Narrow V belt SPZ SPA SPB SPC, each type of triangle belt defines the section size of triangle belt.   At the same time, the minimum diameter of the small belt pulley corresponding to each wheel groove Angle of each type of triangle belt is specified, but the large belt pulley is not specified.  The belt pulley groove Angle is divided into 34 degrees 38 degrees, the specific selection should be based on the belt pulley groove type and benchmark diameter selection;  The slot Angle of the belt pulley is related to the diameter of the belt pulley. The recommended slot angles of different types of belt pulley in different diameters are as follows: SPA V-belt pulley When the pulley diameter <=118mm, the Angle is 34 degrees.  SPA V-belt pulley When the pulley diameter >118mm, the Angle is 38 degrees.