Shimano Ultegra CN-M8100 12Speed 138L

Precision Linked.

The CN-M8100 features an extended inner plate design that provides superior chain retention on both the chainring and the cassette. This Dynamic Chain Engagement+ technology minimizes "pedaling shock" and chain noise, creating a ride feel that is noticeably smoother than standard 12Speed chains. With the extra length of 138L, this version is the ideal choice for long-travel enduro bikes, high-pivot suspension designs, or large-range gravel setups that require more chain than a standard road bike.

Why the CN-M8100 is the Performance Standard:

• HYPERGLIDE+ Technology: Designed to work perfectly with Shimano's 12Speed cassettes, allowing you to shift both up and down the block while maintaining constant pedaling pressure.

• SIL-TEC Surface Treatment: An advanced plating process using embedded fluorine particles. This ultra-low friction coating makes the chain run smoother, quieter, and significantly extends its lifespan in mud and grit.

• 138L Length: The extended length makes this SKU a "must-have" for e-MTBs and modern mountain bikes with long chainstays or high-pivot idler pulleys where a standard 126L chain just won't reach.

• Chromizing Treatment: The roller link pins are treated with chrome for maximum hardness and wear resistance, ensuring the chain maintains its precision index for thousands of kilometers.

• E-Bike Rated: Fully approved for the high-torque demands of Shimano STEPS and other mid-drive motor systems.

• Quick-Link Included: Comes with the SM-CN910-12 Quick-Link for fast, tool-free assembly (though we always recommend a master link tool for the easiest install).

Technical Specifications:

• Model: CN-M8100

• Series: Deore XT M8100 / Ultegra R8100

• Speeds: 12Speed

• Length: 138L

• Weight: ~252g (at 116 links)

• Treatment: SIL-TEC (Roller link) / Chromizing (Pin)

• Compatibility: Shimano 12Speed Drivetrains (MTB & Road)

The Alegro Perspective: This is the chain we keep in the workshop "for the big bikes." If you are building an e-bike or a long-travel 29er, the 138L version of the XT chain is your best friend. It offers the exact same shifting quality as XTR but with a focus on durability that makes it the smarter choice for daily training and aggressive trail riding. It’s the "sweet spot" of the Shimano range—unrivaled performance without the premium price of the flagship model.

Smooth Shifting. Enhanced Retention. Conquer Any Trail with Shimano XT.