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How to Replace a Rear Derailleur on a Bike

Learn how to replace a rear derailleur from Silk Road Cycles' Brendon Nicholas in this Howcast bicycle repair and maintenance video.


Now we're going to talk about replacing your rear derailleur.

This is pretty simple.

You want to make sure you have the correct derailleur. Replacing it with the exact same derailleur is a good idea.

The reason you want to replace a derailleur is because it could be worn out. If you feel the back of the derailleur here and it shifts back and forth really easily, usually it means the rivets are worn out. You can always take it to your local bike shop and ask them to take a look at it to see if it's worn out.

To replace a derailleur is pretty simple.

First, you want to take your chain off so it's easy to get to the derailleur. The derailleur comes off really easily.

Then you want to pivot the derailleur back so the B screw is off your derailleur hanger.

Take your five millimeter wrench and unscrew it.

Then it's off. You can cut your cable off or undo your cable and just got off the tip.

Obviously, your chain will be gone so the derailleur will just be off.

To install a new derailleur, you've got to be sure that when you're putting it up to your derailleur hanger, it's going on straight and also it's not stripping any threads.

It's a lot easier without the change on and it's a lot easier without the cable on. If you do already have the chain and cable already on the derailleur, it's still pretty easy.

You are going to have to manipulate the derailleur so that the B screw is lining up with the spot where it rests right on the derailleur hanger. That ensures that the thread is going to be okay.

Also you want to grease the threads. Just like the threads on most bicycles, you want to grease them before you put them on.

I'm just making sure that it's going on nice and straight. Making sure it doesn't feel any resistance so I'm not cross threading it.

Then just tighten it down, making sure that B screw is above the derailleur hanger.

That's installing a rear derailleur.

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