SHIMANO Derailer - Rear - Deore (model M591), black – Rivendell Bicycle Works
SHIMANO deore Bicycle Derailleur Bike Parts RD-M591 bicycle bike Riding Cycling MTB 9/27 Speed Bike Rear Derailleur - AliExpress Sports & Entertainment
SHIMANO Derailer - Rear - Deore (model M591), black – Rivendell Bicycle Works
Shimano Deore RD-M591 9 Speed Rear Derailleur | Jenson USA
Further tune or replace rear shimano derailleur RD-M591 : r/bikewrench