Why Choose the Shimano Alivio RD-M3100 for Your 9-Speed MTB Build?

The Shimano Alivio RD-M3100 is a capable 9-speed MTB rear derailleur that brings Shadow RD low-profile design to an accessible price point, keeping the mechanism protected from trail obstacles while reducing chain slap and improving chain retention on rough terrain. The long SGS cage handles cassettes up to 36t with 45t total capacity, giving riders ample range for varied terrain without needing a clutch system -- Shadow RD's compact form factor reduces the risk of damage from impacts without adding the weight or engagement resistance of an active clutch mechanism.

Compatible with Shimano 9-speed road and mountain shifters. Fits both Shimano Rear Direct Mount and standard 10x1 dropout hanger frames. MPN: ERDM3100SGS. A reliable, straightforward 9-speed rear derailleur for trail, cross-country, and recreational MTB builds.