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Shimano XT FC-M8000-B1 Boost 170mm Crank Arm


The 1-speed crank is Shimano’s driving efficiency MTB gear range ever and with one ring up front, rhythm is optimized. B-Version with 3 mm outboard chain line.

Following mountain biking’s evolutionary path, Shimano DEORE XT M8000 delivers the 11-speed features and premium performance found on the top-of-the-range XTR-level components, elevating the performance of enduro and cross country riders on demanding trails or race circuits.

Now 11-speed, new DEORE XT M8000 brings powerful, dynamic performance that establishes a new benchmark for mountain bike excellence. With DYNA-SYS11 Shimano encourages modern mountain bikers to ride anywhere with its advanced gearing concept that helps maintain rider efficiency. Designed with both XC and aggressive trail riders in mind, DYNA-SYS11 brings enduring performance thanks to smart materials and enhanced drivetrain stability due to new derailleur and chainring designs.

Like its XTR sibling, DEORE XT M8000 offers 1×11, 2×11, and 3×11 crank options to satisfy any type of rider ability level or terrain. New 2×11 and 3×11 M8000 drivetrains, expand range while maintaining even better rhythm when paired with an 11-40T cassette for optimized cadence control. An exciting addition for DEORE XT M8000 is a 1×11 specific 11-42T cassette that expands Shimano’s 1×11 gear range slightly over the race inspired 11-40T of XTR.

Reduced capacity for dropped chains – The 1×11 tooth profile on the XTR and new DEORE XT chainsets combine wide steel teeth shape with special hooked teeth design for lasting chain retention especially over uneven terrain. These improvements increase chain retention force by 150%, increasing chain life and drastically reducing the possibility of a dropped chain.

The real advantage of 11-speed is the ability to have all the range you require without sacrificing the rhythm you need.


  1. Most advanced mountain bike chainrings ever produced
  2. 3D hollow structure increases stiffness
  3. Carbon/aluminum construction
  4. 1x with proprietary chain retention technology
  5. B-Version with 3 mm outboard chain line
  6. Available chainrings in 30T, 32T, 34T. (Chainring not included!)

Product features

  1. Use: MTB
  2. Group: XT
  3. Model: FC-M8000-B1 (B-Version with 3 mm outboard chain line)
  4. Gradation: Chainring not included!
  5. Crank Arm Length: 170mm
  6. Q-Factor: 176mm
  7. Threaded BB shell width: 68 / 73mm
  8. Gear: 11-speed
  9. Construction: Hollowtech II
  10. Compatible Chain: HG-X 11-speed
  11. PCD: 96mm
  12. Chain line: 53.4mm
  13. Weight: 598g (without chainring)


  1. Crank arm: Aluminum Anodized
  2. Crank axle: Steel Plated
  3. Spider arm: Aluminum Painted