The Shimano BR-6700 [paid link] brakes, part of the second-generation Ultegra 6700 series, represent a solid evolution in dual-pivot caliper braking systems. Designed for performance road bikes, these brakes feature improved arm design and increased clearance for better modulation and control. However, achieving optimal performance depends heavily on proper compatibility with other drivetrain and braking components.
This guide outlines the key compatibility considerations for the Shimano BR-6700 [paid link] brakes, helping you identify what integrates smoothly and what combinations can undermine braking efficiency.
Understanding BR-6700 Brake Design and Specifications
Before diving into compatibility, it’s essential to understand what defines the BR-6700 [paid link] brakes:
- Type: Dual-pivot side-pull caliper brakes
- Mounting: Standard recessed nut (for traditional road bike frames)
- Reach: 39-49 mm
- Pad Type: Cartridge-style road pads (Shimano R55C series)
- Intended Use: Road cycling with caliper brake frames and standard road rims
With these parameters in mind, compatibility assessments should prioritize rim width, cable pull ratios, brake lever mechanics, and mounting constraints.
Frame and Fork Compatibility: Fitment Constraints
The BR-6700 uses a standard reach of 39-49 mm, which fits most modern and classic road bike frames designed for caliper brakes. However, fitment issues can arise in the following cases:
- Aero frames: Some aero road frames require direct-mount brakes or have hidden cable routing that doesn’t match BR-6700’s mechanical setup.
- Wide tire clearance: Frames designed for wider tires (e.g., 28 mm and above) may experience limited clearance with BR-6700 calipers, especially if rim width is also increased.
- Direct-mount incompatibility: The BR-6700 is not compatible with direct-mount brake bosses, which require a completely different brake architecture.
Always verify the brake bridge and fork crown bolt distance, as well as tire clearance, to ensure these calipers can operate without interference.
Brake Lever Compatibility: Mechanical Pull Ratios
One of the most critical compatibility factors for the BR-6700 brakes is brake lever matching. Since they are designed for Shimano STI levers with Super SLR (Shimano Linear Response) technology, mismatches in cable pull can result in poor braking feel or lever throw.
Ideal Levers for BR-6700:
- Shimano ST-6700 [paid link] (Ultegra)
- Shimano ST-6600 (previous generation, with some reduced performance)
- Shimano ST-5700 [paid link] (105 10-speed, same cable pull ratio)
- Shimano ST-7900 [paid link] (Dura-Ace 10-speed)
Potential Compatibility Failures:
- Modern 11/12-speed levers: Shimano redesigned cable pull for newer generations; although still functional, the braking feel may be compromised.
- Non-Super SLR levers: Older or third-party levers (e.g., Tektro or vintage Campagnolo) may not provide adequate leverage or modulation.
To ensure peak performance, stick with Shimano’s Super SLR-compatible levers from the same generation or those confirmed with similar mechanical pull.
Wheel and Rim Compatibility: Width and Surface Considerations
The BR-6700 brakes were developed around traditional road wheelsets with rim widths of approximately 19–21 mm (external). Using modern wide rims (23–25 mm external) can introduce two main issues:
- Pad contact area misalignment: The curvature of wider rims can prevent full pad contact, reducing braking power and causing uneven wear.
- Pad-to-rim clearance: Wide rims combined with large tires may exceed the caliper’s opening width, making wheel removal more difficult or impossible without deflating the tire.
Additionally, these brakes are not compatible with disc brake systems or any rim requiring cantilever, V-brake, or U-brake architecture.
For braking surface compatibility, the BR-6700 pads are optimized for aluminum rims. If using carbon rims, install carbon-specific brake pads compatible with Shimano holders (e.g., R55C4 for carbon). Never use aluminum-specific pads on carbon rims.
Brake Pad Compatibility: Cartridge Systems and Alternatives
The BR-6700 calipers use Shimano’s R55-series brake pads in a cartridge format, offering easy replacement and customization.
Compatible Pad Inserts:
- Shimano R55C3 and R55C4 (for alloy rims)
- R55C4 Carbon (for carbon rims)
- Kool-Stop Dura2 inserts (third-party, widely compatible)
Avoid using non-cartridge pads or pads intended for V-brakes, as they do not fit and compromise both safety and braking effectiveness.
Cable and Housing Compatibility
These brakes require standard road brake cables and housing. While mechanical cable pull ratios are widely standardized, using high-quality, low-friction cable systems (e.g., polymer-coated or compressionless housing) can significantly improve lever feel and response time.
Avoid:
- MTB-specific housing (thicker, more resistant)
- Cheap steel cables with rough finishes (increase drag)
Upgrading to high-performance cables enhances both compatibility and braking control.
Drivetrain Compatibility: What to Know
Though part of a drivetrain group, the BR-6700 brakes operate independently of cassette or derailleur systems. However, cable routing, lever integration, and aesthetic matching often guide component selection.
Works well with:
- Shimano 10-speed drivetrains (Ultegra 6700, 105 5700, Dura-Ace 7900)
- Matching levers for seamless appearance and mechanical integration
While mixing with 11-speed or newer Shimano groups is physically possible, the altered lever pull may reduce brake responsiveness.
Common Compatibility Pitfalls to Avoid
- Mixing with SRAM or Campagnolo levers: Even when mechanically compatible, differences in cable pull and modulation design often yield poor brake performance.
- Assuming carbon rim compatibility: Not all pads are safe for carbon; incorrect usage can damage rims and reduce braking power.
- Fitting on non-road frames: Cyclocross, gravel, and hybrid frames typically require cantilever or disc brakes—not side-pull calipers like the BR-6700.
Always check manufacturer specifications and perform a full dry-fit test before committing to a mixed-component build.
Conclusion: Best Practices for BR-6700 Brake Compatibility
To ensure Shimano BR-6700 brakes function at their best, match them with compatible levers (preferably from the same generation), use standard road rims with correct width, and avoid non-standard frame geometries. Their performance excels within the 10-speed Shimano ecosystem, offering consistent and predictable braking when installed correctly.
Stick with:
- Shimano 10-speed Super SLR levers
- Aluminum rims or carbon with proper pads
- Standard reach road frames (39–49 mm)
Avoid:
- Wide gravel rims and tires
- Modern levers with revised pull ratios
- MTB or disc-specific frames
Correct compatibility choices will preserve braking efficiency and prevent premature wear or performance issues with your BR-6700 setup.