SRAM 11-12 Speed XD Freehub So, you're finally ready to step up and reap the benefits of SRAM's groundbreaking 11 and 12 speed drivetrains. Don't forget you'll have to switch to the XD driver, but don't worry, we've got you covered. This SRAM XD driver fits SRAM XO hubs, Roam 30 and Roam 40 wheels, and is only compatible with SRAM XD style cassettes. Features 4 pawl system for rapid engagement Alloy construction for lightweight Sealed bearings for long life | Sram | Xd Driver Freehub Body For X. 0 Hubs, Roam 30&40, Rail Xx&40