The Specialized 21 Road Disc Thru Axle Derailleur Hanger is a precision replacement component designed specifically for Specialized Aethos frames equipped with disc brakes and rear thru-axle systems. This hanger provides the correct mounting interface for the rear derailleur, ensuring accurate alignment with the cassette for smooth, consistent shifting performance.

Derailleur hangers are intentionally engineered as sacrificial components, designed to bend or fail in the event of an impact to help protect the frame itself. Over time, or after a crash or drivetrain strike, a hanger can become misaligned, leading to poor shifting, noise, or accelerated drivetrain wear. Replacing a bent hanger with the correct model restores proper derailleur positioning and helps return shifting performance to factory standards.

Manufactured to match the Aethos frame’s disc brake and thru-axle architecture, this hanger installs cleanly and maintains the frame’s intended drivetrain geometry. Using the correct hanger is critical for modern 11- and 12-speed drivetrains, where even minor misalignment can affect shifting accuracy and reliability.... Read More