Sram Red 1 Axs, Crankset, Speed: 12, Spindle: 28.99Mm, Bcd: Direct Mount Road* Single ring drivetrain simplifies functionality and reduces weight* 48 and 50t variants feature direct mount aero chainrings for better aerodynamics* Non aero chainrings can be installed with a single tool, making gearing changes a breeze* SRAM X SYNC wide tooth, narrow tooth chainring technology provides maximum chain control* Laser etched chainring finish is more durable* DUB bottom bracket adds durability and simplicity* Can be upgraded to a