SRAM's renowned X0 Rear Derailleur is a serious rider's and racer's dream. Expertly crafted with a full carbon cage, and a titanium main spring, the X0 is light enough to grace the winningest bikes out there. It's renowned for its precise, consistent function, efficient 1:1 actuation ratio and SRAM's Direct Route cable technology, all of which ensure that every single shift is crisp and lightning-fast. Plus, with sealed bearings, this sweet changer is built to last, too.
An important part of a rear derailleur's job is keeping the chain taut as you change gears. Chain-wrap capacity is a number that tells whether or not a derailleur will be able to do this on the drivetrain you plan to use it on. Calculate chain-wrap capacity with this formula: Chain-wrap capacity = (large chainring - small chainring) + (large rear cog - small rear cog). Example: 44/29 chainrings and a 11-28 cassette: (44 - 29 = 15) + (28 - 11 = 17) = 32-tooth chain-wrap capacity.