The stunning X Glide R™ chainrings are optimized for use with the YAW™ Technology in the front derailleur, delivering seamless, flawless performance. X-GlideR Chainrings The chainrings are designed for an optimized shifting performance with the Yaw front derailleur. The stiffer rings (5mm 7075-T6 aluminum CNC-machined) feature upshift rivets with an advanced design adopted from SRAM XX. CNC machining allows for precision control of each tooth shape, ramp, and nearly every shifting feature of the chainring. Chainrings, chain, and front derailleur are designed as a single integrated system for optimized performance. BB30 Besides serious weight savings, this bottom bracket means narrow Q-factor, more ankle clearance, greater bearing durability and stronger crank construction.