Sprint-worthy stiffness meets climb-friendly weight in SRAM's RED Crankset. Advanced analysis of pedaling forces has yielded a hollow construction design that incorporates an integrated, four-arm spider and larger crank arms to achieve the lofty weight and strength goals. Together with X Glide R chainrings and a RED front derailleur (sold separately), your front shifting will receive a major boost in speed, efficiency, and simplicity. SRAM's new X Glide R chainrings start out as 5mm-thick aluminium plates which are precision machined to eliminate all unessential material while retaining extreme stiffness to provide fast, crisp shifting. And SRAM didn't stop there; plenty of attention was given to the placement of the shift pins and ramps, which are optimized to coordinate your shifts with your natural cadence.