High-pivot suspension designs and long-chainstay frames need more chain than standard lengths provide, which is why Shimano offers the CN-M8100 in this 138-link version. If you've ever sized a chain for a modern enduro bike or a mullet conversion and found yourself uncomfortably close to the minimum after removing links, the extended length solves that problem. You get the extra material needed for proper sizing without having to buy two chains and splice them together.

The CN-M8100 works across Shimano's entire 12-speed ecosystem. Originally developed for the Deore XT mountain bike groupset, it's also the OEM chain for 12-speed Ultegra road and GRX gravel drivetrains. That cross-compatibility means you can stock one chain model for your mountain, road, and gravel bikes if they're all running Shimano 12-speed. The plate profiles and tooth engagement geometry match the Hyperglide+ cassette cogs and Dynamic Chain Engagement chainring teeth used across all these systems.

Hyperglide+ represents Shimano's current shifting technology, and it requires specific chain geometry to work properly. The CN-M8100 features extended inner plates that engage more deeply with the chainring teeth, improving chain retention during rough terrain and reducing the vibration that occurs as plates roll onto and off the chainring profile. That deeper engagement translates to quieter pedaling and more secure chain behavior when you're hammering through rock gardens or accelerating out of corners. Shimano claims shifting speed improved by about a third compared to the previous Hyperglide standard, and the difference is noticeable when you're shifting under load.... Read More