I have a Huffy 26 in. cruiser bicycle and have almost completed installation except for the fact that the chain isn't on yet. That is due to the fact that I can't get the sprocket for the chain on the rear wheel. The coaster brake is in the way. When I took the coaster brake arm off the sprocket didn't exactly fit over the hub so when I reinstalled the brake arm it was rubbing, this must be a constant problem and an easy fix so any suggestions would help. Thanks