Derailleur Arm – the arm which extends within the rear derailleur, with pulleys to feed the chain by. The derailleur arm is spring-loaded to get rid of slack from the chain when applying scaled-down gears. We're captivated with what we do, whether it's sharing our insider knowledge on terrific bikepacking https://bike-engine-process94814.onesmablog.com/an-unbiased-view-of-bike-engine-parts-75748540