I have a 2006 Staggs Sx50f completely stock gearing and chain roller. I noticed that the chain is rubbing on the bottom side of the swing arm. It is starting to wear a groove. Bike has one ride on it. Anyone else had this problem? I was thinking that the there may be to much spring tension on the roller forcing the chain to rub against the swingarm. There is no rub plate on the bottom of the swinger. The top has a nylon plate that the chain slides on but nothing on the bottom. Any help would be greatly appreciated.