Offset Chain-Drive Sprockets - 21 Tooth 520 Conversion

21 Tooth 520 Conversion

This 21-tooth offset countershaft sprocket is designed for a 520 chain conversion, allowing a switch from belt to chain drive for compatibility with a wider rear tire. Constructed from high-grade chromoly steel (8620), it is CNC-machined, case-hardened, and finished with electroless nickel plating for enhanced wear resistance, corrosion protection, and lubricity. The sprocket is heat-treated for durability and broached to maximize spline-to-shaft contact. It is drilled and tapped to accommodate a late-model lock plate, which is available separately. Offset measurement is taken from the face that rests against the main shaft bearing to the inside of the teeth. Drive chains are sold separately.