Ten-speed drivetrains still outnumber 11 and 12-speed setups on the road, and SRAM's PC-1091R remains the performance chain for riders sticking with that generation of components. The R designation indicates this is the hollow-pin version, where SRAM machines material from the pin centers to reduce rotating weight without compromising the chain's load-bearing structure.

Chrome hardening on the pins and inner plates addresses the primary wear surfaces in any chain. Metal-to-metal contact between pins and bushings handles the majority of drivetrain friction, which is why SRAM focuses surface treatments here rather than on the outer plates where your eyes land but the physics don't. The treatment also provides corrosion resistance that keeps the chain running smooth through wet conditions and the occasional post-ride neglect.

Chain construction uses SRAM's solid plate design with chamfered edges on the outer plates for clean front shifting. The chamfers help the chain climb onto larger chainrings without hanging up during shifts, particularly noticeable when you're putting power down and ask the drivetrain to move to the big ring simultaneously. Inner plate geometry matches SRAM's 10-speed cassette tooth profiles, maintaining consistent engagement across the gear range.... Read More