Oregon Power Mate Sprocket System has a replaceable free-floating rim. The advantages of a rim-type sprocket are that (1) the rim can float on the clutch cup's spline, allowing the rim and chain to align with the bar, and (2) the rim is replaceable, extending the overall life and economy of the sprocket system. Bearings and other specialized replacement components are also available from Oregon to help keep your sprocket in service for a long time.