Shortening Shimano brake hose

Have you ever noticed that the hose on your hydraulic disc brake is a bit too long? Not only does it look untidy, but it also poses a risk of getting caught or damaged. In today’s guide, I’ll walk you through the process of shortening Shimano brake hose.

Why and When to Shorten a Disc Brake Hose on a Bicycle

Shortening a disc brake hose on a bicycle becomes necessary for several reasons, primarily related to functionality, aesthetics, and safety. Understanding why and when to perform this task can help maintain the optimal performance of your bike’s braking system and ensure a comfortable riding experience.

Adjustment to Bike Fit

One common reason for shortening a disc brake hose is to accommodate changes in bike fit. Riders may adjust their handlebar height or position, necessitating a corresponding adjustment to the brake hose length to prevent excess slack or interference with other components.

Aesthetic Considerations

Excessively long brake hoses can detract from the overall appearance of the bike, creating a cluttered or untidy look. Shortening the hose can improve the bike’s aesthetics by providing a cleaner and more streamlined appearance.

Preventing Hose Interference

Long brake hoses are prone to tangling, snagging, or getting caught on obstacles while riding, which can lead to accidents or damage to the hose. Shortening the hose reduces the risk of interference, ensuring smoother and safer rides.

Optimizing Hose Routing

Shortening the brake hose allows for more efficient routing, minimizing the risk of kinks or sharp bends that can impede brake fluid flow or compromise braking performance. Proper hose routing can also enhance the bike’s handling and responsiveness.

Personal Preference

Some cyclists prefer a cleaner and more minimalist aesthetic for their bikes, which may involve shortening the brake hose even if it is not strictly necessary for functional reasons. Personalizing the bike’s appearance can enhance the rider’s satisfaction and pride of ownership.

Component Replacement or Upgrade

When you replace or upgrade brake components, such as brake levers or calipers, you may need to adjust the length of the brake hose to ensure compatibility and optimal performance. Shortening the hose may be necessary to accommodate changes in component design or specifications.

Weight Reduction

Although the weight savings from shortening a brake hose are minimal, some cyclists may choose to trim excess length to reduce the overall weight of their bike. Every gram counts for riders seeking maximum performance or competing in weight-conscious disciplines like racing.

Tools and Parts Required

Bike Stand. A bike stand is essential for safely securing your bicycle during maintenance tasks. It provides stability and convenience while you work on your hydraulic disc brake system.
Set of Allen Keys. Allen keys, also known as hex keys, are versatile tools used for tightening or loosening bolts and screws commonly found on Shimano hydraulic disc brakes. They come in various sizes to accommodate different components.
8mm Spanner. The 8mm spanner is specifically used for tightening or loosening bolts and nuts with an 8mm head size, such as the connecting bolt on hydraulic brake levers.
Hydraulic Brake Hose Clamp Blocks. These specialised blocks are designed to securely hold the hydraulic brake hose in place. They prevent it from moving or twisting the hose while you work on it. This ensures accuracy and safety during the hose-shortening process.
Hydraulic Brake Hose Cutters or Utility Knife. Hydraulic brake hose cutters or a utility knife are essential for cleanly and precisely cutting through the brake hose to achieve the desired length. Clean cuts are crucial for the proper installation and functionality of the brake system.
Mole Grips. Mole grips are also known as locking pliers or vise-grips. They are versatile gripping tools used for securely clamping and holding various components in place during maintenance tasks, providing stability and control.
Grease. Grease is used to lubricate threads, seals, and other moving parts, reducing friction and preventing corrosion. It ensures smooth operation and longevity of components, such as the olive and connector insert in hydraulic brake systems.
Mallet or Hammer. You use a mallet or hammer to gently tap or drive components into place, such as the barb into the brake hose or the connector insert into the olive. It provides controlled force without damaging delicate parts.

Parts required

Olive and Connector Insert. The connector insert and olive secure the brake hose to the caliper and lever. The olive creates a tight seal when compressed against the barb, preventing hydraulic fluid leaks and ensuring the proper functioning of the brake system.

Are olives and inserts universal?

Be aware that olives and connector inserts are not universal. The design and size of olives and barbs can vary between different brands and models of hydraulic disc brakes so when you shorten the brake hose, make sure to use the specific olive and barb. Using incompatible or mismatched olives and barbs could result in poor sealing, leaks, or even brake failure.

Remove the rubber cover from the connecting bolt and push it down the hose.

Use the 8mm spanner to undo and remove the connecting bolt from the lever.

Let it slide down the hose.
Grasp the hose and pull it out of the lever.

removing the hose from the lever for shortening Shimano brake hose

Move the hose to where it should reach the brake lever.
Mark it with a tape or a marker pen.

marking the hose for shortening Shimano brake hose

Use the hose clamp blocks and mole grips to secure the hose.
While holding the mole grips use a hydraulic brake hose cutter or a utility knife to cut the hose near the marking point.

Shortening Shimano brake hose with a utility knife

Make sure that you cut it straight in 90 degrees.

Reposition the clamp blocks to expose approximately 2cm of the hose.
Fit the olive.

While holding the mole grips, place the barb in the hose and gently tap it with a hammer.

Note that if the hose has not been cut correctly the top of the connector will not fully touch the end of the hose. This can lead to leaks from the system.

insert fitted into the hose cutted in an angle

Remove the clamp blocks.
Grease the olive and the thread on the connecting bolt.

Slide the hose into the brake lever.
While pushing the hose in screw the connecting bolt.
Tighten the bolt using the 8mm spanner.

Refit the cover.

Check the brake. If it feels spongy then this may indicate air trapped in the hydraulic brake system. If this is the case, you may need to bleed the brake. If you’re not sure how to do this? Check out this great video on how to bleed Shimano hydraulic disc brakes.