Hi-Cap® sheaves (narrow V-belts) are manufactured from class 30 gray iron (30000 lb tensile strength) and can have a maximum speed of 6500 fpm. All Martin sheaves are statically balanced. Dynamic balancing should be considered for any sheaves exceeding 5000 lb. Martin Hi-Cap® Wedge Sheave, Type J Web, Bushed Bore, 0.75 to 2.688 in Bore, 6-1/2 in OD, 6.45 in Pitch Diameter, 6 Grooves, 2.718 in Face Width, MST® Q1 Bushing, For Use With: 3V Cross Section Belts, Steel