Hexadrive pulleys are the most durable variable speed pulleys available. The hexagon-shaped center shaft efficiently transmits torque through the six hex flats for maximum performance and long life. Internal drive keys, which tend to wear and shorten pulley life, are not required. In addition, because a resilient elastomer covers the shaft and eliminates metal to metal contact, no lubrication is necessary. The flanges are made of cast iron to provide a long-wearing belt contact area, and are precision-balanced for smooth operation.