OneUp 45 Tooth Sprocket

Press Release
OneUp 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%. The 45T provides more total cassette range, it’s not just an easier granny gear. Adding the OneUp 45T sprocket lets you increase your 1×11 front chainring from a 30 to 34T without losing any low range. Eliminate dropped chains forever with our true Narrow Wide chainring design.

 

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.

 

Install
As easy as the original OneUp 42T. Remove stock 17 and 19 sprockets and replace with our 18 and 45. 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.

SPEC
Price: $90 USD
Material: 7075-T6 Aluminum (45T), Nickel plated hardened steel (18T)
Weight: 65g more than stock 11-40 cassette
Compatibility: For XT/XTR M8000/M9000 11-40T cassettes. 11 speed only. Standard freehub body.
Cassette progression: 11-13-15-18-21-24-27-31-35-40-45
Increased Range: 12.5%
Colour: Matched to XTR
US Patent 9,011,28

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If this is a good idea why didn’t Shimano do it?