The inner tube is a circular rubber tube with a valve installed on it for filling or discharging air. The inner tube is filled with compressed air under a certain pressure. A tire with a general air pressure of 0.5~0.7MPa is called a high-pressure tire, a tire with a pressure of 0.15~0.45MPa is called a low-pressure tire, and a tire with a pressure below 0.15MPa is called an ultra-low pressure tire. Almost all cars and trucks use low-pressure tires because they have good elasticity, wide cross-section, large contact surface with the road, thin walls, and good heat dissipation, which improves the smoothness of driving and the stability of steering control. At the same time, the lifespan of roads and tires themselves is also extended. However, due to the improvement of rubber performance, the tire load capacity has been greatly increased. Although the tire pressure is within the range of high-pressure tires, the cushioning performance of the tire still maintains the same specifications as low-pressure tires. This type of tire is still classified as low-pressure tires.