DT Swiss F 1900 Classic Rear Wheel - 27.5" 12 x 148mm 6-Bolt XD Ratchet LN 18 Black. F 1900 Classic wheels are made to withstand some of the harshest conditions. With a new rim based on the latest generation of Downhill rim design coupled with the tried-and-true ratchet hub the F 1900 wheel aims to take the beating of numerous bike park laps.