sram red d1 quarq road powermeter dub 170 48 35 yaw bb not includedX Range gearing technology gives you more range and a smoother gear progression, so you're always in the right gear Power meter is fully integrated into the chainring set for lighter weight Power readings are accurate within + 1. 5% and aren't affected by climate conditions during a ride Measures right and left leg power balance Improved front shifting performance for crisp and accurate front shifts Unique chainring shape results in a lighter weight,