I would also caution you on aftermarket rear sprockets. Some will come with more holes than you need to mount to your hub. Only 1 set of the holes fit the mounting bolts perfectly. The sprocket will mount with the bigger holes as well, doing this will cause the sprocket to be out of round as the sprocket can move around the bolts on the bigger holes. You would notice this when you spin the tire and the chain is tight in some places and loose in others. If that happens check to see if you used the correct bolt holes. FYI.