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Adjuster Barrel

Founder, Mr. Mamil
Adjuster Barrel on Rear Derailleur
Adjuster Barrel on Rear Derailleur

An adjuster barrel is a small device that allows you to fine-tune the tension of your bike cables. It can be found on different parts of your bike, such as the brakes, the shifters, the derailleurs, or the brake calipers.

By turning the adjuster barrel clockwise or counterclockwise, you can increase or decrease the length of the cable, which affects how your bike shifts or brakes. Adjuster barrels help make minor adjustments to your bike’s performance, especially when the cables stretch or wear over time.

However, they are not a substitute for properly repairing your bike components. You should always check your cables and housings for dirt, damage, or corrosion and replace them if necessary.

Origin and synonyms

The term adjuster barrel comes from the shape and function of the device, which resembles a small barrel that can be rotated to adjust the cable tension. Some synonyms or related terms are cable adjuster, barrel adjuster, or inline adjuster.

Examples of Adjuster Barrels

Some examples of adjuster barrels for cycling are:

  • Shimano SM-CB90 Inline Brake Cable Adjuster. This inline adjuster barrel can be installed on the brake cable housing near the brake lever. It allows you to adjust the brake cable tension without using tools, and it has a quick-release function that lets you loosen the cable for easy wheel removal or installation.
  • Jagwire Pro Indexed Inline Cable Tension Adjusters. These inline adjuster barrels can be installed on the shifter cable housing near the shifters. They allow you to adjust the shifter cable tension with a simple twist and have index marks showing the adjustment amount. They are compatible with Shimano and SRAM shifters.
  • Park Tool BT-2 Cable Stretcher. This tool can pull and hold the cable tight while adjusting the adjuster barrel. Its built-in thumb lock secures the cable, and a one-hand operation frees the other hand for turning the adjuster barrel. It can be used for both brake and shifter cables.
Alex Lee at Mr.Mamil

Alex Lee is the founder and editor-at-large of Mr. Mamil. Coming from a professional engineering background, he breaks down technical cycling nuances into an easy-to-understand and digestible format here.

He has been riding road bikes actively for the past 12 years and started racing competitively in the senior category during the summer recently.