|From this...to this. AtomicZombie shows you how to restore a typical derailleur.
A new tutorial for all of you bike hackers who recycle and reuse parts for your projects. This 10-part article includes step-by-step instructions, 53 high resolution photos and 13 High Definition (HD) videos to show you how to take apart and recondition a grungy derailleur using basic tools and methods. The tutorial also explains the difference between "hanger" and "frame mounted" derailleurs.
Here's an excerpt:
"The tension spring shown here, is wrapped around the main bolt, and it is responsible for the pulling back action that picks up the slack in the return chain. This will be one of the dirtiest parts of the derailleur, so give it a good wipe down with the degreasing agent and a rag. "
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