The gears and brakes of most bikes use cables. Unfortunately, these cables stretch and wear with time, causing a reduced braking and rough bike shifting.

Shifting and braking issues are among the most frustrating problems a biker can encounter. In worse cases, they can even cause an accident or damage your bike.

Fortunately, you can fix this problem using bike barrel adjusters.

A bike barrel adjuster works by increasing and reducing cable length. Turning the barrel adjuster clockwise will reduce the tension (increase length), while turning it counterclockwise will tighten the bike cable. A barrel adjuster will help you fine-tune your brakes and shifter with proper adjustment.

How To Fine-Tune Shifting and Braking Using Bike Barrel Adjusters

Have you ever experienced shifting gears multiple times, but it does not engage? Shifting gears is relatively easy at first, but as time passes by, shifters wear down, causing the chain to not engage the next gear like how it did before.

In most cases, issues in bike shifters only require a simple cable adjustment to fix. When there is too much cable tension, it cannot move the derailleur enough when you try to shift. It also prevents the brakes from engaging no matter how much you try to squeeze the lever.

Fortunately, a simple tweak on bike barrel adjusters can fix these problems.

Adjusting Barrel Adjusters for Shifters and Brakes

The good thing about bike barrel adjusters is that they are easy to adjust if your derailleur does not have any damage. So, it is essential to inspect the derailleurs first before adjusting. If you see any damage, such as a bent part, you need to bring your bike to a local bike shop for repair.

Below is a guide to adjusting barrel adjusters:

1. Find where the barrel adjusters that you need to adjust are

When tweaking your cable tension, you first need to find its entry point on the rear derailleur. Once you see a piece that looks similar to a knob, that is the barrel adjuster, the pice you need to twist so you can tune the derailleur and brakes.

2. Time to adjust

Stand behind your bike and turn the barrel adjuster either clockwise or counterclockwise. How you turn the adjuster will depend on how loose or tensioned the cable is. If the derailleur does not shift towards the spokes (or if you need to increase the tension), turn the barrel adjuster counterclockwise. Turn the barrel clockwise if it does not shift away from the spokes.

In addition, it is ideal only to make a half turn and then try shifting multiple times to check if the cable already has enough tension. Barrel adjusters only require light turns, so do not spin the adjuster too much if you do not want to worsen your bike’s issue. Then, repeat the process until the shifter works perfectly.

3. Adjusting the barrel for brakes

The same process goes for adjusting rim and mechanical brakes. Turn the bike barrel adjusters clockwise or counterclockwise to increase or reduce the cable tension.

Adjusting the barrel will bring the brake pads closer to the braking surfaces. This way, the brakes will work fast, preventing accidents from happening.

4. If all else fails, adjust the rear barrel adjuster.

Bike Gear Adjustment with Barrel Adjuster
Bike Gear Adjustment with Barrel Adjuster

Suppose you adjusted the barrel adjuster connected to the front derailleur, but the problem persists. In that case, the next thing you need to try is to adjust the rear derailleur. The process is the same as adjusting the front derailleur. The only difference is that you need to turn the pedals by hand while adjusting the tension. (source)

Understanding Bike Cable Tension

Your drivetrain functions well with enough cable tension. When the cable tension is too much or too little, your brake pads will rub on the braking surfaces. It can also cause your bike’s derailleurs not to shift correctly.

Improper cable tension can cause minor mechanical issues, which can be annoying if they happen frequently.

Additionally, cables may stretch after years of using your bike. For this reason, you need to adjust them from time to time. This way, you can ensure that your shifters and brakes will work perfectly every time you go out on an adventure. (source)

What is a Bike Barrel Adjuster?

Bike barrel adjusters are tiny cylindrical pieces that you can find in several locations on your bike. They commonly have serrations, making them easier to hold and twist when adjusting bike tension.

Adjust Bike Brakes with Barrel Adjuster
Adjust Bike Brakes with Barrel Adjuster

This bike piece works like a bolt where the bike cable exits. They also work like bolts that adjust the cable’s length.

In addition, these bike parts are easily adjustable as they do not require any tool. You can see them by tracing where your derailleur cables go. You can find bike barrel adjusters on:

  • the shifters
  • cable stops
  • rear derailleurs
  • between cable housings
  • mechanical disc and rim brake calipers (source)

A Quick Tip When Using Barrel Adjusters

Since barrel adjusters are easy to adjust, adding too much tension to your bike cable also becomes easy. Fortunately, you can reduce the cable tension in just a few minutes.

If pedaling your bike becomes noisy after adjusting the barrel adjuster, or if the chain shifted two cogs, you only need to twist back the adjuster by a half turn. This step will reduce the cable tension, allowing your bike to make a smooth single shift and brake.

Another essential tip to remember is only to make minor adjustments on the bike barrel adjusters. Then, test if the shifter or brakes of your bike already works smoothly. If it does not, give it another half turn and test again.

While this process may be a little slower than making a complete turn, it allows you to control the amount of tension you add or reduce to the cable.

Reasons Why Your Bike Barrel Adjuster May Not Be Working

Most of the time, your shifter and brakes will be back in perfect condition after a few tweaks on the bike barrel adjusters. However, there are instances when the adjuster does not work, no matter how many times you try. But that does not mean your barrel adjuster is the problem.

If your barrel adjuster is not working, it could be that there are other issues within the different parts of your bike.

Issues with the bike chain

Your bike chain receives constant abuse as it needs to transmit pedaling power to the rear wheel continuously. Unfortunately, these chains do not last forever. After a long time of using your bike, the rollers and rivets of the chain will start to wear down, which loosens the chain and prevents it from working correctly.

This wear down can result in poor shifting to the cogs. Of course, the initial fixing you will do for this issue is to adjust the bike barrel adjusters. But if the problem is the bike chain itself, you will not be able to fine-tune the shifter and brakes when you tweak the barrel adjuster.

Instead, check if your bike chain is still within the tolerable wear limits. It is also ideal for inspecting if the chain has enough lubrication as a dry chain makes excessive noise when pedaling.

Dirty cable system

A bike cable is one of the common places where you can find shifting and braking-related issues. The derailleur will not move consistently when the shifter pulls and releases the cable if the cable has too much friction.

Dirt and gunk can enter the cable’s housing. This dirt can create friction within the system, slowing the shifting. In addition, this friction will prevent the bike barrel adjusters from fixing any cable-related bike issues.

For this reason, it is ideal to check the cable regularly to see if it needs cleaning. If you see a part of the cable, check the housing stop and find if there is a split or opening. This way, you will be able to see the underlying damage that prevents the brake and shifter from working well.

Put your bike on the lowest gear and shift the derailleur without pedaling to clean the cable. This step will slacken the cable, allowing you to remove the housing from the stops.

Now that the cable is free from the housing, you can proceed to clean the cable. You can also slide the housing back and forth to see if there is still too much friction.

In addition, you can wipe the cable with some lubricant before putting the housing back. Finally, check if you were able to fine-tune the shifting and brake. (source)

Summing Things Up

Bike barrel adjusters are a simple yet advantageous part of a bike. It allows you to adjust your bike’s cable so that the shifter and brakes will work smoothly.

Fortunately, you can install a barrel adjuster on your bike. If you plan to do so, there are many options online that you can choose from.

Do you have comments or suggestions? Feel free to drop them in the comment section below!

To sum everything up, a bike barrel adjuster is a tool that lets you tune up your bike the easiest way possible.

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David Humphries is the creator of DIY Mountain Bike. For me a relaxing day involves riding my mountain bike to decompress after a long day. When not on my bike I can be found wrenching on it or making YouTube videos at 👉 DIY Mountain Bike Read more about David HERE.


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