Full definition
A pulley (also called a sheave) with a U-shaped, semicircular, or V-shaped groove specifically designed for guiding steel wire rope or synthetic fiber cable rather than flat or V-belts. The groove profile and dimensions are matched to the cable diameter for proper support and minimum wear. Critical rule: minimum sheave diameter must be 20-30 times the cable diameter for running sheaves (D/d ratio), or 16-20x for deflection sheaves, per ISO 4308 and ASME B30.5. Smaller ratios cause excessive wire fatigue and dramatically shorten cable life. Groove material: cast iron or steel for standard duty, polyamide-lined for reduced cable wear, manganese steel for heavy duty. Applications: cranes, elevators, hoists, rigging, winches, and cable-stayed structures. Groove wear is checked with a gauge — when the groove diameter opens beyond tolerance, the sheave must be replaced or re-machined. Bearings rated for dynamic cable loads plus sheave weight.