Shimano XT RD-M8100-GS Rear Derailleur - 12-Speed Medium Cage Black ModelNumber=33388 If you have a 50-55mm

If you have a 50-55mm stroke shock

Maxima 920 blended 15w reduces overall fork friction Steerer Type Tapered Lockout Switch Crown Brake Type Post Mount 200 Negative Spring Air Travel (mm) 170 Offset 44 Axle to Crown Length 586 Front Axle 15mm Thru x 110mm Maximum Tire Width 74

Front: Two tone injected high impact resistant plastic with engineering grade polymer struts

Forged aluminum construction is strong and keeps the cost low

Shimano XT RD-M8100-GS Rear Derailleur - 12-Speed Medium Cage Black ModelNumber=33388 If you have a 50-55mmDeore XT RD M8100 Rear DerailleurOffers fast and shockless shifting thanks to HYPERGLIDE+ technology The low profile design includes a bumper added to the derailleur pulley cage Shimano Shadow RD+ technology reduces chain slap and creates a quieter drivetrain Includes large 13t pulley Drivetrain is silent in all gear positions with decreased rear derailleur and chain tension in low gear Rear Derailleur Mount Type 10x1 Standard Rear Der Shifter