The Shimano BR-6700 [paid link] brake calipers, part of the Ultegra 6700 groupset, are a high-performance rim brake option popular among road cyclists for their consistent modulation and reliable stopping power. However, like any mechanical system, they can present issues if not correctly installed, maintained, or adjusted. This guide will walk you through the most frequent problems cyclists encounter with the BR-6700 [paid link] brakes and how to resolve them effectively.
Brake Caliper Misalignment
One of the most frequently reported issues with the BR-6700 [paid link] is caliper misalignment, where the arms do not center properly over the rim. This misalignment can lead to uneven braking, pad rub, and poor modulation.
Solution:
Begin by loosening the mounting bolt slightly while holding the brake in a centered position over the rim. Use the centering screw located on the top of the caliper arm to fine-tune the centering. Turn the screw clockwise or counterclockwise until both pads are equidistant from the rim. Tighten the mounting bolt securely, ensuring the caliper does not shift from the aligned position.
Insufficient Braking Power
Riders may notice reduced braking performance, often caused by either worn brake pads, contamination, or improper cable tension. On a descending ride, this becomes especially noticeable.
Solution:
Check the condition of the brake pads. If they’re heavily worn or glazed, replace them with new Shimano-compatible pads. Clean the braking surface of the rim using isopropyl alcohol and a clean cloth. Inspect the brake cable for excess slack or corrosion. Adjust the barrel adjuster to increase tension or replace the cable if necessary.
Brake Pads Rubbing the Rim
Brake rub is another common issue, particularly after wheel changes or minor impacts that affect the brake alignment. Rubbing can cause unnecessary resistance and noise.
Solution:
Ensure the wheel is properly seated in the dropouts. Re-center the brake caliper using the centering screw. Then, adjust the pad alignment. The pads should strike the rim flatly without contacting the tire or hanging too low. Toe-in the pads slightly—where the front edge contacts the rim slightly before the rear edge—to minimize squeal and improve modulation.
Squealing or Noisy Braking
Noisy braking is often linked to pad misalignment, dirty rims, or incompatible pad material. The BR-6700 is sensitive to pad alignment and toe-in settings.
Solution:
Ensure that pads are toed-in correctly by placing a small piece of folded paper between the rear of the pad and the rim while tightening. Clean the rims and pads thoroughly. If noise persists, try switching to a different compound pad (e.g., softer compound for aluminum rims).
Brake Lever Feels Spongy
A spongy lever feel can make the brake response feel delayed or unpredictable. This is generally due to poor cable tension or excess cable housing friction.
Solution:
Inspect the entire cable system. If the housing is old, frayed, or kinked, replace both the inner cable and housing. Lubricate the cable lightly with a PTFE-based lube before inserting it into the housing. Re-adjust tension at the barrel adjuster and make final refinements at the anchor bolt if needed.
Pads Not Returning Properly
If the brake pads fail to return to their resting position after braking, it could be due to corroded pivots or over-torqued mounting hardware.
Solution:
Loosen the caliper bolt slightly and check for free movement. Apply a small amount of grease or light lubricant to the pivot points, taking care not to contaminate the pads or rims. If the caliper remains sluggish, remove it from the frame for a full inspection and cleaning.
Cable Friction and Drag
High friction within the cable housing reduces responsiveness and can cause uneven actuation of the calipers. Over time, grime buildup or poor routing leads to degraded performance.
Solution:
Replace the cable and housing with new components. Opt for compressionless housing for better performance. Route the cables carefully, avoiding sharp bends and ensuring smooth movement through each stop. Apply grease or use lined housing for smoother cable action.
Uneven Pad Wear
Pads wearing unevenly can signal misalignment or uneven arm tension. This can compromise braking efficiency and may damage the rim over time.
Solution:
Check that the pad sits parallel to the braking surface and doesn’t angle inward or outward. Re-align the pads as necessary. If wear persists on one side, inspect and adjust the spring tension using the centering screw. Ensure both arms move symmetrically when actuated.
Brake Arms Not Moving Equally
If one arm moves more than the other, braking feels inconsistent. This usually results from unbalanced spring tension.
Solution:
Turn the centering screw to equalize the arm movement. If the screw is already at its limit, reset the caliper by loosening the mount, re-centering it manually, then tightening while holding the correct position. Test several times while adjusting incrementally.
Brake Caliper Feels Loose or Shifts While Braking
Loose mounting bolts or improperly torqued components can cause the caliper to shift under load, reducing braking reliability.
Solution:
Remove the caliper and clean the mounting surface. Apply a small amount of grease to the bolt threads and re-install the caliper. Tighten the center bolt to the specified torque—typically 6-8 Nm for BR-6700—using a torque wrench [paid link].
Conclusion
Shimano BR-6700 brakes offer reliable performance, but only when set up and maintained properly. Understanding and addressing these common issues ensures your braking remains safe, responsive, and consistent. Regular inspections, precise adjustments, and high-quality components are key to keeping your BR-6700 brakes in optimal condition.