How To Adjust Your Rear Derailleur
Applies to most 3-chainring derailleur systems. Adjust your Front Derailer
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!
You mention not to use WD40. I have heard that advice before and it was suggested to me to use GT85 instead, what is your take on that?
WD40 is a solvent, good for stripping rust and un-sticking seized parts. It is not a lubricant and should never be used on your drivetrain, cables, bearings, etc… I only mention it because it is a common misconception. In my years as a mechanic I saw many damaged bicycles because people thought it was good to use WD40 on their chain - or even worse - in their bearings.
I don’t know GT85, as I’ve never used spray lube before. It doesn’t look like something I’d use. Regular bicycle chain oil always works the best. Triflow or 3in1 works well for cable housings and pivots, and obviously a good waterproof grease for bearings.
More about the harmful effects of WD40 here:
http://bicycletutor.com/no-wd40-bike-chain/
Very well done and helpful, Alex. Thanks for your efforts and looking forward to more lessons.
Great job with the video. I’ve been a dedicated cyclist for over a decade, so I appreciate it when a “brother” shares his passion for our wonderful sport. Keep’m coming!!
Thanks for all your comments and support. I learned a lot making this video (particularly, that making videos isn’t easy), and I’m really excited to record the next one!
Yeah! I just “stumbled” here, and I was hoping that with only two videos it wasn’t an old-dead site… luckily, I see that it’s young and active!
Keep up the good work, see you around!
Alex,
Just found your site through bike forum. I hope you can keep these up, they are proving most informative. Well done.
Just arrived here via Stumble. I will be subscribing to the feed as I need all the help I can get when it comes to fixing my bike.
Great video. Thanks !!!!!
Fantastic video! I was actually doing some research on the front derailleur when I stumbled across your site. Maybe we will see a video on the front derailleur soon! Brilliant job as it makes life so much easier for a novice like me.
http://bicycletutor.com/adjust-front-derailer/
NIIICCCEE!
You say not to use WD40 on my bike. I use TONNES of the stuff. Maybe thats why all of the gears click…
Hi great job on the videos. Unfortunately your advice has come a little late and I used WD40 on the chain and sprockets about 2 days ago to clean them. I did use chain oil afterwards but should I do something else to remove the WD40 first ????
Hi Eddie,
No you don’t need anything to clean the WD-40, as it already acts as a cleaner. You can go ahead and lube the chain, it will be fine.
ALex,
A comment from Downunder (Australia). Well done. The first problem I was researching was on how to adjust my derailleur and presto - your site answered ALL my questions. I was determined to make up a similar site myself when I learned enough but you have done that.
A link to your site was found at a Sheldon Brown’s site (bike junky) (http://sheldonbrown.com/derailleur-adjustment.html) and was useful but yours takes the cake.
Steve
Thanks for the fine and informative video tutorials Alex. As an avid cyclist but not a mechanic these videos have proven quite helpful.
Keep up the outstanding work and assistance to all of us!
Great site. I found it through Gerry Lauzon’s How to Fix Bikes site, with his link to your WD-40 video. The only use I’ve found for WD-40 on my bike was in removing the fixed cup from the bottom bracket, at which time I sprayed repeatedly inside and outside the cup between turns on the fixed-cup removal tool (Sheldon Brown’s home-made version.) I don’t think I would have gotten it off, otherwise.
I’ve now linked to you from my site and written a post about it.
Alex,
Very useful site already recomended to my tri club team mates.
Just one comment on rear mech adjustment. You mention the allen key in your intro but not during the adjustment process. It would help to tell folks how to use it to adjust the cable tension in the case where the cable adjuster runs out of travel or the case where you are replacing the cable or reinstalling the mech.
Graham.
Graham, thanks for the feedback. I’ve added setting up shift cables to my list of future tutorials.
Did this one too (as well as the front). Thanks again for the help! Keep then coming!
Man now I don’t have to pay someone else to do the work I can and I can spend my money on gear. this a great site that will help and encourage all cyclist. GREAT job, some videos on safety would be good too, maybe on how to merge & avoid traffic. This is where people get in trouble. Cheers mate for a great site. Godspeed, and peace.
I can’t even describe how happy I am I just stumbled across your website. I’ve been trying to find a clear, easily understandable tutorial on how to do derailleur adjustments for ages. Thanks to you I no longer need to fork over money every other week to have my bike adjusted into tip top shape. Thanks a million and happy riding!!!
I found that my chain tension is too low. When I stop peddling quickly, the slack in the chain can drop the top length of chain down and it catches under a piece of the frame. Can the tension be increased on the derailleur?
Hi Ron, no you can’t make up the tension at the derailleur. It sounds like your chain may be too long? If that’s the case, check out this tutorial.
Alex-
Excellent job on both front and back derailleur adjustments, I was becoming quite weary of driving 30+ miles one way to my mechanic, and your videos have saved me bunches. I’ve invested in a repair stand since your videos have put the pieces of the puzzles together. I spend more time riding instead of money. Thanks !
I’m an on-again off-again cyclist, and have the problem of constantly needing to re-figure-out-the-hard-way how to fix my bike. This, predictably, puts me more off the bike than on. With your site, I can now look forward to fixing things quickly and getting back on the road.
Thanks for explaining the key issues in clear language and for providing just enough detail for reference. If your goal is to keep more people happy and on their bikes more of the time, then you are succeeding, my friend!
Thanks - the rear derailleur adjustment video was superb!
Thanks for providing these videos, especially this one!
Setting the bike gears has always appeared a mysterious art to me!!
Sites like this represent the best of what the internet can offer - sharing knowledge and experience, making life easier for everyone.
Thanks again.
You forgot to mention what the barrel adjuster does.
It’s explained around 3min into the video and in the text under ‘Cable Adjustment’.
Very informative. I have learned so much more from you videos. I’ve even invested in a tool set because of you.
Keep it up, knowledge is power.
Wow. This is exactly what I needed. I need to re-pack my hubs and don’t have time to go to the local bike co-op. The list of tools is really helpful as I’m also trying to build up the things I need to fix my bike myself. Thanks!
What do you do if the B screw is all the way clockwise but the derailer is still rubbing against the chain?
Jose, I would try flipping the screw around, so the head sits against your frame. This gives it some more reach. If not, you may need a derailleur with a longer cage.
G’day. Recently had a bike that started a high pitch, intermittent, squeak while pedaling. Lubricating all of the rear derailer parts with oil did not fix the problem, except maybe in the short term. Very frustrating. Turned out that the pulleys, on the rear derailer needed grease. Getting the pulley seals off proved to be a bit of a chore, however, once cleaned and greased, the squeak problem went away. Perhaps, a rear derailer part 2, ‘pulley clean and care’ video may be in the future. Thanks Alex!
Status of this Request
Thanks Dennis, I’ve added your request to the list!
I have a bike that I bought used. I had to replace all the cables as well as the chain on the bike. Now I have the problem you described where the top sprocket is making contact with the pulley. I cannot find the B screw adjustment. It is a Shimano SIS. Can you tell me how to make the adjustment?
Hi Cat,
The B-screw is tucked in behind the derailleur, near where the derailleur screws into the frame. It pushes against the frame to make the adjustment. Check the derailleur image above where it is marked. Let me know if you still have trouble finding it!
Thanks for all of your great videos! This is helping me save some money by doing things myself.
I do have a quick question though. I am looking to get a newer higher speed cassette, going from a six to 7 8 or 9. Will my derailleur still work? How could I tell, or will I find out when installed?
Thank again!
Thanks David… unfortunately your 6-speed derailleur won’t work with a 7,8 or 9 speed cassette. However, a 7-speed derailleur will work with 8-speed and vice-versa, and a 9-speed cassette requires a 9-speed derailleur. Hope that helps!
I finally found the cause of my problem and I wanted to share it in case someone else ever encounters the same situation. On the rear wheel the pulley kept hitting the largest gear. The bracket that holds the two pulleys in place is made up of two halves. The inner half was upside down. Once I flipped it everything worked fine.
Thanks for the great tutorial, easy to follow, and maybe I can now get my MTB to stop skipping gears!
Very helpful thank you.
Many thanks for a great video.
Alex —
I took my rear derailer apart and cleaned it, pieced it back together, but now I have a major problem… first of all, I have a miniature piece that looks like a tiny metal barrel that measures just about an inch in length and half of that in width. My back gears are not shifting at all. Also, when I spin my crank backwards the rear derailer doesn’t let the pulleys move, it just drags the whole derailer along the chain. I’ll post pictures tomorrow. What do you suggest?
Hi Ryan, it sounds like that piece of metal could be one of your pulley bushings… which might be why the pulleys don’t spin. Be sure to send those pictures!
Huge Help! Thanks!
I am a professional photographer, and I have to let you know that it is hard to see the gears and derailleur in the video. They are too dark, probably because the background is too bright.
If you were planning to do a re-shoot some time, shine a light right on the gears and derailleur.
Thanks Varden,
Yeah, the lighting was bad. That was the first time I used a camcorder and I had poor lighting. Now I have several more lamps but I really can’t wait to get a bigger space with proper lights… then I’ll be re-producing videos like crazy!
I had my bike taken to the shop. A second piece I mysteriously found was a pully bushing, however I still dont know what the other piece was. Couldn’t find it online. It is shaped like a small metal hollow cylinder just an inch long and half as wide.
You´re the man, Alex!
Thanks to your coherent videos, i managed to change a spoke on my back wheel and set up a new chain, even though i never did one of those things before.
Compliments