The Sram X9 10-speed rear derailleur is designed for 10-speed systems only. It features aluminum alloy links and forged B-knuckle as well as a high strength Grilon® P-knuckle for durability.
Direct route technology means the cable is routed directly into the derailleur instead of through a loop of cable housing. This means snappier shifts with less friction and less shifting force. Exact actuation shifting balances rear derailleur hanger design, tight cog spacing and exact cable tension to create a system that is easy to adjust and holds its adjustment.
The X9 10-Speed rear derailleur comes in three cage lengths. The short cage has a 55mm carbon/alloy cage and is intended for downhill. The medium 75mm cage works optimally with 2x10 systems and the long 99mm cage is for 3x10 systems. Get the long cage if you are undecided. Select cage length and color.