How to Install a Rear Derailleur
Removal and installation of a standard bolt-on rear derailleur.
- How to Adjust Your Rear Derailleur
- How to Align a Rear Derailleur Hanger
- How to Overhaul a Jockey Wheel
- How to Replace an Inner Shift Cable
- How To Install a Front Derailleur
In this tutorial we’ll learn how to replace a standard bolt-on rear derailleur.
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.
- Park Tool HXS-1.2 Hex Wrench Set
- Park Tool Wrench Combo Set
- Park Tool SD-Set Shop Screwdrivers
- Shimano TL-CT10 Cable Cutter
- Park Tool SK-3 Starter Mechanic Tool Kit
- Park Tool PK-3 Professional Tool Kit
Discuss this topic in the Derailleur Forums
Hi everyone,Ive got a 2nd hand marin bobtail trail. I get it indexing up nicely,wont go down well. cables,hanger seemed ok,derailleu not bent but a bit worn an sloppy,so i replaced it. bought a nice deore m592 shadow on ebay.i didnt need a long cage but it was a good price. At first it seemed fine. now after a few months an cpl months not using ,its doing it again.Its all lined up straight.ive jus...Read more
Hi All, First post on this forum. Simple question - there are various models of Shimano Revoshft shifters- RS35; RS41; RS45; RS47. As I need to replace one of these, as long as the gear number matches - are they all compatible? Phil...Read more
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...Read more
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 ...Read more
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...Read more
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
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
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
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...Read more
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
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
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 ...Read more
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...Read more
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
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 ...Read more