Replacing the brake cables on your Shimano BR-6700 [paid link] caliper brakes is a critical maintenance task that restores braking precision, responsiveness, and safety. Over time, cables stretch, fray, corrode, or suffer from housing contamination, causing a decline in lever feel and braking efficiency. This guide provides a structured, technical walkthrough for replacing both the inner cable and outer housing on BR-6700 [paid link] brakes, ensuring your Ultegra-level [paid link] road bike performs at its best.
Tools Required
- 4mm and 5mm hex keys [paid link]
- Cable cutters (for inner cable and housing)
- New stainless steel brake cables (compatible with Shimano road levers)
- Brake cable housing (compressionless preferred)
- Cable ferrules and end caps
- Needle-nose pliers
- Torque wrench [paid link] (optional but recommended)
- Light grease or PTFE lubricant
Understanding the Shimano BR-6700 [paid link] Cable System
The BR-6700 brakes are part of the Shimano Ultegra 6700 series and are designed for dual-pivot, short-reach caliper brakes. The system uses standard road bike brake cable routing with compatibility across Shimano STI levers. BR-6700 calipers rely heavily on proper cable tension and clean housing to deliver their signature crisp, linear braking power. Neglecting cable maintenance can lead to spongy lever feel, reduced modulation, and even brake failure.
Preparation Before Cable Replacement
Before beginning the replacement, shift your brake lever to the open position and inspect the full length of your current brake housing. Take note of how it’s routed through the frame or under the bar tape. If you’re re-wrapping your handlebars or doing a full rebuild, now is the ideal time to replace both the housing and cables together. Always match housing length and routing to the original to avoid introducing excessive friction or slack.
If you’re only replacing the inner cable and reusing the housing, inspect the interior for rust or compression. Any signs of dirt ingress or deformities warrant full replacement.
Removing the Old Brake Cable
Start at the brake lever by unhooking the brake cable from the caliper arm. Use a 5mm hex key [paid link] to loosen the cable pinch bolt on the BR-6700 arm. Once free, retract the cable through the lever and gently pull it out, noting any resistance that might indicate frayed wires or kinked housing.
Remove any housing sections if you’re doing a full swap. For bikes with internal routing, thread the cable through carefully, ensuring it doesn’t snag or scrape.
Installing the New Brake Cable
Grease the new stainless inner cable lightly along its full length to reduce friction. Insert it into the STI brake lever and feed it through until it exits cleanly at the caliper end. If using new housing, cut each segment to match the original length, ensuring smooth, uninterrupted curves.
Fit ferrules on the ends of the housing segments. Where applicable, seat them firmly into cable stops on the frame. Insert the inner cable through the new housing and ensure it glides without binding. If friction occurs, double-check for misalignment or poorly cut housing ends.
Connecting to the BR-6700 Caliper
Thread the cable through the clamping mechanism on the BR-6700 arm. Pull the cable tight by hand, then apply the brake lever gently to center the brake arms and align the pads. While the pads are in contact with the rim, secure the pinch bolt using a 5mm hex key [paid link]. If available, use a torque wrench [paid link] to tighten to Shimano’s recommended spec of 6–8 Nm.
Trim the excess cable, leaving about 3–4 cm past the pinch bolt. Crimp on a cable end cap using needle-nose pliers to prevent fraying.
Final Adjustment and Brake Tuning
Squeeze the brake lever to assess lever travel and brake responsiveness. If the lever pulls too far before engaging, adjust the barrel adjuster on the caliper or lever to add tension. Conversely, if the brakes feel too tight or drag, release some tension and re-center the caliper.
Ensure the brake pads are aligned parallel to the rim braking surface, with no toe-in or heel-in unless specifically desired for noise reduction. Brake pad wear indicators should still be visible.
Test the brake several times under load. The BR-6700’s dual-pivot design provides strong return spring force, so the calipers should snap back crisply when released. If not, inspect the spring tension screw and adjust slightly to balance the arms.
Performance Benefits of New Brake Cables on BR-6700
New cables can dramatically improve brake modulation and reduce hand fatigue. The BR-6700 calipers respond best to consistent input from a clean, friction-free cable system. Riders switching from corroded or stretched cables will notice a firmer lever feel, more predictable braking response, and improved stopping power—especially in wet conditions.
Replacing cables regularly—ideally once a year for high-mileage riders—ensures your BR-6700 brakes remain as responsive as the day they were installed.
Compatibility Considerations
The BR-6700 is compatible with all Shimano road STI levers from the same generation (6700/6600) and backward-compatible with older 10-speed Shimano drivetrains. Use only standard-diameter road brake cables (1.6mm) and housing designed for brake systems (not shift housing). Avoid mixing brands unless they are explicitly compatible, as differences in cable head shape or housing compression can affect brake feel.
FAQs: BR-6700 Brake Cable Replacement
Q1: How often should I replace brake cables on the BR-6700?
A: Annually for frequent riders or whenever you notice reduced performance, fraying, or corrosion.
Q2: Can I reuse the housing when replacing the inner cable?
A: Yes, if it’s clean and undamaged. But full replacement is recommended for best performance.
Q3: What type of cable housing is best for BR-6700?
A: Compressionless brake housing provides better braking force and reduced squishiness at the lever.
Q4: My new cable feels sticky. What went wrong?
A: Likely causes include kinks in the housing, sharp bends, or lack of lubrication inside the housing.
Q5: Can I use Shimano 105 cables with BR-6700?
A: Yes, all Shimano road brake cables are cross-compatible with Ultegra components.
Q6: What if my lever pulls all the way to the bar after installation?
A: You may have low cable tension or brake pads set too far from the rim. Re-check installation and adjust tension accordingly.
Conclusion
Replacing the brake cables on your Shimano BR-6700 brakes is a straightforward yet essential task that directly impacts your safety and ride quality. With the right tools and attention to detail, even amateur mechanics can restore precise brake feel and reliable stopping power. Regular cable maintenance not only enhances performance but also extends the life of your entire braking system.