How To Replace a bicycle rear derailleur hanger

Last Updated on August 7, 2021 by FAB Jim The Cyclist

Is your mountain bike not shifting well after a crash?  Can you see your derailleur is at a weird angle?  Does it look like this?

Rear Derailleur Hanger Bent

There is an easy fix.  Most modern mountain bikes have a removeable derailleur hanger that saves the frame in the result of a crash.  I may have had a crash with mine and as you can see above the hanger is quite bent and shifting isn’t good.  So, what you need to do is replace the hanger.  This is what a typical hanger looks like:

Rear Derailleur Hanger

Here is a look at just how bent mine was compared to the new hanger:

Left one is the new part

This site is good for finding the correct hanger:

Just enter your bike details and it should lead you to the correct hanger.  They are rather expensive for a small piece of aluminum, but better than frame damage.  And sometimes you can find them for cheaper if you shop around.

Step 1 Remove Tire

Open brake and remove tire.  If you need help with this step check out our post for changing a tire:

How to change a mountain bike tire with an inner tube and V-brakes

Step 2 Remove Derailleur

Use an allen wrench and remove the rear derailleur and let it hang on the chain.

Remove Derailleur

Step 3 Remove Old Hanger

Remove the old derailleur hanger.  Most I have changed just require one allen bolt removal, but there are different kinds.

Rear Derailleur Hanger Removal

Step 4 Clean Frame and Grease

Clean the frame surface and add some grease to the contact area.

Clean and grease contact area

Step 5 Install New Hanger

Install the new hanger on the frame, be sure to grease the threads.  Most are just held in with a bolt like this:


I tighten it rather firmly.  You don’t want it to come loose or be impossible to remove if you need to replace.


Step 6 Put Everything Back Together

Follow the above in reverse to put everything back together.  It should be straight and nicely aligned like this when done:


Published by FAB Jim The Cyclist

Jim has over 40 years of experience with bicycles and loves road and mountain biking and just going for calm cruises. He is a mechanic who has built custom bikes and is also very interested in bike history.

6 thoughts on “How To Replace a bicycle rear derailleur hanger

Leave a Reply

%d bloggers like this: