Shimano

XTR FH-M9111-B Rear Centerlock Hub

Shimano's XTR group has a long history of success at the highest levels of competitive mountain biking, and after 27 years of development, Shimano continues that winning pedigree with the all-new XTR FH-M9111-B Rear Hub. Made with precision using the lightest and strongest materials in Shimano's lineup, this flagship rear hub offers impressive stiffness, low-rolling resistance, and the longevity you've come to expect from XTR—all at a very low weight. It's compatible with the new XTR 12 and 11-speed Micro Spline cassettes, and features Shimano's renowned silent coasting matched with quick accelerations that help you channel all of your focus to the trail ahead.

For the XTR M9100 group and the XTR rear hub, Shimano designed a new freehub body dubbed Micro Spline. Micro Spline allowed them to move from an 11t to a 10t small cog on their cassettes while adding a 12th gear, increasing the gear range to a whopping 510% on their wide-range 12-speed cassette. The Micro Spline freehub body is made of aluminum instead of steel, saving weight while actually improving durability as the smaller and more numerous splines are designed to distribute force more evenly over a greater area, preventing the cassette from eating into the freehub body. The design also allows for larger-diameter axles inside the hub, boosting lateral stiffness. In addition, the updated XTR hubs still maintain the nearly silent coasting performance we all know and love, which lets you hear how much traction your tires have at all times, dispelling the notion that loud buzzing equals high-performance.

Finally, the XTR rear hub uses cup and cone bearings that are serviceable. That's definitely something you'll want to do on occasion in order to keep them running in top shape. After all, they're a lightweight, race-tuned set of bearings, which means they're capable of operating at levels that other bearings can only dream of.