mm, and 315mm, respectively). The numbers 45, 40, and 35 indicate the aspect ratio of the tire's section height to its width (45%, 40%, and 35%, respectively). The 'R' stands for radial construction, and the numbers 20 and 21 denote the rim diameter in inches. The front tires of the car are slightly larger in diameter, but the tire pressure differs between the front and rear tires. The front tire pressure is 3.2 bar when unloaded and 3.9 bar when fully loaded, while the rear tire pressure is 3.5 bar when unloaded and 4.6 bar when fully loaded. Higher tire pressure increases the tire diameter, but during normal use of the BMW X5, the diameters of the front and rear tires are almost identical. The BMW X5 does not experience abnormal tire wear, speed inaccuracies, or tire pressure warning light issues due to the slight difference in tire sizes. Tires are the only components of a car that come into direct contact with the ground, and they play a crucial role in the vehicle's driving stability and safety. The BMW X5 features an on-demand all-wheel-drive system, but it primarily operates as a rear-wheel-drive vehicle. This design gives the rear tires a wider width, providing enhanced grip. The front wheels are only engaged to distribute power when the rear wheels slip or under specific road conditions. In addition to the model specifications, tires also display the following common data: Tire cord material: Indicated by Chinese pinyin, such as M for cotton cord, R for rayon cord, N for nylon cord, G for steel cord, and ZG for steel radial cord. Speed rating: Indicates the maximum speed at which the tire can carry a specified load under defined conditions. Letters from A to Z represent certified speed ratings ranging from 4.8 km/h to 300 km/h. Common speed ratings include: Q: 160 km/h; H: 210 km/h; V: 240 km/h; W: 270 km/h; Y: 300 km/h. Rim specification: Shows the rim size compatible with the tire for practical use, such as 'Standard Rim 5.00F'.
