important: Nuts and bolts on your bike should always be tightened to the manufacturer's specifications.

How to Install a Rear Derailleur

Removal and installation of a standard bolt-on rear derailleur.

In this tutorial we’ll learn how to replace a standard bolt-on rear derailleur.

Tools

For this job you’ll need a 5mm hex key for the derailleur’s mounting bolt, and a 2.5mm or 3mm hex key for the jockey wheels if you will not be removing the chain to clean or replace it. If you are removing the chain you may need a chain tool depending on your type of chain. You’ll also need wire cutters and a 9 or 10mm metric open end wrench, or a 5 or 6mm hex key to remove and install the rear shift cable. The last thing you’ll need is a phillips (+) screwdriver for adjusting the derailleur’s limit screws.

Rear Derailleur Removal

The first step is to shift your chain onto the smallest rear sprocket. Then pull off the shift cable’s end cap and loosen the cable pinch bolt. Remove the cable from the derailleur.

Now you’ll need to remove the chain from the derailleur. Some chains have a special connector pin that need replacing if removed, so if you don’t need to remove the chain for cleaning or replacement you can simply remove the lower jockey wheel and rotate the cage plate to release the chain. If you are removing the chain, disconnect a link and pull the chain through the jockey wheels.

Now you can unthread the derailleur’s mounting bolt all the way counter clockwise to remove the derailleur.

Rear Derailleur Installation

Before installing the new rear derailleur, apply some waterproof grease to the mounting bolt. Then thread it part way into the derailleur hanger, and rotate it clockwise to make sure the b-screw or tab is sitting behind the flat on the back of the hanger. Then fully tighten the mounting bolt.

If your chain is still on the bike, undo the bottom jockey wheel and thread the chain over the top pulley. Then re-install the lower jockey wheel. If you have removed the chain, re-route the chain through the jockey wheels and reconnect it. Search the site for tutorials on how to use a chain tool or a quick release chain link.

Rear Derailleur Set-up

Now preset the high-limit (H) screw so the upper jockey wheel is roughly in line with the smallest sprocket when viewed from behind.

Thread the shift cable back into the derailleur, pull it tight and tighten the anchor bolt so the cable flattens. Then find a bare stretch of cable and give it a good pull to make sure the cable is seated and has no slack. Then loosen the cable, pull it tight again and re-tighten it.

Now you’ll need to adjust the rear derailleur as shown in previous tutorials. If necessary, trim the cable so there is about 2 inches remaining. Then slide on a cable end cap and crimp it in place.

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Discuss this topic in the Derailleur Forums

I've tried searching for YouTube assistance but to no avail. Cycled to the shops this morning and the gears weren't functioning, had a look and something has gone horribly wrong. It's as though the chain is suddenly inches longer than it should be and it isn't holding any tension unless the derailleur sits all the way back (image attached) almost so the chain is touching itself as it travels throu...

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I've got a problem with the front derailleur on my 21 speed mountain bike. The bikes chain keeps moving to gear one or even slipping off the chain entirely on the front when I try to ride it. I use this bike to get around my college campus, so I use this bike every day, so I need this bike to work. The bike in question is a 1996 Marin bolinas ridge mountain bike I got at a garage sale years ago ...

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I'm brand new to bike maintenance, and I have incredible difficulty getting my front derailleur to shift into the third (highest) gear, and then staying there. I don't know if the problem is with the shifter or the derailleur, and I would really appreciate any help. derailleur: shimano (that's all I know about it) shifter: a cheapy gradient thumb-knob shifter. No clicks, no numbers, just a - and...

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where to start?

posted 1 year ago

Bought a bike from our neighbor for my husband, 1990ish Schwinn Woodland. When he tried to ride it, realized it doesn't shift gears at all. Where do we start to look at what could be wrong?...

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I fell from my bike at quite the speed, I got injured pretty badly and this happened to my bike as well, is there a way to fix this or do I need to replace https://imgur.com/a/xlGbC...

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Locked up Shimano SG-7C18

posted 1 year ago

Hi. I just bought a used bike and had to change the inner tube in the back wheel. Putting the wheel back on I forgot to reattach the brake arm. I jumped on the bike and almost immediately the wheel locked up. I've taken everything apart and put it back together again, but the wheel just won't move. Does anyone know what I messed up here?...

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This concerns a Shimano Tiagra 4600 2x shifter. There is travel remaining in the rear deraileur, but none in the shifter itself. I can't reach the two biggest cogs using either of the front chainrings. I did dump the bike, albeit not hard. However, that accident caused the shifter housing to become out of line with the handlebars. I suspect either my repair efforts or the crash have damaged t...

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MTB Ghost Shifting fix

posted 1 year ago

First bike in 7 years and I'm recently experiencing Ghost shifting, I know little to nothing about repairing bikes and I'm in need of help of how to stop the bike from shifting on its own it is very frustrating and makes it difficult to ride at times...

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I have vintage Charger brand gear levers and I am wondering if they'll work with Suntour VX derailleur as well as derailleurs that say index system....

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From 1st to 2nd-problem

posted 1 year ago

Hi. Sorry I dont know if this is in the right section of the forum. I just got a mtb for the 1st time as an adult. On the left hand side of the handle bars where you can change for 1 to 2 to 3. When I change from 1 to 2 it doesnt alwaya do it. The dial moves to 2 but the bike makes an awful noise and no matter how much i pedel it still makes that noise. If I then go into 3 it then after a good ...

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I am riding a Bianchi 928 with SRAM Red components.  I have a 10 speed 11x28 cassette.  I am replacing my rear derailleur since the guide pulley cogs are now worn to sharp points.  The present derailleur has a short arm.  SRAM seems to have 3 sizes of derailleur arms for a 10 speed cassette; short, medium, and long.  The 28 cog gear still works will with my short derailleur.  I heard that yo...

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I have a Deore LX shifter like on this photo The push button at the bottom doesn't catch the piece inside unless I press slightly up when I shift. Is that fixable or do I have to change the part? Thanks!...

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Yesterday 5 meters away from my destination my rear derailleur suddenly "snapped". I though at first that the cable broke, but no. I flipped the bike around and started shifting and it looks like it kinda "works" but it suddenly doesn't want to shift into the lowest gear (the biggest gearsprocket). I rode back home just fine, but I am a little bit worried and I am not sure what happened. It is a ...

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Trouble fixing gears

posted 2 years ago

Hey, i hope this is the correct subforum The bike gear cables broke and Im trying to replace them. BUt it's my first time, and I've run into some trouble. I can't seem to get the correct tension in the cable, or there's something wrong with the thing thats supposed to shift gears. I took a video of it. The same tension works for two different positions in the gear shifter thing. How do I fix this...

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I have a problem on my Front bicycle derailleur. I'm new to bike repair so I'm not sure of using the right terms. The chain is on the largest chainring in the front and when I use the small pusher on my shifter, I can hear a click but the chain doesn't move to a smaller chainring. I read online some advices and I removed the cover of my shifter, I put WD40 first, waited a long time, then put tri...

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