The sram x01 drivetrain carries on the tradition of srams championship winning 1x philosophyall the way down the mountain the setup is simpler the drivetrain is lighter and the shifting is fast and solid bottom line x01 is the right one for any terrain every time x dome x dome technology creates an incredibly lightweight precise and strong cassette the open design aids in mud clearance giving you cleaner shifting performance and longer component life xd driver body xd is a new cass