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
Most derailleurs have a tension adjuster, so I’m assuming yours is missing for some reason. It would be best to find a replacement that will work, maybe even on the shifter itself. If not, you’ll have to do it with the anchor bolt, which as you are noticing can be very frustrating.
Hey Alex,
I have an annoying shifting problem with gear 5 down to gear 6 and gear 6 down to gear 7. I have a shimano deore hollowtech II 33-44 on the front and 8 speed shimano tiagra 12-13-14-15-17-18-21-23 on the back. Second hand shimano aivio shifters and a shimano altus derailleur (MTB). Most parts have done about 121 miles however the shifters have done more and the derailleur has done 700.
I just cannot get these gears to work. my initial thought is my top pulley isn’t close enough to the cassette – and it’s adjusted as close as possible. As it is a mountain bike derailleur it might not be designed to be that close in 5th and 6th gear. When I manually move the pulley closer it seems to shift better. Do you think I’m in need of a road derailleur or is there a solution I have overlooked?
Thank you for your time.
Daryl
Hi Daryl,
Going by your description, I suspect that your rear derailleur hangar (where the derailleur screws into the frame) may be slightly bent. It’s a very common problem that often happens if the bike has ever fallen down on that side, but it requires an alignment tool to correct. Your local bike shop should be able to check it out for you for a small fee.
On my rear derailleur the chain sometimes comes off the lower pulley (jockey pulley?) and gets stuck between the lower pulley and derailleur cage. I only have this problem when I am using the front middle chain ring, and this never happens when I use the largest front chainring. Any suggestions?
Thanks for the awesome videos! You Rock!
Great site you have and the tutorials are very well explained.
Nice to be able to do more of this common maintenance stuff you’re self. I’ll definitely give it a shot!
When I ride my bike and coast, my chain binds up and pops, again and again until I start pedaling again.
hello,
I happened upon this web site thanks to Wikipedia. I have a new bicycle with 6 gears! The last bicycle I had was a childrens’ one with no gears! Since I don’t drive, gears are alien to me and I found one I like and I’ve stuck with it even if I have to walk the bicycle uphill!
I’ve watched your video and read some text on your web site and now I’m that bit wiser. Your web site is clear and technical but can be understood by mere novices like myself.
In future, I may experiment but in the meantime, I’ll be comfortable.
Keep up the good work!
the tango doll here in Kent in the UK
Great video… I don’t have a lot to say other than that… oh yea thanks for your help…
Hey, love your site! Total bike newb here. Recently bought a 2007 Giant OCR-1, mostly 105 components, have about 250 miles on it. Today the rear shifting wasn’t smooth (wouldn’t shift to bigger sprockets always) so I started twiddling around with the barrel adjusters that are on the cable just outside of the shift lever housing(while riding). Yeah, I should have watched this video first!
With my trial and error approach I did get it much better. Not as perfect as the initial bike setup but good. I’ll use your article to fine tune hopefully. Some questions came to mind:
If one uses these adjusters over time to take up cable stretch won’t they eventually run out of adjusting range? How can one tell this with this type of in-the-cable barrel? When cables get replaced, do the barrel adjusters usually get reset to a “neutral” position?
Happy Biking!
Tony Rozga
Fort Collins, CO
Thanks Tony,
Cables will eventually stretch past the adjustment abilities of the barrel adjuster. At that point you can either replace the inner cable or reset the barrel adjuster (turn it all the way clockwise) and then take up the slack at the cable clamp and re-adjust the derailleur.
Great video. Simplifies what on the surface (reading manuals) looked a complex process.
Ah, I understand now!!
heh. I have been riding around on a poorly adjusted derailleur for months now and it finally got to me today. I took it in to a shop and the guy didn’t even fix it. Nor did he manage to fix my brakes. So much for ’support your local LBS’.
The other LBS couldn’t even be bothered to have a look at it since it wasn’t worth his time… and my frame isn’t a Giant.
Anyhow, I have always felt deeply intimidated by derailleurs, front and back and really could not figure the back one out.
That ended today.
I sat down with this video and went over it again and again until I understood it and 20 minutes later, my shifter worked as well as it did 7 years ago when I had access to serious pro mechanics. Silent and smooth. In every gear. Not bad for a 10 year old derailleur.
FWIW, the thing that made the difference was paying close attention to the part where it says to loosen the cable tension, THEN adjust the High screw, THEN ***RE-ADJUST the cable tension***.
Those two turns of the cable adjuster made all the difference.
There’s a BIG frickin’ coffee coming your way dude!
Many thanks.
Alex or someone who knows: why is the B screw even necessary? Doesn’t the huge shiny allen key bolt hold the body in place enough?
or is the Allen key bolt supposed to be slightly loose? I’m confused.
@Paul,
The allen key bolt should be tight. The b-screw is for adjusting the top pulley’s distance from the sprockets. Check out the video at the top of this page at about 1:08 for an explanation.
Right. I assumed the allen key bolt was tight enough to keep the body from rotating but taking a closer look at the vid it looks like the body angle needs to change dynamically as the gears are shifted.
However, my derailleur is ancient, as is my bike. My B screw simply contacts the metal hook that attaches the entire assembly to the dropout. There is no little spring on the back and no “tensioning” to speak of. This is why I was confused. I think all my b screw does is prevent the derailleur body from rotating too far left.
Here’s the derailleur in case you’re interested:
http://www.disraeligears.co.uk/Site/SunTour_GT_derailleur_%283rd_style%29.html
By the way thanks for these videos I’m reading a bike repair book but a video is worth a million words.
My cable anchor bolt is not latching on with the cable. Its seems like a “spring” that the anchor bolts attaches to is missing. The anchor bolt won’t grab at all, its seems like the bolt is not the right size and just spins loosely. Plumbing tape won’t hold it. Its a dura ace rear derailleur. This is the only thing wrong with it. Am I SOL or can this be fixed?
Hi Eddie, I would take it down to your local bike shop to see if they have a replacement part.
My rear derailer is weird. I have 7 spokes but it reaches the smallest gear when you turn the handle to 6, and when you turn the handle to 1 it goes to the second largest gear, and it skips spokes in between, and it’s really frustrating, and I am not sure what the problem is.
When i did it, i didn’t really think about it and just did it and it worked.
Cheers for the Great videos. I have just replaced the cassette and rear derailleur on a 90’s Raleigh M-Trax 100 (7 speed rear) for Sram X.7 rear derailleur (9 Speed) and SRAM PG-990 cassette, with no tension on the derailleur it will still not engage the smallest cog, I have checked the adjustment screw and made sure it is not stopping it. Any ideas would be appreciated. Thanks
I wish that last part wasn’t true, I always use WD-40
hi – thanks Alex again for the info. I have some questions & Ive searched net but haven’t found answer to my problem – I was thinking can a shimano altus M310 (which shimano state as being 7-8 speed) be used on a 6 speed bike? Ive seen the tourney range (which shimano state as being 6-7 speed) but heard that tourney is nearly all plastic parts. Also is it possible to fit the rear mech without breaking the chain? e.g by undoing the two cage bolts? thanks for the help & a fitting a rear mech vid would be sooo kewl… for newbies like myself