Following in the footsteps of Shimano XTR M9100 12-speed, the XT M8100 series moves to a direct mount crank arm/chainring system. The XT SM-CRM85 was developed for the M8100/8120 series XT 1x (single ring) Crank Arm sets for the 12-speed drivetrain. It is compatible with the Shimano CN-M9100/8100 12-Speed Chain. The sandwich construction of CFRP and aluminum spider features a bolted ring, and the assembly is a direct mount design that offers incredible stiffness and pedaling efficiency, with a simple and solid mounting set-up. Shimano developed their Dynamic Chain Engagement+ tooth profiling system for use in 12-speed single-chainring configurations for XC, Enduro, and trail riding.

No company holds more chainring and drivetrain patents than Shimano and the engineering behind the DCE+ system delivers more chain retention and smoother pedaling - even over the most technical terrain. Proper chain retention in conjunction with the adjustable chain stabilzer of the Shadow RD+ rear derailleur with any gear combination will also reduce abrasion and wear. DCE+ eschews the narrow-wide principle used by other brands, but a keen eye will see the alternating flat edge, rounded edge tips of the teeth, and other subtle machining of the full tooth to enhance engagement and smooth action.

Shimano offers this chainring in 28, 32, 34, 36 tooth options. All are compatible with the M8100/M8120 - 1x model crank arm sets. The ring is affixed to the spline of the direct mount receiver of the driveside crankarm, via a lockring that comes with the crankset. The tool for mounting is the Shimano TL-FC41, which is sold aftermarket, but is also included with crankarm sets in the initial release window. Note that the 1x ring has