Bike Derailleur Hangers

The rear derailleur hanger is a sacrificial component on your bike. It's designed to bend or break in order to prevent damage to the bike frame and drivetrain. Derailleur hangers can be re-aligned after a minimal crash, but often are replaced completely when bent. When riding road or mountain bikes it's always good to carry a replacement hanger just in case you need to swap one out mid-ride.