The Shimano BR-6800 [paid link] brake caliper, part of the Ultegra 6800 series, is known for its reliable stopping power and precise modulation. However, like all mechanical components, these brakes can experience issues if not properly installed, adjusted, or maintained. This article explores the most common problems that occur with the BR-6800 [paid link] and provides practical, detailed solutions for each.
Brake Lever Feel Is Spongy or Soft
One of the most reported issues with BR-6800 [paid link] brakes is a mushy or inconsistent feel at the lever. This often results from cable tension problems or contamination in the brake path.
Start by inspecting the brake cable for excessive stretch or housing compression. Over time, cables may elongate, and housing can compress, reducing the system’s effectiveness. Re-tension the cable by releasing it from the caliper, pulling it taut, and re-clamping it securely.
Additionally, check for any contamination such as water, dirt, or corrosion inside the cable housing. Replace the housing and inner cable if any resistance is felt during movement. Lubricating new cables with a light grease before installation helps preserve responsiveness and smooth operation.
Brakes Rubbing on the Rim
Rim rub is typically caused by poor centering of the caliper or a misaligned wheel. If your BR-6800 brakes are making contact with the rim while riding, it’s critical to check the caliper’s position.
Use the centering screw on the top of the brake caliper to adjust the spring tension on either side. Turning this screw will help re-center the arms symmetrically. Also, ensure the wheel is fully seated in the dropouts and correctly tensioned through the quick release or thru-axle.
Another common culprit is warped rims. Check the rim for lateral true. A simple wheel truing session may resolve contact that occurs only at one portion of the wheel’s rotation.
Weak Braking Power
If your BR-6800 calipers feel underpowered, several factors could be at play. Worn brake pads, improper pad alignment, or insufficient cable tension often contribute to this issue.
Begin with a visual inspection of the brake pads. Shimano recommends replacing pads when the wear line is no longer visible or the grooves are worn smooth. Misaligned pads that don’t fully contact the rim can also reduce power. Adjust the pad angle and height so that the entire pad contacts the braking surface simultaneously.
Ensure that cable tension is sufficient. When squeezing the lever, the brake arms should engage the rim firmly at about one-third of the lever’s full travel. If the lever can be pulled to the bar without full braking engagement, increase the tension.
Noisy Braking—Squealing or Screeching
Noise during braking is not only annoying but also a sign of inefficiency. The BR-6800 system may develop squealing if the pads are contaminated, misaligned, or too far from the rim.
Start by cleaning the rim surface and brake pads with isopropyl alcohol to remove any oil, grease, or road grime. Next, check the brake pad toe-in. This refers to the front of the brake pad contacting the rim slightly before the rear. Toe-in helps reduce vibration, which often causes noise. Adjust the mounting angle using a 5mm hex wrench.
If the noise persists, inspect the pad material. Some pads harden over time or glaze due to heat, resulting in poor contact and noise. Replace them if needed.
Brake Arms Not Releasing Evenly
If one arm of the BR-6800 caliper stays closer to the rim after braking, it could be a spring tension imbalance or debris at the pivot.
Use the small centering screw to rebalance spring tension. Tightening this screw on one side increases the spring force, helping both arms retract equally.
Clean and lubricate the caliper pivot bolts periodically. Dirt and grime can prevent smooth operation, especially after riding in wet conditions. Do not over-lubricate—use a light grease and wipe off any excess.
Brake Pads Wearing Unevenly
Uneven pad wear may result from misalignment or improper toe-in settings. Check that the pad is mounted parallel to the rim surface and not tilted.
Use a caliper alignment tool or a credit card shim to achieve consistent toe-in. Pads should contact the rim evenly across their surface during braking. Misaligned pads not only wear out faster but also diminish stopping power and control.
Cable Friction Reducing Braking Efficiency
Internal cable routing in modern bikes can lead to increased friction if not maintained. If your brake lever feels tight or sticky, inspect all housing bends for tight angles or kinks.
Replacing the cables and using compressionless housing, especially for tight frame geometries, can significantly improve feel. Always lubricate new cables lightly before installation to reduce drag inside the housing.
Conclusion
Shimano BR-6800 brakes offer exceptional performance when properly installed and maintained. However, even minor setup errors or component wear can significantly reduce braking efficiency and safety. By addressing common issues such as poor centering, spongy lever feel, noise, and reduced power, riders can restore and maintain peak braking performance.
Regular inspections and timely maintenance not only prevent bigger problems but also extend the life of your braking system. Stay ahead of issues by developing a maintenance routine and addressing symptoms early for optimal safety and confidence on the road.
FAQs About Shimano BR-6800 Brake Troubleshooting
1. Why are my BR-6800 brakes rubbing the rim even after adjustment?
This usually indicates a centering issue or a misaligned wheel. Check the brake centering screw and ensure the wheel is fully seated in the dropouts.
2. What causes squeaky noises with the BR-6800 brakes?
Squealing is typically caused by contaminated pads, improper toe-in, or glazed braking surfaces. Cleaning and realignment usually resolve the issue.
3. How can I fix a spongy feel in my BR-6800 brake levers?
Check cable tension and look for housing compression or corrosion. Replace cables and housings if needed to restore firmness.
4. When should I replace the brake pads on the BR-6800?
Pads should be replaced when the wear indicator is no longer visible or the surface becomes hard and glazed.
5. Can I use carbon rims with the BR-6800 calipers?
Yes, but only with appropriate carbon-specific brake pads. Standard pads can damage carbon rims and compromise braking.
6. How often should I lubricate the BR-6800 brake pivots?
Light lubrication every few months or after wet rides will keep the pivots functioning smoothly without attracting excess dirt.