The wheel that is used in the Koepe winder instead of a winding drum. It usually consists of a cast-steel hub with steel arms and rim of welded construction. The diameter of the sheave varies from about 16 to 26 ft (4.9 to 7.9 m), depending on the size and type of winding rope and the total load. It is recommended that the ratio of the diameter of the sheave to the diameter of the rope should be 100:1 and that of the sheave to the largest wire in the rope, 2,000:1. A Koepe sheave is fitted with renewable friction linings.