Hear the wind rushing past, the crunch of knobbies biting into dirt and the buzz of your freehub with SRAM's X9 Rear Derailleur. SRAM's Type 2 technology eliminates chainslap, derailleur bounce, and other drivetrain racket. The roller bearing clutch keeps the chain tensioned for consistent shifting and is virtually maintenance free. The tech continues with an aluminum/composite construction, SRAM's 1:1 actuation ratio and direct cable routing for quick, reliable shifts. Plus, the Cage Lock feature gives you super easy rear wheel removal and installation.