The diameter of the 12r22.5 tire is 108.5cm, and the outer diameter of the new vacuum steel ring is generally 61.5cm. Then in the case of high tire pressure and high load, the outer diameter of the steel rim will be reduced to less than 59 cm. 59 cm is the critical value of the steel ring. When the diameter of the steel rim is less than 59 cm, the new tire is easy to jump out when inflated. Tires are ring elastic rubber products assembled on various vehicles or machinery, which can support the overall weight of the vehicle, bear the load of the vehicle, transmit the torque of traction and braking, and ensure the adhesion of the wheel and the road.