Shimano Alivio M3100 9 Speed Rear Derailleur The SHIMANO ALIVIO RD-M3100 9-speed rear derailleur delivers a low profile design that lets you ride aggressively with fewer interruptions thanks to its SHIMANO SHADOW design. The SHIMANO ALIVIO M3100 2×9-speed or 3×9-speed drivetrains receive new updated shifters and derailleurs. SHIMANO ALIVIO utilizes Shimano hallmark technologies including SHIMANO SHADOW RD derailleurs and RAPIDFIRE PLUS MONO technology in the left shifter to simplify the riding experience. New SHIMANO ALIVIO M3100 utilizes HG shifting for smooth gear changes.