SRAM's X0 Hub offers lightweight, reliable performance. Ultra-durable, high-precision Speedball bearings spin smoothly in all conditions, and the tapered aluminum axle provides strength with minimal weight. This hub devours techy sections with it's super-smooth 6.9-degree engagement Double Time ratchet system. It accommodates standard 6-bolt rotors and comes with 12mm through-axle end caps and a 9mm quick release, so you can customize it to fit your ride.