SRAM SX Eagle Rear Derailleur - 12-Speed Long Cage Aluminum Black B1

This 12-speed rear derailleur from SRAM, the SX Eagle (RD-SX-1-B1), long cage, gives entry-level trail and cross-country riders a wide-range 1x12 drivetrain at an accessible tier. X-Actuation with X-HORIZON geometry keeps shifts crisp and holds the cage steady against chain slap.

A Roller Bearing Clutch manages chain tension over rough ground to cut dropped chains and noise. The long cage supports 10-50t and 11-50t cassettes with a 40-tooth total capacity, handling a 50-tooth max cog, and it mounts to a standard 10x1 hanger. Aluminum construction keeps it durable on the trail.

As the SX tier at the base of the Eagle line, it brings 12-speed range and clutch tension to riders building or upgrading an affordable 1x setup.