45T Sprocket +18T XT/XTR [Shimano 1x11]

OneUp your Shimano 11 speed drivetrain with the new 45T sprocket for SLX/XT/XTR (M7000/M8000/M9000) Cassettes.

The 45T upgrade increases the stock Shimano 11 speed 11-40 cassette range by 12.5%. The 45T provides more total cassette range, it’s not just an easier granny gear. Adding the OneUp 45T sprocket lets you increase your 1x11 front chainring from a 30 to 34T without losing any low range. Eliminate dropped chains forever with our true Narrow Wide chainring design. 

Cassette Zones

The OneUp 45T tunes the cassette progression into two distinct zones optimized for climbing and descending.


(21-45T) 13-15% cassette progression. Smaller jumps to maintain an optimum even climbing cadence.

Descending (11-18T) 15-20% cassette progression. Larger jumps to reduce double tap shifting and provide faster burst acceleration when mainly pumping not spinning down trails.


  • 18T sprocket provides more even cassette progression for smoother cadence and improved shifting
  • Maintains the 40T as the smallest alloy sprocket for maximum cassette durability
  • Compatible with M9000/M8000/M7000 GS and SGS derailleurs
  • Compatible with standard freehub driver bodies  
  • 10 upshift points 
  • Patented (US 9,011,282) other patents pending



Cassette progression:  11-13-15-18-21-24-27-31-35-40-45 (11-40T)  or 11-13-15-18-21-24-28-32-37-42-45 (11-42T)

Sprocket material:   7075-T6 Aluminum (45T), Nickel plated hardened steel (18T)

Sprocket weight: 65g more than stock 11-40 cassette

Compatibility: For SLX/XT/XTR M7000/M8000/M9000 11-40T and 11-42T cassettes. 11 Speed only. Standard freehub driver.

Cassette range improvement:  12.5%

Color: Matched to XTR



Mount the OneUp 45T first and reinstall all sprockets except the stock 17T and 19T sprockets (these are replaced with our 18T and aluminum spacer). Due to the large pulley wheel offset of the latest 11 speed Shimano rear derailleurs, B-Screw adjustment is well within the normal operating range and chain wrap is excellent throughout the cassette for flawless wide range shifting. The conversion keeps the 40T as the smallest aluminum sprocket for maximum cassette durability.