These Sprocket Hubs are spacers are to help align sprockets when doing a pulley to sprocket conversion but allow the sprocket to be bolted on and off without dealing with a spacer and longer bolts. They are available in various thicknesses to fit your application as well as flanged for the 1999 and earlier timken bearing hubs or the 2000 and later sealed bearing hubs. The inner and outer flanges help keep your pulley, sprocket, or rotor centered on the wheel hub. They are made of 6061-T6 billet aluminum.
Use the chart to match the front and rear sprocket spacing needed for your model and year.