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

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 >>

12/27 Front derailleur shifting problem

Hi - my bike won't shift into the big chain ring up front when in the 4 or 5 biggest cogs in the back. In the smaller cogs in back, it shifts ok up front. Any thoughts or suggestions as to what's going on, and how to fix, would be greatly appreciated.

Thanks!... Read more >>

10/20 Chain sticks when pack pedaling

I just finished a complete overhaul if the bike. Everything was cleaned, bearings washed and packed in fresh grease.

When I went to live the chain, I noticed that back pedalling causes the chain to stick:

https://youtu.be/8NMFwxyvi8I

Any ideas?... Read more >>

08/19 When sitting and riding on mountain bike, front gears will not shift.

Hi, first post, very noobie to bike stuff sorry Smile
(Sorry, it's a little long, tried to keep it concise, sry).

Basically, when the bike is on a stand or even just picking the bike to rear tire is hovering, when pedaling and shifting through the front gears 1,2,3 it shits perfectly. Very smooth and fluid. However, when I'm riding the bike the bike gears will not shift at all!

(Quick necessary back story). Original issue was that the chain was rubbi... Read more >>

08/09 Shifting Problem

My front derailleur is a "Falcon" ---never heard of them! My problem is that I can shift to my large chainring or sprocket but as soon as I let go of the shift lever the derailleur pops the chain right back onto the small ring. W Thanks for your assistance.hen I move the shift lever it "clicks" several times---could there be some type of ratchet that is broken?... Read more >>

08/01 Front derailleur won't shift into third (largest) gear

I have recently been trying to teach myself more about bike maintenance by doing the work myself (I know horrible idea Smile ).  Recently I noticed that my chain was rubbing on my front derailleur so I went and altered the high/low screws on the derailleur.  Initially it wasn't moving when I was fiddling with the screws, and in an instructional video they suggested loosening the nut(bolt?) that holds down the shifting cable to allow the derailleur to reset to it's natural positio... Read more >>

07/17 Front derailleur can't shift from inner chainring to outer...sometimes

So I'm having a very strange problem. I have an old 10 speed Chimo with friction shifters on the stem. A few months back I noticed that when I downshift to the inner chainring, my front derailleur can't shift it back up to the outer chainring. I put it off and only used 5 gears till I tried to fix it today. I flipped the bike upside down and played around with it and it shifted perfectly back and forth. I then righted the bike and had someone hold up the back tire. It also shifted just fine. But when I rode it, once again it refused to shift back up to the outer chainring. Any ideas what this... Read more >>

06/09 Front derailleur drags on middle chainring?

Hi guys -- I'm new to the forum. Thanks for reading.

I'm fixing up a bike I've had for ~15 years that, sadly, I wasn't able to maintain. The bike is an 18-speed Royce Union mountain bike. Aside from new tubes/tires and a new chain, everything else is original (thumb shifters, both derailleurs are Shimano).

The original chain was just too rusted, so I replaced it, and it runs nicely now. Almost. It's fine on the granny chainring, and it's fine on the big ring, but when it's on the middle ring (the one that I tend to use the most), the chain drags across the inside... Read more >>

06/05 Rear derailleur rolling chain off

Hello I recently got my hands on a 99 trek 6000 and I have been working on it in my free time. When I try to ride it the back chain keeps going down in the gears until it pops off the gear on my wheel help!!... Read more >>

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How To Install a Rear Derailleur
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