Upgrade your drivetrain with the Shimano XTR M9100 12-speed Upgrade Kit, designed for high-performance mountain biking. The RD-M9100 Rear Derailleur delivers precise, reliable shifting and accommodates cassettes with up to 51 teeth. The cassette features Rider Tuned gear steps, offering optimal cadence control across varied trail conditions. With RapidFire Plus technology, the shift lever enables quick, responsive gear changes. Paired with the M9100 chain, this kit ensures smooth and consistent shifting on every ride. XTR M9100 Upgrade Kit Includes Shimano CS-M9101 Cassette Cassette Cogs: 10-45t:10-12-14-16-18-21-24-28-32-36-40-45t Cassette Cogs: 10-51t: 10-12-14-16-18-21-24-28-33-39-45-51 Finish: Anodized Compatible Freehub: Shimano Microspline Shimano RD-M9100 Rear Derailleur Cage Length: GS/Medium, SGS/Long Max Low Sprocket: 45t (GS), 51t (SGS) Pulley size: 13t Shimano SL-M9100 Shift Lever Mount: 22.2mm clamp or I-Spec EV Max multiple shifts: 4 Shifter type: Rapidfire Plus Included Derailleur Cable: Optislick Shimano CN-M9100 Chain Number of links: 126 Quick link included (SM-CN910-12)