Crimping pliers

On bicycles, crimping pliers are used wherever cables need to be neatly terminated or lines tightly connected — from simple Bowden cables to hydraulic lines on disc brakes.

What is a crimping tool used for on a bicycle?

crimp cable end ferrules

The most common application in the home workshop: After shortening, the open end of a Bowden cable or gear cable is fitted with a small aluminum sleeve (cable end sleeve, also called an "end cap"). Without this sleeve, the inner cable frays within a short time—threading it the next time the cable is replaced becomes a test of patience, and individual wires can prick the skin.

A crimping tool securely crimps this sleeve in seconds. Alternatively, it can be done with regular pliers in a pinch, but the result is rarely as clean.

Hydraulic lines for disc brakes

On hydraulic disc brakes (e.g., with mineral or DOT fluid), the lines are connected using olives and banjo bolts (barb system) or with pre-assembled fittings. Special crimping pliers—usually with dies specific to the brake manufacturer—squeeze the olive onto the line, creating a permanent, pressure-tight connection. This application is more demanding and requires the correct tool for the specific brake system.

Other applications

• Cable lugs and connecting sleeves for electrical cables (e.g. on e-bike batteries or lighting systems)
• Securing clamps on luggage racks or brake cable holders
• Nipple end caps on spokes (rare, but possible)

Types of crimping pliers

Not every crimping tool is suitable for every task. On bicycles, two categories are particularly relevant:

Universal pliers for cable end ferrules

Inexpensive models with a simple crimp notch — sufficient for crimping cable ferrules onto internal and shift cable housings. Often available as a set with a cable cutter. Perfectly adequate for occasional use in a home workshop.

Combination tools (cable cutter + crimping pliers)

Many bicycle-specific cable cutters have an integrated crimping notch. This allows the cable to be cut and the end sleeve crimped in one go — practical for frequent Bowden cable replacements.

Die crimping pliers for hydraulic lines

Hydraulic brake lines require a crimping tool with interchangeable dies (inserts) that are precisely matched to the outer diameter of the olive and the fitting. Incorrect dimensional tolerances here mean either leaks or pinched lines—both of which are safety hazards. These tools are more expensive and are generally only used in professional workshops or by highly experienced DIY mechanics.

What you should pay attention to when buying

A simple combination tool from a bicycle shop is sufficient for crimping cable end ferrules . Pay attention to:
- A cleanly milled crimp notch that deforms the sleeve into a round shape (does not squeeze it into an oval shape)
- Integrated cutting notch for inner and shift cable cables
- Carbide cutting blade to ensure the cable is cleanly cut without fraying.

For hydraulic lines, you should check:
- Which brake system is installed (different olive diameters depending on the manufacturer)
- Whether the tool comes with compatible dies for this system or can be retrofitted
- Whether the device ensures a defined crimping pressure (often not guaranteed with cheap models)

Crimping pliers vs. regular pliers: Is the special tool worth it?

For cable end ferrules, you can use flat-nose pliers or combination pliers in a pinch—the result won't look as neat, but it will hold. However, with regular maintenance and several cable replacements per year, the special tool, starting at around €10–15, quickly pays for itself.

The opposite is true for hydraulic lines : an incorrectly crimped olive can lead to pressure loss or uncontrollable brake failure. Here, the right tool is not a matter of convenience, but of safety. Anyone who doesn't have a suitable die crimping tool should leave this work to a professional workshop.

Tips for use

• Position the sleeve correctly before crimping: The end sleeve must be completely pushed over the cable end before you apply the pliers — otherwise the crimp will only grip the sleeve, not the cable.
• One crimp is sufficient: repeated crimping weakens the material. If the connection is not secure after the first crimp, it's better to use a new sleeve.
• Cut the cable cleanly before crimping: A ragged cut makes threading it into the ferrule more difficult. A good cable cutter provides the necessary clean cut.
• Pay attention to the correct ferrule size: Ferrules are available in various inner diameters for brake and gear cables. A ferrule that is too large will not fit securely, and one that is too small cannot be crimped on.

Conclusion

Crimping pliers aren't a glamorous tool—but they make all the difference between a neatly finished repair and a frayed cable end. A simple combination model with cutting and crimping functions is essential for any home workshop . Anyone servicing hydraulic brakes themselves needs the appropriate die tool—or should take the job to a professional.