flat belts and round belts are made of urethane or rubber-impregnated fabric reinforced with steel or nylon cords to take the tension load. One or both surfaces may have friction surface coating. Flat belts find considerable use in application requiring small pulley diameters. Most often. Both driver and driven pulleys lic in the same vertical plane. Flat belts are quiet and efficient at hight speed. And they can transmit large amounts of power. However. A flat belt must operate with higher tension to transmit the same torque as a V belt. Crowned pulleys are use for flat belts, round belts run in grooved pulleys or sheaves. Deep-groove pulleys are employed for the drives that transmit power between horizontal and vertical shafts, or so-called quarter-turn drives, and for relativeely long center distances.