Radial tires are composed of ply, belt, crown, shoulder and bead, and the belt is used to tighten the carcass. Its characteristics are: 1) The direction of the ply cord arrangement is consistent with the meridian section of the tire. Because the cords are arranged in this way, their strength is fully utilized. The number of ply layers of radial tires is generally about 40% to 50% less than that of ordinary bias tires, and the carcass is softer. 2) The cords are only connected by rubber in the circumferential direction. Therefore, in order to withstand the large tangential force generated during driving, radial tires have several layers of cords and meridian sections at a large angle (intersection angle is 70 degrees to 75 degrees), high strength, and not easy to stretch. Circumferential annular belt layers similar to buffer layers. The belt layer is usually made of fabric cord (such as glass fiber, polyamide fiber and other high-strength materials) or steel cord with high strength and small tensile deformation. The advantages of radial tires are: 1) Large ground contact area, good adhesion, small tread slippage, and small unit pressure on the ground, so the rolling resistance is small and the service life is long. 2) The tire crown is thick and has a hard belt layer, which is not easy to puncture; it deforms little when driving and can reduce fuel consumption by 3% to 8%. 3) Because the number of cord layers is small and the sidewall is thin, 4) The radial elasticity is large, the cushioning performance is good, and the load capacity is large. The disadvantage of radial tires is that because the sidewall is thin and the crown is thick, cracks are prone to occur in the transition area between the tire and the sidewall. Large side deformation results in poor lateral stability of the car, high manufacturing technology requirements, and high cost. Because radial tires are obviously superior to ordinary bias tires, they have been widely used on cars, and radial tires are increasingly used on trucks. For example, the tires on Dongfeng EQ1090E, EQ2080E, Jiefang CA1091, Huanghe JNll82 and other truck and off-road vehicles are all radial tires.