BK50-7/8" Bore Solid Pulley - 5" OD for V-belts cast iron size 4L, 5LBK50 Solid Pulley 1 Groove 5" OD 7 8" Bore Fits A, B, 4L, 5L Belts The BK50 is a solid cast pulley with a single groove, designed for smooth, efficient power transmission in belt driven systems. With a 5" outer diameter and 7 8" bore, it's compatible with A, B, 4L, and 5L section belts. Includes two hex set screws for secure shaft mounting. Outside diameter: 5" Bore: 7 8" (solid bore, not tapered) Belt compatibility: A, B, 4L, 5L Number of grooves: 1