Rear

The heart of this microSHIFT Acolyte derailleur is the innovative SpringLock system. By pairing a customized linear rate high tension spring and a dual stage activation mechanism, we’ve developed a system that can provide substantial chain security when you need it and can be turned off when you don’t.  To engage the clutch, turn the engagement bolt clockwise until it clicks. There’s no way to overtighten the bolt. To disengage the clutch for wheel removal, flip the switch. It’s that simple. - Innovative SpringLock chain retention keeps chain in place over rough terrain - Direct path cable routing for smooth and responsive shifting - Compatible with 12-42T and 12-46T 8-speed cassettes - Compatible with Acolyte shifters only

M21 rear derailleurs are designed to work with 6- and 7-speed Shimano road and mountain shifters. Enjoy the wide variety of bikes you can get going again with M21 rear derailleurs. - Robust composite and steel construction - Compatible with Shimano 6- and 7-speed mountain and road systems - Long cage for double or triple cranksets and 32T max cassette cog - Includes frame hanger attachment for use with older frame designs

M-series rear derailleurs are designed to work with 7, 8, and 9-speed Shimano-compatible mountain and road shifters. These legendary M26 rear derailleurs put cyclists of all ages back on their saddles with as little frustration as possible. - Robust composite and steel construction - Compatible with Shimano 7, 8, and 9-speed mountain and road systems

M-series rear derailleurs are designed to work with 7, 8, and 9-speed Shimano-compatible mountain and road shifters. These Mezzo rear derailleurs are light, robust, and reliable. You can count on them to get any bike on the road. - Weight-saving aluminum bracket body and outer link - Steel pulley cage for extra chain-rub durability - Compatible with Shimano 7, 8, and 9-speed mountain and road systems