Amazon.com : SHIMANO RD-M591 Deore SGS Rear Derailleur (9-Speed, Long Cage, Black) : Rear Bike Derailleurs : Sports & Outdoors
Further tune or replace rear shimano derailleur RD-M591 : r/bikewrench
SHIMANO Derailer - Rear - Deore (model M591), black – Rivendell Bicycle Works
Sale on Shimano Deore RD-M591 SGS 9-Speed Rear Derailleur For All type of Bicycles, Mountain Bikes, Mountain Bicycles, Enduro, Gravel and Cross Bikes even eBikes