The sprocket wear indicator indicates the condition of the rear sprocket. It can be used to check sprockets from 12 to 21 teeth. Procedure: With the chain on the sprocket, place the indicator with the ball end between two teeth on the top of the sprocket. The last chain link is removed from the sprocket with a force of 100 N or 10 kg by pulling the tool in the direction of sprocket rotation. Remove the last chain link from the sprocket. If it comes off easily, the sprocket is in good condition. However, if the link overlaps the adjacent tooth or requires force to remove it, the sprocket is worn and should be replaced.