FSA K-Force WE Rear Derailleur 11-Speed Short Cage Electronic Shifting – BLKFSA (Full Speed Ahead) K Force WE Rear Derailleur 11 Speed Short Cage Black. The K Force WE Rear Derailleur is part of an 11 speed system that works together with the WE shifters to maintain precise shifting accuracy for a smooth ride. 11 speed system with 30T total capacity maximum cog size 32T Composite pullys offer low friction energy saving properties Single arm contruction with timing gear Electronically driven gearbox moves the cage precisely