21 Tooth Belt-to-Chain Drive Conversion Front Transmission Sprocket This is the front sprocket used on our popular Belt-to-Chain Drive Conversion Kit. You can swap out this from sprocket for different gearing for different applications. We also recommend using our flange nut to ensure that this sprocket is properly locked in place. Fits 1991-2020 Harley Davidson Sportster Evolution 883/1200 XL Models Recommended for use with a 530 Chain. NOTE: A larger REAR sprocket means more torque (geared down) and a larger FRONT sprocket means more top end (geared up - higher gears).