The Shimano Deore XT CS-M8100 brings XTR-derived HYPERGLIDE+ shifting technology to trail-focused mountain bikers. With a 12-speed spread and Micro Spline freehub compatibility, it delivers fast, precise gear changes under load — ideal for demanding singletrack where you can't always pick your moment to shift.

Highlights

  • HYPERGLIDE+ shifting: Specially profiled teeth allow smooth, accurate upshifts and downshifts even when pedalling hard under load.
  • Micro Spline freehub: Shimano's 10-tooth-compatible interface uses a finer, more widely distributed spline pattern to reduce freehub body wear and save weight.
  • Wide gear range: The 10-51T option delivers a 510% range for steep climbs without sacrificing a tight-ratio top end; the 10-45T suits riders who prioritise on-trail cadence control.
  • Beam Spider construction: A stiff aluminium spider links the upper cog cluster, reducing cassette inertia and keeping weight low without compromising durability.
  • Mixed material build: Sprockets 1–10 are steel for long wear life; sprockets 11 and 12 are anodised aluminium to trim grams where load is lowest.
  • 55mm chain line: Optimised chain line improves compatibility with a wider range of modern MTB frames.

Construction & Design

The CS-M8100 uses a BEAM SPIDER — an aluminium sub-assembly that groups the upper sprockets onto a shared carrier. This reduces the total number of individual components, stiffens the cluster under pedalling load, and brings cassette inertia down so acceleration feels snappier. The lower, higher-load sprockets are made from steel for durability, while the two lightest-load cogs at the top of the range are anodised aluminium.

Compatibility & Fit

Requires a Shimano Micro Spline freehub body — not compatible with standard HG or XD freehubs. Designed for 12-speed Shimano MTB drivetrains (Deore XT M8100, XTR M9100, Deore M6100, SLX M7100 series). Pair with a Shimano 12-speed chain (e.g. CN-M9100, CN-M8100, CN-M7100). Optimised for a 55mm chain line. Available in two sprocket configurations: 10-45T (cogs: 10-12-14-16-18-21-24-28-32-36-40-45) and 10-51T (cogs: 10-12-14-16-18-21-24-28-33-39-45-51).

Shimano offers a limited warranty covering defects in materials and workmanship. For warranty support, return the item to Tune Cycles.
  • HYPERGLIDE+ tooth profile enables smooth, reliable shifts under pedalling load
  • Micro Spline freehub interface — supports a 10-tooth smallest sprocket for a tighter gear spread at the top end
  • Available in 10-45T and 10-51T for trail and enduro applications
  • BEAM SPIDER aluminium sub-assembly reduces cassette inertia and weight
  • Steel sprockets (cogs 1–10) for long-lasting wear resistance
  • Anodised aluminium top cogs (11–12) for reduced weight
  • 55mm chain line optimised for modern MTB frame compatibility
  • Part of the Shimano Deore XT M8100 12-speed groupset
SeriesDeore XT M8100
Speeds12-speed
Sprocket options10-45T / 10-51T
Sprocket ratios (10-45T)10-12-14-16-18-21-24-28-32-36-40-45
Sprocket ratios (10-51T)10-12-14-16-18-21-24-28-33-39-45-51
Weight (10-45T)461 g
Weight (10-51T)470 g
Freehub compatibilityShimano Micro Spline
Chain line55 mm
Sprocket material (cogs 1–10)Steel
Sprocket material (cogs 11–12)Anodised aluminium
Spider materialAluminium (painted)
TechnologyHYPERGLIDE+, BEAM SPIDER
SKU SHM-CS-M8100
Barcode # 4550170443849
Brand Shimano
Shipping Weight 0.3000kg
Shipping Cubic 0.001000000m3
Unit Of Measure each

Must be installed and serviced by qualified bicycle mechanic

Related products

More From This Category