The new 10 speed X.9 rear derailleur has received more than just a colour change. The biggest difference when riding is the addition of SRAM’s Exact Actuation technology. When combined SRAM shifters with the same feature, Exact Actuation is the evolution of SRAM’s 1:1 Actuation Ratio. Essentially, how far you move the shifter is how far you move the derailleur so gear changes are instant, set up is easy and the system stays correctly adjusted for longer.
Compared to X.0, the medium (2x10) and long (3x10) cage versions use alloy cages while only the short cage runs carbon fibre and the pulley wheels spin on sealed bushings rather than bearings. Other than that the design is very similar, using the same direct cable path to reduce friction in the cable, making for easier gear changes.
Manufacturer's Description
SRAM X9 Rear Mech 10sp
SRAM Exact Actuation for precise and dependable 10-speed performance. Carbon and alloy cage makes it light and tough - 204 grams for medium cage. 3 cage lengths available - Short for DH, Medium for 2X10 and Long for 3X10.
Direct Route Technology:
Here's the dirt on middlemen: they suck. That's why Direct Route Technology™ doesn't have one. Instead, the cable routes directly to the actuation mechanism. Result? Less friction. Less effort. More oomph. Plus it's impervious to cable housing damage. Nice.
Exact Actuation:
When we launched our road technology from scratch we reapplied our MTB proven SRAM 1:1 actuation ratio (shifter cable travel : derailleur movement) for 10 speed rear shifting. EA helps to simplify/stabilize the uneasy act of balancing rear derailleur hanger design, tight cog spacing and exact cable tension. The result: the easiest index shifting system to set up and it stays that way.
