The production of these valve belts begins with a fabric / rubber mat that is sewn together in the first operation to obtain a roll which is then mounted on the vulcanization mold with specific tooth profile. In the course of the following operations, various layers of rubber material and the tensile strand are applied and vulcanized together. The tensile strand (made of fiberglass) transmits the main train load and gives the belt additional stability. This tension cord is a continuous material which has not been joined and therefore gives the belt the tensile strength. The seam visible on the inside at one point is therefore not a stabilizing feature. .
