The Shimano XTR SM-CRM91 is a dedicated 1x11-speed single chainring engineered for XTR-level cross-country and trail performance. Designed specifically for the FC-M9000-1 and FC-M9020-1 cranksets, this 36T ring delivers confident chain retention on technical terrain through Shimano's Dynamic Chain Engagement+ narrow-wide tooth profile — without the weight of a chain guide.

Highlights

• Dynamic Chain Engagement+: Alternating narrow and wide teeth lock each chain link into place, dramatically reducing chain drop on rough and rooty terrain.
• XTR-grade construction: Anodised finish and premium-quality alloy deliver the durability and light weight expected from Shimano's flagship MTB groupset.
• 96mm BCD: Four-bolt 96mm bolt circle diameter matches FC-M9000-1 and FC-M9020-1 cranksets for a direct, tool-straightforward installation.
• 1x11-speed optimised: Tooth profile engineered for HG-X 11-speed chain compatibility, maximising shift feel and drivetrain efficiency.
• Clean 1x setup: Eliminates the need for a front derailleur and chain guide in most trail conditions, saving weight and reducing mechanical complexity.

XTR M9000 Drivetrain

The SM-CRM91 is a core component of Shimano's XTR M9000 drivetrain — Shimano's flagship mountain bike groupset, developed with World Cup XC racers. The 36T option suits riders who want a larger front gear for faster-rolling terrain or when running a tighter cassette range. It pairs with the full XTR M9000 11-speed rear drivetrain for a refined, race-ready 1x experience.

Compatibility & Fit

Designed for FC-M9000-1 and FC-M9020-1 cranksets (1x single-ring configuration). BCD: 96mm (4-bolt). Chain compatibility: Shimano HG-X 11-speed (10-speed chains also compatible). Speed: 1x11. Not compatible with double-ring (FC-M9000-2 / FC-M9020-2) crank arms — these use a different chainring interface. Bolt tightening torque: 8–10 N·m.