Generally speaking, domestically produced cars still use tires with small width, small inner diameter, and high flatness ratio. Tires with high flatness ratios have longer tire walls and stronger cushioning capabilities, resulting in relatively higher comfort. However, they have a poorer feel on the road surface and weaker lateral resistance when turning. On the contrary, tires with low flatness ratio and large inner diameter have shorter sidewalls and wider treads. Therefore, the grounding area is large, the tire can withstand a large amount of pressure, and it is very sensitive to the road surface. It has strong lateral resistance when turning, greatly enhancing the vehicle's handling. Flatness ratio refers to the ratio of the height from the wheel rim to the tread to the maximum width measured by the tire's cross-section, expressed as a percentage, that is, the ratio of height to width. Taking the 205/60R15 specification tire as an example, the maximum width of its cross-section is 205 millimeters, the inner diameter of the tire is 15 inches, and the flatness ratio is 60. At present, most modified cars choose to increase the size during the wheel hub modification process, so the replaced tires have a smaller flatness ratio than the original tires. The advantage of this is that it can highlight the beautiful appearance of the car body. At the same time, the larger wheel hub space can accommodate larger brake calipers. At the same time, the tracking performance of the wheels is much better during driving, and the handling is significantly improved. However, it should be noted that the actual driving mileage of the modified tires may deviate from the data in the odometer. Therefore, before modifying the car wheel hub, it is necessary to choose the tires in advance, preferably close to the original mileage.