How To Install And Adjust A Derailleur: Easy Tips (Updated In 2021)

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BY Jim Felt
Updated on 03/27/2021

Have you ever wondered how to assemble a road bike derailleur? Which component you should install first should be next to match the best, are some notes that you need to know. Here we introduce to you how to install and adjust a derailleur.

Aside from the perfect transition, one of the best things about the derailleur is that it is straightforward to adjust, accessible to anyone’s ability. You can adapt yourself to a perfect front and rear derailleur with the following tutorial.

How To Install A Rear Derailleur

How To Install A Rear Derailleur

How To Install A Rear Derailleur

The rear derailleur is responsible for shifting the chain up and down the rear tire’s gears. When a rear-wheel derailment fails, switching to and staying on a particular gear becomes difficult, if not impossible. As the derailleur can no longer be adjusted, so your cycling does not work properly, it’s time to replace it with a new one.

Move the rear derailleur to the smallest serrated and leave it in this position throughout the process. Unleash the chain off the bike with the chain break tool or quick-release link, depending on your chain use.

Loosen the shift cable link derailleur’s mounting bolt located on the rear derailleur with a hexagon wrench and remove the rear derailleur’s cable by cable cutters. Note to measure cable housing first.

Loosen the rear derailleur mounting bolt and remove the derailleur from the bike frame. Sometimes, you need to loose cable pinch bolt. Note to fully tighten the mounting bolt.

Install the new derailleur in the same position as the old derailleur and tighten the derailleur’s mounting bolt to the appropriate torque, based on the derailleur’s specifications.

Pull the rear derailleur shift cable firmly, place it under the shift cable link bolt and tighten the bolt. Replace the string, making sure it is routed correctly.

Adjust the new derailleur by appropriately positioning the body screw (low adjustment screw). Then set the low and high limit screws, and set the shift cable tension so that the rear derailleur glides slightly through the rear gears.

These steps are very essential for bike mechanics. A few things that should be noted are the following terms: turn clockwise, cable flattens, pedal forward, fully tighten, and more.

You can check out this video to see how to install a rear derailleur:

Watch video: How to Adjust a Rear Derailleur – Limit Screws & Indexing

How To Install Front Derailleur

How To Install Front Derailleur

How To Install Front Derailleur

Before doing the Shimano front derailleur installation, you should use a little grease to waterproof the mounting bolt. Then use the tools to tighten the bolt to fix it but not too tight so that you can still move it by hand.

First, to start the front derailleur installation, move it into place if the chain is in the big ring. We can do this using the transducer or pressing the function button on the trim variable.

If you are using the clip head, attach the glue to the inside of the clip, then attach it to the seat tube with a 4mm Allen buckle. Install the derailleur on the mount to 5-7Nm. If you are using a braze-on attachment, then all you need to do is attach the derailment.

Next, make sure the derailleur is properly positioned. Line the top of the smallest sprocket with the grooves on the inside of the diverter and align the front chain with the grooves at the diverter’s front and rear. If you made it right, there is a 1-2mm gap between the top of the gear on the chain and the bottom edge of the outside of the derailleur cage.

You also need to use a small protruding wedge between the slot and the front forehead unit to keep it secure on some frames.

You can check out this video to see how to change your front derailleurs:

Watch video: How to Change Your Front Derailleur - Replacing Your Bike's Front Mech

How To Adjust Your Rear Derailleur

How To Adjust Rear Derailleur

How To Adjust Rear Derailleur

The rear derailleur adjustment is an essential skill that will help you master and control your road bike with ease. By following these steps, you can tailor your conversion with confidence and save time and money. And of course, you can also do them at home with simplicity.

There are three screws to adjust on the rear derailleurs: 2 sets of chain limit screws (symbol H and L) and one screw to adjust the tension of the rear derailleurs. Each derailleur has different positions for the screws but is still very recognizable. Before starting the rear derailleur adjustment, you should loosen the 2 H-L limit screws. In contrast, the derailleur tensioner does not need to be relieved.

Step 1: Setup

You should check that the entire rear derailleur cover is in the correct position; there is no kink around the handlebar. Then check that the derailleur is in the right place. The rear derailleur usually has a fixed tab to prevent rotation. Still, due to its exposed position, it is prone to crashes. If possible, you should install protection to be sure.

Move the smallest disc to the front derailleur and the rear derailleur to the largest. Turn the adjusting crew clockwise to release cable tension.

Step 2: Adjust the high limit

Adjusting a rear derailleur

Adjusting a rear derailleur

Adjust the height limit screw at screw H (High) point. Use a screwdriver and turn the screw to move the head forward and in and out. Its position can be on the top of the derailleur or the rickshaw just below the smallest disc. Use a screwdriver to screw back to tighten the limit screw.

To learn more about this how to adjust high limit screw, please watch this review video:

Watch video: How To Adjust High Limit Screw, Shimano XT Plus

Step 3: Adjust the cable

Remove the cable anchors with the Allen key (this is the key about 5 in size on the Shimano metal wire). Pull the cable with your fingers and unfasten it. Now for the adjustment only, you need to determine the chain’s accuracy when observing the chain and gears’ movement.

At this stage, the chain will not fit the gears correctly as they move up and down the wheels by turning the screw clockwise so that tension can be increased for the change cable and rotating the crankshafts shifting between gears.

You should start to adjust the chain and gear to ensure smooth cycling. Adjust the cable tension so that when you shift, the chain moves between the gears smoothly. At first, you may find the operation a bit difficult, but you will get used to it with a lot.

Next, you use the barrel adjuster (barrel adjuster clockwise for barrel adjustment) to align the smallest sprocket after putting the chain on the half of the wheel to fix it.

Step 4: Adjust the low limit

Adjust the low limit

Adjust the low limit

To proceed with the low limit adjustment, you first shift the chain to the largest gear. Turn the low limit crew L (Low) to align the topper tire with the gear vertically. To ensure the derailleur doesn’t slide between spokes, you change the shift line between the two smallest gears.

To learn more about this how to adjust low limit screw, please watch this review video:

Watch video: How To Adjust low Limit Screw, rear Derailleur

Step 5: Adjust the tension

After adjusting L-H limit crews, you need to change the cable tension. To check, you put up the kickstand and move to the bike’s right side. Your right-hand grabs the handlebars while tilting the bike while shifting gears, while the left hand holding the disc thigh rotates evenly.

If the chain does not move smoothly or does not jump, shifting the gear lever feels heavy, which means that the shift line’s cable tension decreases. Conversely, if the chain does not flinch from time to time, or if it does, then raise the cable tension to prevent the cable slack.

Usually, this adjustment is only necessary if you have changed to a cassette with larger gears (e.g., swapping 25t cassette for a 27t cassette). While the chain is still in the largest gear, adjust the screw clockwise so that the amplifier comes close upper jockey wheel to the cassette without touching or turning on the line spins.

Screws to adjust cable tension are usually located in the rear derailleurs. This screw is designed so that each turn is one-fourth of a turn and does not swing around.

To learn more about this how to adjust rear derailleur cable tension, please watch this review video:

Watch video: How to Adjust Rear Derailleur Cable Tension

Step 6: Check

Shift the gear shift to check if the chain is up and down the sprocket smoothly and without any sway.

Note: These modifications assume the steering is not damaged. If, after following these steps, your gear still has problems, it could be caused by any factor that breaks down on a daily basis. Some of the more notable issues include: a left-hand hanger, a worn cassette or a worn chain, having a good look at your road bike.

To learn more about this how to adjust a new rear derailleur, please watch this review video:

Watch video: How to Adjust a Rear Derailleur – Limit Screws & Indexing

How To Adjust Front Derailleur

How To Adjust Front Derailleur

How To Adjust Front Derailleur

First of all, check if the entire derailleur is in the correct position if there is no kink around the handlebar. Then check that the derailleur is in the right place.

Usually, the new derailleur has a setting to adjust, and you need to correct it and then fix it, but it can be lost after a while. You move the derailleur to the largest disc and check if the gears match the stamp’s image. Otherwise, you need to adjust it to fit and align.

Then we need to see if the lever is in place. The excellent position is that when you try to pull the gear lever outwards, it will be about 3mm from the largest disc gear. If not, you need to raise the derailleur (by removing the screw that fixes the derailleur position on the axle) and adjusting the distance to the required length.

There are two main limit screws on the disc transfer part to prevent the chain from falling out of the disc with symbols L and H. The low limit screw has the symbol L (Low) used to adjust the shift line limit at the smallest disc. The screw has the symbol H (High) to change the shift line limit on the largest disc. Before proceeding, you need to loosen these two limit screws.

Step 1: Set up

First, loosen the derailleur by rotating the thread holder. Turn it completely off, then release it completely. Loosen the screw to attach the derailleur to the bicycle frame, and then slide the derailleur over the seat tube.

To determine if a position is correct, do the following. First, we temporarily fix the derailleur by adding a half. Then, loosen the Low and High limit screws completely (for running as you like). Hand-held pull to reach all the way, the height of the derailleur that is 1-2mm higher than the disc is the standard.

If the height is correct, rotate the pivot slightly so that the derailleur is parallel to the chain. Note that while tightening the fixing screw to the bicycle frame, this angle can turn, so pay attention to adjust it so that it is correct.

Next, completely loosen the handlebar’s handle by turning the screw on the end of the string to let it fully fit in (pulling off the shift cable’s end cap). We fix the cable by hand, stretching the thread and hexagonally tighten the screw holding the thread. Then test the cable a little bit by screwing the cable head on the handlebar as above.

Step 2: Adjust the low limit screw L

Adjust the low limit screw L

Adjust the low limit screw L

First, you need to shift to the largest chain. Then shift down on the smallest plate. When tightening low limit screw L, you will see the front derailleur moving into the chain.

Adjust the limit screw L so that the front derailleur’s surface is as close to the chain as possible. The surface clearance to the chain is 1 mm or less. When this screw is loosened or tightened, the lever will move outwards or inwards.

Step 3: Adjust the limit screw H

Shift to move to the smallest disc. Then shift to the largest disk. Tighten high limit screw H; you will also see the derailleur’s frame moving close to the chain.

Adjust the screw H so that the front derailleur’s surface is close to the chain, the space of the frame surface with the chain is 1mm or less. Return the chain to the rear disc in the mid-range (number 4 if the 7 or 8-speed disc, number 5 if the 9-speed disc). Then check that the front derailleur is working correctly.

Step 4: Check

Check The Chain

Check The Chain

Shift to move the disc up and down to check if the chain is touched or the chain falls out. If when switching between discs, there is a feeling of frowning, the feeling does not go all the way. You need to adjust the derailleur’s tension by increasing it like increasing the brake line. The pre-adjuster screw (barrel adjuster – barrel adjuster clockwise) is usually located on the right handlebar on the handlebars.

A barrel adjuster is important to installation and adjustment. Not that you use a barrel adjuster with a clockwise.

Finally, make sure the derailleur hanger is in good shape for hanging.

To learn more about this how to adjust a front derailleur, please watch this review video:

Watch video: How to Adjust a Front Derailleur


Hopefully, with the above-detailed instructions, you can completely assemble and adjust your road bike derailleur. Suppose you are not confident in your capabilities. In that case, I hope my sharing above will help you get the best possible installation instruction and adjustment advice. I hope you will have an enjoyable rear derailleur adjustment experience.


How long should I spend to successfully install a front derailleur?

Assembling a front derailleur on a road bike requires a lot of work, from shifting adjustment to aligning the derailleur’s position to the wheel. Therefore, successfully install a front derailleur can cost you at least 1 hour if you are a beginner.

How much does installing a rear derailleur cost?

Currently, a Shimano new rear derailleur costs around $ 30 on Amazon. If you can install a derailleur at home, you can save $ 20 on a derailleur installation service and about $ 15 on a rear derailleur adjustment.

Should I adjust the rear derailleur at home or at a shop?

Adjusting a derailleur at home can be pretty confused and complicated if you don’t have a detailed guide. There are many people, after trying to change them, end up in the local bike shop. Therefore, if you are unfamiliar with adjusting a rear derailleur or have not found yourself a practical guide, you should look to the nearest bike store. It can cost you about $ 15 for this adjustment service.

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