How To Adjust Your Rear Derailleur
Applies to most 3-chainring derailleur systems. Adjust your Front Derailer
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DownloadAdjusting 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!
Required Tools
You’ll need a rag, a phillips screwdriver, a 5mm allen wrench, and a light lubricant like Triflow or Phil Wood Tenacious oil.
Rear Derailleur Components
Loading ...How They Work
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.
Limit Screws
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.
B-Tension Adjustment
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.
High Gear Limit Stop
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.
Low Gear Limit Stop
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.
Cable Adjustment
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.
Lubrication
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!
Related Tutorials
This video is also available on DVD Volume 1
Hi Alex,
I’m a newbie to all this bicycling thing, I started to ride MTB about 2 Months ago and I just got me a new Cube LTD Race last Thursday. As soon as I got it I tried in the mountain, it was sweet but there was some problem changing gears. I’m a DIY guy, so I wanted to fix it myself. I researched the web a lot and found your website. I must say I find it extremely cool that you do this videos and share your knowledge.
As for my bike, well I think I made a frustrating huge mess instead of fixing the problem. I have never been good with mechanics. I’ll have to take the bike to the shop tomorrow.
Anyhow, just wanted to drop a line in here.
Keep the good work!
Very helpful and impressive video! Thank you for this information.
Despite my embarrassment, I’d like to mention for any other diy bike repair novices trying this adjustment that the hex wrench should be used to loosen the rear derailleur’s inner wire pinch or anchor bolt. Don’t make my same mistake and try to adjust the rear derailleur by reducing tension on the wire only with the adjusting barrel. Also, be careful when pulling on the inner wire once you have your limits set and are re-tensioning again or you may fray the wire badly, as I did (requiring a whole new cable).
I’ve been trying to fix this issue for three weeks… You’ve already helped me SO MUCH with all of your videos – I hope this is a simple question.
My bike, recently, has begun throwing the chain when coasting. It gets so much slack on the top! It looks to me as if my “upper guide pulley” is too far from the sprokects, so I hoped loosening the b-screw could help. But…I don’t have a b-screw! I looked for ages. I’m guessing the bike is at least 15 years old.
Could it be my chain is too long, and if so do you have any idea why this problem wasn’t showing up before?
Carl, it sounds like your freewheel is sticking. You can get them flushed out if your local shop has the tools, otherwise you’ll have to replace it. I’d take it down there and see what they recommend.
Alright, first off your tutorials are amazing and have helped me out tremendously!!! I have worked on my bike and fixed and tuned it from learning off of your videos.
Second I have a small problem with my rear dérailleur. I cant get it to shift into the larger gears. I can shift into them, but there is an incredible amount of force required to do so. My cable will actually creek because it is being pulled so tight. My dérailleur is a Shimano Deore with Deore rapid fire shifters.
Thanks for your help,
John Martin
Sounds like some of your components might be dry. I would try lubing the cable housings and also all of the pivots on both your shifters and derailleur with some light oil (like Tri-Flow). If it’s still the same your cables may be corroded and need replacing.
I just got some finish line wet lubricant, would that work? or would you suggest going out and getting some Tri Flow?
The finish line wet lube is too thick for cables and pivots. I’d definitely recommend the Tri-Flow.
I teach a bike course at the University and have found that if I refer to the tension adjustment as a device that lengthens or shortens the housing thus having the opposite effect on the cable, much nodding of heads follows.
Cheers
Hey just want to let you know that the tri flow worked wonders on my shifter cable. The cable housing in the back had a lot of grit in it and it cleared it up very nicely. Thanks for the help!
John Martin
Alex, let me say thanks first of all for this web site. I just found it and love it! I just replaced my rims and tires on my GT (I installed HyperLite’s) but noticed that when in the highest gear, the chain kept jumping around from the smallest to the 2nd smallest sprocket. Now that I have viewed this video several times, I will try making these adjustments.
Also, had no clue not to use WD-40!
Thanks again!
Rueben
The rear derailleur on my bike is playing up. With the 6th gear selected it goes all the way to the 7th and with 1st selected it stays on the 2nd unless I change the front derailleur to 1 and then the rear one goes to 1 automatically. Do you think it has to do with the High/Low gear limit screws? What should I do?
No, it wouldn’t be your limit screws. They stop your chain from falling off your largest/smallest sprockets. It sounds like you cable tension needs adjusting (3:00 in the above video).
Alex just wanted to give you a response on the comment you had for me up above. You were absolutely right. I’m now rolling along just fine on a brand new freewheel!
You rock.
Alex ..
I have loosened the cable tension all the way .. it’s still not going up the 1st gear :-s Do I need to loosen some of the wire out and then play with the screw?
Alex ..
I think I’ve messed it all up now… I got the cable out and have tightened it… any idea if you get the cable out how much tension should there b to put it back together? What about the tension adjustment screw… where should it be when you put the cable back? I will start again on this a bit later… you are right… it is a bit of a frustrating challenge.
The cable tension adjustment is explained in the above video at about 3:00.
I have always eventually managed to get the derailleur adjusted properly. Your tutorial, order of operation, made the job a lot easier. ThanX Question: I had to turn the chain clearance screw all the way in. Is this more likely due to wear on the end of screw or loosing spring tention?
You’re probably right about it being the spring tension, depending on how old the bike is.
ehlo.
Great site, good tutorials, thanx a lot man! I was in deep shock when I heard about wd40. Thanx.
pete
I wouldn’t have had a hope of figuring this derailler malarky out were it not for your site, thanks a million man .
Hi Alex,
Excellent site and videos – thank you. Any thoughts on replacing a rear derailleur? I’d like to carry out a minor upgrade (Acera to Deore) and I’m wondering if there are any pitfalls (e.g. special tools required) that I should be aware of. I’m assuming that the box will contain some sort of fitting instructions…
Status of this Request
Hi Alex,
Your videos are so useful! I have a question though, as this is a bit confusing… I just got a new bike, and when I peddle backwards, the chain ‘falls’ onto the higher gears. What do I need to adjust to sort this out?
Thanks in advance,
Lawrence
Lawrence, as long as your gears are shifting well when you pedal forwards I wouldn’t worry about it. Multi-geared bikes are not meant to be pedaled backwards so there’s often some noise/jumping when you do.
Alex,
Love the videos, I replaced my rear cassette with your help. The guy I bought a bike off had a road cassette and I put a MTB one on.
Now the problem, I can’t get the derailer to shift to the lowset two gears, it just gets stuck. And in the the 3rd you can hear and feel a clicking like it wants to shift.
The highest 4-5 gears seems fine. Is this because the derailer was set up for the road cassette?
And what adjustments do I need to make for the derailer to get the chain on the lowest gears?
Thanks,
Aaron
It sounds like your rear derailleur’s ‘L’ (low-limit) screw is too tight. Watch the video above at about 2:25 for tips on how to adjust it.
Aaron – It sounds like you currently have an eight speed cluster – is it replacing an eight-speed? Is it from the same manufacturer? If any of these have changed then the sprocket pitch is likely to be slightly different and the shift mechanism may work over a small range of gears but not the entire set. See the table in this link:
http://www.ctc.org.uk/desktopdefault.aspx?tabid=3946
Assuming that’s OK, and adjusting the L screw doesn’t fix it, the next thing that strikes me is that the largest sprockets (lowest gears) in an MTB set are likely to be much larger than in a road set. If this is the case you will first have to adjust the B screw (see Alex’s tutorial, Step 4 @ 1:20) so that the derailleur guide pulley has enough clearance, otherwise it’ll never make the jump.
Secondly, check the cable tension. See step 5 in the tutorial – ideally you want the minimum necessary tension when the mechanism is on the highest (i.e. smallest) sprocket (assuming also that you have a ‘top normal’ derailleur – where the mechanism is spring-loaded to pull the chain down to the smallest sprocket).
(Note to Alex: Alex – forgive me if I appear to have gone from complete novice to (self-appointed) expert in a couple of weeks. I have, since my post on Sep. 10th, successfully fitted a new derailleur, and it was a great fun, if a little frustrating at times (I think they call it a steep learning curve…). I couldn’t have done it (and wouldn’t have attempted it) without your tutorials.)
thanks, it helped me a lot adjusting my bike derailers.
What do you do when your pedals pop forward really fast without moving the tire whenever you put much pressure on them?
Sounds like a your chain is slipping on your rear sprockets. The most common cause of this is a worn chain. If it is worn, often you’ll have to replace the rear sprockets along with the chain, as they’ll wear together. Your local bike shop should have a chain wear indicator and will check it for free.
Hello Alex,
I personally like the chain to derail as 2nd being 1st and if you hold the shifter above 1st its the actual 1st, is this bad?
Hi Taylor,
I don’t quite understand your question…
When it says your in first, on the shifter, its adjusted as is its in second.
You’ll have to undo the cable tension, and then tighten it when your shifter says it is in the highest gear (probably 7 or 8), with your chain on the smallest sprocket (highest gear). Then you may need to work through the gears as explained in the video until the adjustment is right throughout all your gears.
Alex,
I found my rear derailer’s H and L screws very easily, nicely marked and all. The only other screws I can find are obviously holding together the separate parts of my derailer. Do some bikes not have b-screws or is it just me???
Yes, sadly some economy rear derailleurs are missing the ‘B’ screw. They don’t leave much option but to replace the derailleur if you have to make that adjustment.
Nice videos. I just bought a Salsa La Raza with Shimano 105 and your site has been a great help for getting me started. I heard that WD-40 is a good water displacer after you wash your bike to prevent rust but you should lube the chain nonetheless. Would you recommend taking this step, is it simply unnecessary or perhaps harmful?
All you really need to do is lube the chain, the chain oil itself will act as a water displacer!
Alex
As a mechanical engineer I am embarrassed to confess I had absolutely no knowledge of how to do this. All I do know is that I have been doing the wrong thing for a long time….
Your tutorials are simply brilliant and you should be very proud that you are helping lots of people around the world.
Thanks
Jimmy
Australia
Alex
Simple, clear and brief: just one day of viewing your tutorials has given me skills lesser authors have been confusing me about for years.
Thanks a million buddy!
Jon (UK)
Thanks for the exceptionally clear video.
I’m very embarassed to say that I have used WD40 on my bike. Now I wonder if there’s a way to remove any residual so I can apply the correct lubricant.
Thanks,
Mark
Mark, I wouldn’t worry about the residuals, so long as you apply oil from now on it should be fine
Hi Alex,
The chain on my rear derailleur shifts to a gear higher than that shown in the shifter, i.e if the shifter is turned to 4 the chain shifts to gear 5, or, if the shifter is turned to 3 the chain shifts to gear 4. The chain does not shift to gear 1, it slips off to gear 2. Any advice, and thanks in advance.
Hi Alex, thank you SO MUCH for your site. I can only read so much Sheldon before I need to see an example!
I recently tore apart my bike and swapped out some components to make it into more of a commuter. I just installed a SRAM x7 rear derailleur on a surly cross check. Everything seems alright except it rattles and vibrates a lot.
My B-tension adjustment is loosened all the way and there’s still a pretty sizable gap, around 7 or 8mm in the smallest ring and more when in the largest. I’m probably just being paranoid as this is the first time i’ve done this, but is there any reason it would do that? I may have sized my chain incorrectly (new sram 9 speed chain with masterlink, I added the two links plus the master link, not two links including it). Could the gap be explained by the 1:1 actuation ratio?
Hopefully this may help someone in the future (and me now!
@Arvind: It sounds like your cable tension needs adjusting. Check the video up top at about 3:00 for tips on how to set it up.
@Chris: Try setting up your chain length with two links including the masterlink… it sounds like it might be a bit long.
This is Raleigh Ron, still checkin out you vid’s. Lookin good, man. I post them on the Schwinn forums everytime somebody needs help. Keep them comin, I plan on listing your web address on my site again soon, Thanks..
My entire drivetrain, derailer included, is completely gunked up to the point where it jams and doesn’t shift well at all. The gunk is thick, like clay. And it’s quite deep in between the parts. Is there an environmentally-friendly bath, wash, or solution that I can use to clean all this down to the metal. Is there also a particular technique to use?
Sounds like you need a drivetrain bath. I’m planning to do a video on this too. Basically you’ll need to take off your crankset, chain, cassette/freewheel and both derailleurs. Then soak them in some environmentally friendly solvent like Ecotech for 20 minutes. Then use a brush to clean out the gunk and rinse with water before air-drying. If you have a compressed air unit it works wonders for blasting out any remaining water and solvent. Then re-install and lubricate!
What is your advice if my derailleur doesn’t have a tension adjuster? I have been turning the anchor bolt clockwise in order to create a little ‘belly’ of slack in the cable while I do my screw adjustments, but so far my derailleur is not seeming to respond accurately to my adjustments.