NEW Sprocket Hub, 1" bore, 1/4" keyway with hardware Go Kart Mini Bike Hub Go kart Sprocket Hub or Mini Bike Hub 1 inch bore, 1/4 inch keyway Two bolt circles, 4 hole, 3.228 inch bolt circle and 4 hole, 2-7/8 inch bolt circle 4 inch OD. For 1 inch axle. Zinc plated. Two set screws, 4 bolts, 4 nuts and a key included. Also fits 4-1/2″ Brake Drum.