Radial tire radial arrangement like the earth, the cord angle is small, usually 0 degrees, not to maintain the intersection between the carcass cords, when the tire in the running process, the crown around the stress increase, will cause the circumferential stretch, carcass radial gap. Close to the circumferential direction dealing with cord layer so the buffer layer of radial tire, 90 degrees intersect with the cord angle, generally 70 to 78 degrees, forming a rigid ring with hardly done, the whole tire fixed, tire circumferential deformation, the stress buffer 60% to 70% layer under the entire tire, become the main force components of radial tire