1. How to Adjust Your Rear Derailleur
Applies to most 3-chainring derailleur systems. Adjust your Front Derailer
Adjusting your rear derailleur can be frustrating. I’m hoping that this tutorial will help you understand how each component of your derailleur works, and how to set up and adjust it properly. Once your derailleur is set up correctly, most future adjustments can be done by hand. Let’s get started!
Almost all modern derailleurs function the same basic way. They are designed to move (or derail) the chain from one sprocket to the next. The upper guide pulley (or jockey pulley) moves the chain in both directions. For instance, when you want to climb a hill, you shift down to a lower gear. This pulls the shift cable and forces the guide pulley to change to a bigger sprocket. When you want to go faster, you adjust the shifter to a higher gear. This releases shift cable tension and allows the derailleur springs to pull the guide pulley back down to a smaller gear. Each time you shift gears, the length of chain changes. The lower tension pulley is spring-loaded to take up this slack.
There are 3 adjustment screws – the B-Screw (B-tension adjustment), the H-Screw (high gear limit stop) and the L-Screw (low gear limit stop). Adjustments on these screws should always be made in 1/4 turn increments.
The B-Screw controls the derailleur body’s angle in relation to the sprocket-set. Shift down to the largest sprocket and check the distance between the guide pulley and the large sprocket. If the guide pulley is rubbing on the sprocket, tighten the B-screw clockwise to increase tension and move the pulley away from the sprocket. If there is a large gap between the pulley and sprocket, loosen the B-screw until the pulley rubs the sprocket, and then tighten it until it just clears.
The H-Limit screw high gear limit stop prevents the guide pulley from shifting any further past the highest gear and into the axle. In order to adjust it properly there must be no tension on the lower inner cable. If you feel tension, loosen the cable adjuster until there is none. Now check from behind how the chain is riding on the smallest sprocket. If it looks like it wants ride off into the axle, tighten the H-screw clockwise until it lines up. If it looks like it is rubbing on the next gear, loosen the screw until the chain is nicely centered on the sprocket. Now re-adjust the cable tension until the derailleur shifts smoothly down to the next gear.
The L-Limit screw prevents the guide pulley from shifting any further past the lowest gear and into the wheel spokes. Shift down to the lowest gear, step behind the bike, and check how the chain rides on the sprocket. If it looks like it wants to ride into the spokes, tighten the L-screw clockwise until it is centered on the sprocket. If it looks like it wants to shift down, loosen the screw until it lines up. As an extra precaution you can use your thumb to gently push the derailleur body and make sure the chain will not run into the spokes, as this could obviously have a nasty effect on both you and your bike.
The cable tension adjuster defines how far up or down the derailleur moves. Step back so you can see the chain and sprocket alignment, and then through the gears in both directions, first shifting up two and down one, and then down two and up one. The chain should look centered on each sprocket. If it is rubbing on a larger gear it means there is too much tension on the cable. Loosen the tension by turning the adjuster clockwise. If it wants to jump down to a smaller gear it needs more tension. Increase the tension by turning the adjuster counter-clockwise.
You can also use sound to check the adjustment. There is always a base-level of noise that can be heard in every gear. This noise will increase in a slightly different way depending on which way the tension is out of adjustment. If there is too much tension you will hear a metallic rubbing sound, but if there is too little tension you will hear a clicking noise as the chain tries to jump to a smaller sprocket. There is usually a cable tension adjuster on your shift lever. With practice you will be able to make small cable tension adjustments while you are riding.
Now that the derailleur is adjusted, always apply a drop of lubrication to the derailleur’s many moving parts. This will help prevent wear from dirt and rust, and it will keep your gears shifting smoothly. Wipe away any excess lube and take your bike for a test ride to make sure all the gears are working smoothly.
That concludes our tutorial on rear derailleur adjustments… have fun!
Hi. I had an accident where my bike fell off to the ground. After that, the chain is rubbing the cage of the lower pulley in the rear derailleur. It's making metallic sound, as it rubs against the cage. Heare are some images for you to look. I appreciate you valueable response on how to fix this. I am using Shimano Sora. The images are taken while the bike has been mounted upside down.
... Read more >>
I bought my bike from Walmart (first mistake lol) during my first ride on the bike a bolt fell off and the line that leads to the shifter flayled from its holding. I have never dealt with this kind of problem before but being the macguever I am I attempted to fix it. I found a bolt to fit it and wrapped the line and bolted it in place. The bike functions now but won't shift gears. Occasionally while riding it, it will make a click and the pedal will fall quick making it hard to keep balance on the bike. I think I didn't wrap the wire tight enough but I need help, how do I fix this? What exactl... Read more >>
I have recently got an entry level bike and bought it without realising it had Shimano thumb shifters, i have got some Shimano STI levers and wanted to change this over. Is it possible for me to do this at home or do i need to pay out for a professional to do it? obviously I would prefer to do it myself. What are my chances?... Read more >>
So I have a trek 1000SL that I'm trying to get tuned up for ride the rockies this year. It has Sora triple shifters and everything else tiagra (9speed), and the rear derailleur won't shift up or down. When I use the shifter, it still gives and takes tension from the cable, which makes me think it must be a derailleur issue and not a shifter issue. Would getting new cables/housing fix this or do I need a new RD or a whole new gruppo?... Read more >>
Hi I was wondering if anyone could give me advice on the shifters on this Schwinn Caliente (From 1980s). I just bought it from a guy I found on craigslist, everything is in great condition and the shifters work, they're just a little tricky seeing as how this is my first road bike and I am used to the cheap mountain bikes you get from walmart. I will post the only pic I was able to get before it got dark, if you need better pictures some direction on what pictures I should get would be great. Thanks in advance!! I'm basically wondering if I should look into replacing them if there is an easier... Read more >>
Hi. New member here.
Any ideas on a brand new "hybrid" bike with 18 speed Shimano Tourney gears fitted which is occasionally throwing the chain off the smallest (high gear) rear sprocket?
The stops are adjusted correctly as far as I can see, or at least so that the chain will only just go over onto the smallest sprocket from 5th. No cable tension as such in that gear, but no slack. Stops are moving the arm. Gears generally seem to change OK. There doesn't seem to be any slackness or anything in the arm, and idlers. The arm seems straight. Front gear was on the centre chain ... Read more >>
I have a Cannondale T700 Touring bike that I bought in 1994. I upgraded the components to Shimano Ultegra 600 with STI shifters. The rear derailleur is Ultegra 7/7 with an HG 90 8 Speed Cassette (13x26). I know this from the receipt that I still have. The front is a triple chain ring, but in 1994, the STI shifters did not do 3. So we found an aft4ermarket piece that you could add at the shifter to make it work 2 rings at a time (top 2 or bottom 2) by flipping the lever which lengthened and shortened the cable. After many years, my bike fell the other day and when I tried to catch it, ... Read more >>
I have a Shimano "050" front derailleur, and every few months, the cable is breaking - always at the same location at the point where it is tied to the clamp (which is held by the bolt on the derailleur).
I am using top routing, and here are the instructions as published by Shimano:
http://techdocs.shimano.com/media/techdocs/content/cycle/SI/Tourney/FrontDriveSystem/SI_6DK0B/SI_6DK0A/SI_6DK0B_En_... Read more >>
Slowly upgrading to 11-sp over the winter. Received Front Derailleur, FD-6800 and there are unexpected parts in the box, in addition to the derailleur proper. Shimano is very slow to post tech specs and installation instructions on their site and they don't offer an e-mail querry service. All that is included in terms of documentation with the part is information on operation.
Attaching photo of derailleur with what I am guessing to be a cable installation template; the white plastic TL-FD68 placed onto the pins on the rearward face of the FD. Wonder if I have it on there correctly?<... Read more >>
I just replaced my rear derailleur with a new one of the same type (Shimano 105).
The only problem I ran into was trying to put the cable back through the barrel adjuster. The end of the cable started to fray, and I could not thread it through anymore. I trimmed a little off the cable, got it threaded, got it attached under the little clamp, and not I no longer have the big cog or the two smallest cogs when I shift.
I am very hesitant to touch the limit screws, as adjusting them without knowing what I was doing is what broke the last derailleur.
Could t... Read more >>
This afternoon I removed and cleaned my shimano 105 cassette on my road bike. When I put the cassette back together and back on the wheel, everything fit together per the documentation on the shimano web site except for the absence of one spacer that was on the instructions, but was not on my bike (the spacer to the left of the largest ring).
I put the bike on my trainer, and tried testing by hand the pedaling and gear shifting to make sure everything was working. I noticed that it would not shift into the the top ring, and it was shaking/clicking on the bottom chainring.
... Read more >>
Ive got a bike that when I try to shift to the highest gear (3) on the front Derailleur, the back Derailleur catches and ends up being pulled forward and catches completely, stopping the pedals as well.
I'm not sure how to fix this.
N... Read more >>
I'm new to this forum. I've just started working on getting an old 12 speed road bike that was given to me back into working order. I don't have much experience with bike repairs so I've been learning as I go.
The rear derailleur on this bike is an old suntour derailleur. I couldn't find any model number anywhere on it, even after spending half an hour with a rag and a can of WD40 getting all the grime off it.
I'm a bit confused by this derailleur, because unlike the shimano derailleurs on the mountain bikes that we have in our household, the uppe... Read more >>
My bike and myself are now antiques. I have a wheel (which I recently rebuilt) that has a Campy thread-on 7 speed block. It is now apparent that it is badly worn and no longer acceptable. I cannot locate a compatible replacement and I was scratching my head and thinking whether it would be any easier to find an 8 speed. I certainly no longer use the 11 tooth sprocket so I would be happy never being able to shift to it. I believe that the cog spacing on 7 and 8 are the same, so it should work.
Can anyone give me any help with this problem? Thanks.... Read more >>
I have a 6speed autobike classic. the problem is when i stop and start to pedal again the chain slips behind the gears. when I'm going downhill or fast it changes properly but otherwise won't stay on the gears what can i do to fix this? Please help enclosed is a pic... Read more >>