One of the more useful things about Shimano's 12-speed ecosystem is that the same chain runs on your road bike and your trail bike. The CN-M7100 is the SLX/105-tier Hyperglide+ chain, and it works across the full 12-speed Shimano range—105 R7100 mechanical or Di2 on the road, SLX M7100 on the mountain side, and everything in between. If you keep a road bike and a mountain bike in the garage, stocking one chain covers both.

The engineering that makes Hyperglide+ shift the way it does lives largely in the chain. Extended portions on the inner plate ends grip cog and chainring teeth more securely than previous-generation chains, which is what lets the drivetrain shift under load without the pedaling shock or noise you'd get from an older 11-speed setup. The plates work in concert with the ramp and tooth profiles on Hyperglide+ cassettes and chainrings, so shift quality depends on running the matched components together rather than mixing chain generations.

SIL-TEC surface treatment covers the roller link plates, which is Shimano's fluorine-embedded low-friction plating. On the road it means slightly less drivetrain drag; off-road it means the chain holds up better to grit and repeated washing. The chain ships with a single-use Quick Link—install it once, and if you need to break the chain later for cleaning, use a fresh link rather than reusing the original. A pair of TL-CN10 pliers makes installation and removal considerably easier than trying to muscle the link by hand.... Read More