The first two months that I had my HH it shifted like a dream. Then all of a sudden the top rear derailler pulley started rubbing the largset cog on the 11-34 rear cassette. I changed the rear der. hanger but I still had the problem. My LBS couldn't find anything wrong but they put a different B tension screw into the XTR rear derailler that was longer and it pushed the pulley away from the cassette. It was fine for a couple more months but now the top pulley is rubbing the cassette again. I just brought it back to the LBS and they are going to check it out. Has anyone had this problew before?