important: Nuts and bolts on your bike should always be tightened to the manufacturer's specifications.

How to Adjust Your Rear Derailleur

Applies to most 3-chainring derailleur systems. Adjust Front Derailleur

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!

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

Rear Derailer

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 Links

Related Tools

Categories

Discuss this topic in the Bicycle Repairs and Mechanics Forum

Hi BikeRiders Does anyone know if a 1x GRX crankset will fit on a frame with boost spacing. I’m specifically looking at the crankset for my Cinelli Hobootleg GEO frame. Note, the GEO frame is a 29+ adventure frame. It’s quite different from the other Hobootleg models. Thanks for your help....

Read more

Inner Tube Issue

Lastest post 6 days ago

In the spring I installed a new Fenix 26 x 1.90/2.125 inner tube on my year old mountain bike front wheel. It has been fine all summer until my last ride this fall. The following day after my ride both front and rear tires were flat. I thought that they might have lost air due to the cooler temperatures. But that was not the case. The tubes had failed. The tubes were inflated to the recommended 50...

Read more

Help with Hubs

Lastest post 6 days ago

Hello all! New member. Am I able to fit an 11 spd hub from a disc wheel on an 11 speed wheel that uses rim brakes. Thanks for any help!!...

Read more

Chain wear to 0.75 too fast

Lastest post 6 days ago

Hi, got a fresh new KMC chain back in August for urban commuter bike. Have lubed it twice during this time, and weekly I cover around 30 miles on the bicycle. Measured chain wear yesterday ... it's worn already until the 0,75 mark. Isn't this too early for a chain to be done??...

Read more

In modding my Jaguar, I’d like to replace the crank and forks with something improved. I have been unable to locate specifications For either that will enable me to search for compatible replacements. I’d like to go to a 3 piece crank that has more ring gear options available. Any guidance on how to identify the specs of the crank and forks are greatly appreciated!...

Read more

I just registered here to ask for help. I have this bike; https://www.bikepedia.com/QuickBike/BikeSpecs.aspx?item=91408 Which I rescued from the trash. I know how to do the basics, like changing a tube or tire, but I don't have a lot of experience replacing parts, or doing much bike maintenance in general. To be honest, I'm not a hardcore cyclist. To me, the bike is mostly just a way to get pla...

Read more

Shimano's gearbox patent

Lastest post 4 weeks ago

So I read about Shimano filing a patent for bicycle gearbox both for MTB and road bikes. What are your thoughts about it? They must be serious about it and definitely have the R&D capacity compared to the existing bicycle gearbox manufacturers. Looks like an ebike motor. I've always been (and probably will be) a derailleur boy though. https://patentimages.storage.googleapis.com/ac/c6/46/60b59...

Read more

Homemade chain oils?

Lastest post 1 month ago

Has anyone had any luck with homemade chain oil? im looking for some recipes, a lot include motor oil and mineral spirits any good?...

Read more

WD40 is not the best

Lastest post 1 month ago

There is a product used in major tool rooms I have been in as an engineer for 34 years. It is called Kroil. I think you would have to get it off the web though, but believe me it is the BEST I have seen..... Penetrating-Lubricating Oils Loosens Frozen Metal Parts! ... Nothing Works Like Kroil Kroil - An industry proven penetrating oil that has no equal. Used by 480 of the Fortune 500 companies! ...

Read more

I've read other threads and lots of info online, and I'm still stuck. My son is unable to shift the gears on his new 6-gear bike. We tried adjusting the derailer to release some tension and tinkered with adjustments here and there, and nothing seems to be working. Is there anything that we can do? I really want him to be able to shift his own gears. Going uphill today we had to stop several t...

Read more

Broken spoke - what to do?

Lastest post 2 months ago

Had an accident on the way home today. Luckily no one got hurt except for my bike. Front wheel now has one broken spoke. Can I still save it somehow? Or do I need to get a new spoke and are they sold one by one just like that? Or better to visit local bike repair?   broken-spoke.jpeg (Size: 162.16 KB / Downloads: 98) ...

Read more

Nexus hubs

Lastest post 2 months ago

Hi. I don't get why would you choose nexus hub over the classic derailleur shifters? Isn't it much pain when the hub brakes? Or am I just too used to the derailleurs and shifting .. #justasking...

Read more

Hello, bike riders! Our community member Gabriel has shared his unpleasant experience with Deore T610 brake levers: "After 2 years of very limited use ... I'm still trying to understand why is there so many holes in such a critical place" Can anyone help by explaining the reasoning for such lever design and what might be the cause of the particular break (material quality, usage, design flaw). ...

Read more

Dented top tube on a steel frame

Lastest post 2 months ago

Hello! I was forwarded here from from Reddit, where I asked around about this dent I caused. So long story short, I dropped this frame by accident on a sharp corner and it caused a smallish dent. I've been told that this is no concern on a steel frame, but I'd like to be 100% certain, if possible. Edit: added the picture...   IMG_05102019_215231_(1080_x_1080_pixel).jpg (Size: 181.86 ...

Read more

Double butted frame

Lastest post 2 months ago

Ciao. I have been looking at road bikes and most of them (unlike my Giordano) have double butted frame. Can anyone explain what are the advantages or characteristics of such bicycle frame? Like an elderly would explain it to a child ...

Read more