OneUp Components Shimano XTR/XT Expander SprocketUpgrade your Shimano 11 speed drivetrain with the new 45T sprocket for XT/XTR (M8000/M9000) cassettes. The 45T upgrade increases the stock Shimano 11 speed 11-40 cassette range by 12 5% and provides more total cassette range 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 OneUp's Narrow Wide chainring design The OneUp 45T tunes the cassette progression into two distinct zones, optimised for climbing and descending Climbing: (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 OneUp Components is a small team of passionate mountain bikers, dedicated to bringing genuine value to the MTB market. OneUp was founded by three former Race Face engineers, Chris, John and Sam. Together they have over 22 years of bike industry experience and have developed some of mountain biking's most recognisable and award winning products Features: 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 GS and SGS derailleurs Compatible with standard freehub driver bodies 10 upshift points Technical Data: Cassette progression: 11-13-15-18-21-24-27-31-35-40-45 Sprocket material: 7075-T6 aluminium (45T), nickel plated hardened steel (18T) Sprocket weight: 65g more than stock 11-40 cassette Compatibility: For XT/XTR M8000/M9000 11-40T cassettes (NOT compatible with 11-42T), 11 speed only, standard freehub driver Cassette range improvement: 12 5% Buy OneUp Components from Chain Reaction Cycles, the World's Largest Online Bike Store.