49. How To Install a Rear Derailleur

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

IMPORTANT: Nuts and bolts on your bike should always be tightened to the manufacturer's specifications.
How To Install a Rear Derailleur
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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.

Tags

Discuss this topic in the Derailleur Forums

06/06 Help.. Rear derailleur wrong position?

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 through. Is this an easy fix or will it need replacing?
[Image: IMG_20180606_193734.jpg]... Read more >>

10/09 Problem with my Front Derailleur on my Bike

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 for $25. The bike has been working great so far, except for today.

After doing some research my bike uses a Shimano atlus bottom bracket Front derailleur. I think I figu... Read more >>

10/06 Front Derailleur/Shifter Problem

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 +
[EDIT: after some further reading, I discovered the more accurate term is "friction" shifter.]

Problem: as I move the shifter up, it becomes increasingly stiff... Read more >>

10/03 where to start?

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?... Read more >>

09/29 My derailleur is out of place

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... Read more >>

09/24 Locked up Shimano SG-7C18

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?... Read more >>

09/09 How would I know if my shifter is broken

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 the shifter.

The crash did bend the rear deraileur, but that has since been replaced and aligned.

Thanks,

Chip... Read more >>

08/26 MTB Ghost Shifting fix

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... Read more >>

07/16 Will Charger Brand Levers Work With Suntour Vx Derailleur?

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.... Read more >>

07/02 From 1st to 2nd-problem

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 few seconds it eventually corrects itself and stops making then noise and changes correctly.

On the right hand side of the bike, the numbers all go up and down no ... Read more >>

06/28 SRAM rear derailleur arm length

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 you need a longer arm if you have a bigger gear but I am not sure if that is true or not.  Is there any reason I should not replace my short arm derailleur with a medium length arm?  Are there advanta... Read more >>

06/23 Repairable Deore LX shifter?

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!... Read more >>

05/18 Road Bike Rear Derailleur Problem

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 Shimano RD 2300, I tried to find a replacement but I think it is pretty much sold out. I tried to look for other Shimano 2x8 rear derailleurs, and I found these:
Read more >>

03/18 Trouble fixing gears

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?



... Read more >>

03/13 Problem with Deore DX Shifter

[Image: IMG_20170205_162903.jpg]
[Image: IMG_20170303_103150.jpg]
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... Read more >>

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