How to Properly Maintain Your Shimano SM-BB6700 for Peak Performance

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The Shimano SM-BB6700 [paid link] bottom bracket is a key component of the Ultegra series, known for its smooth performance, durability, and precise engineering. As a threaded external bearing system designed for 68mm and 70mm bottom bracket shells, it supports Hollowtech II cranksets and delivers efficient power transfer. However, maintaining this bottom bracket properly is essential to ensure consistent performance and a long lifespan—especially for road cyclists pushing their bikes in various conditions.

This guide focuses solely on the Shimano SM-BB6700 [paid link] and outlines everything you need to know to keep it running in peak condition.

Understanding the SM-BB6700 Design

The SM-BB6700 [paid link] features a precision-sealed bearing system housed in durable alloy cups. It utilizes Shimano’s signature Hollowtech II interface, meaning the crank spindle is integrated into the right crank arm and runs through the bottom bracket.

The design facilitates easy installation and service access but also demands proper maintenance practices to avoid premature wear or performance degradation, especially under high mileage or poor weather conditions.

Regular Inspection Schedule

Routine inspection of your SM-BB6700 helps catch early signs of wear and prevents unexpected failures. A good maintenance cadence depends on usage and riding conditions.

  • Every 1,000–2,000 km: Perform a visual and tactile check.
  • Every 5,000–8,000 km: Fully remove and inspect the bearings and cups.
  • After wet or dirty rides: Wipe down and assess for contamination.

These timeframes should be adjusted based on whether you ride in harsh environments, such as winter roads or gravel paths.

Cleaning the Bottom Bracket Exterior

Dirt, road grime, and moisture can accumulate around the junction of the shell and cups. Regular external cleaning prevents corrosion and bearing contamination.

To clean:

  • Use a soft cloth with isopropyl alcohol or a degreaser-safe cleaner.
  • Avoid spraying high-pressure water directly at the bottom bracket.
  • Gently wipe the interface between the crank arm and the bearing cup.

It’s essential to inspect for any fluid ingress, especially around the seals.

Proper Lubrication Practices

The SM-BB6700 uses sealed cartridge bearings, meaning the internals are not designed to be serviced or regreased directly. However, there are still critical lubrication points.

  • Apply waterproof grease to the BB shell threads before installation or during servicing.
  • Add a thin layer of anti-seize compound or grease on the bearing cup outer surfaces if the bike is alloy-framed.
  • Lubricate crank spindle interfaces to prevent creaking and galling.

Do not attempt to open the bearing seals unless you’re experienced, as this can damage the sealing system and compromise performance.

Internal Cup and Shell Maintenance

Removing the bottom bracket allows full access to clean the bottom bracket shell. This process is vital when contamination or creaking develops.

Steps include:

  • Fully remove crank arms using Shimano’s Hollowtech II toolset.
  • Unscrew both cups using a bottom bracket tool [paid link] with proper engagement.
  • Clean shell threads with a nylon brush and degreaser.
  • Dry thoroughly and inspect for wear, pitting, or corrosion.
  • Re-grease and reinstall with correct torque: 35–50 Nm.

This procedure ensures proper thread engagement, prevents creaking, and improves bearing longevity.

Signs of Wear and How to Spot Them

The SM-BB6700 bottom bracket is built to last, but like any component, it will eventually wear out. Key indicators of wear include:

  • Creaking or clicking under load: Could signal contaminated bearings or loose installation.
  • Rough rotation: Indicates bearing wear or contamination.
  • Lateral crank play: Suggests bearing cup loosening or wear.

Early detection of these signs can prevent drivetrain inefficiencies and potential damage to other parts.

Protecting Against Corrosion and Seizing

One of the most overlooked aspects of bottom bracket maintenance is corrosion protection—especially in high-moisture or sweat-prone environments.

To prevent seizing:

  • Always use anti-seize on aluminum or titanium frames.
  • Apply extra waterproof grease to the threads on steel frames.
  • Inspect for galvanic corrosion if using dissimilar materials.

Routine removal and reinstallation every 6–12 months can also help break up any seizing or bonding that might occur over time.

When to Replace Your SM-BB6700

The SM-BB6700 is not serviceable in the traditional sense. Once the bearings start to degrade noticeably, replacement is the most practical course of action.

Signs it’s time to replace:

  • Bearing roughness that cannot be cleaned or resolved.
  • Excessive play or looseness even after tightening.
  • Water ingress or rust around the bearing seals.

Replacement intervals vary widely but can range between 10,000 to 20,000 km under typical road use.

Storage and Off-Season Maintenance

If storing your bike for extended periods:

  • Remove crank arms and inspect the bottom bracket for moisture.
  • Clean and regrease the bottom bracket threads.
  • Store the bike in a dry environment, away from temperature fluctuations.

These steps will help extend the lifespan of your SM-BB6700 during periods of inactivity.

FAQs

Q1: Can I regrease the bearings inside the SM-BB6700?
No. The bearings are factory-sealed and not designed for internal servicing. If rotation feels rough, replacement is recommended.

Q2: What torque should I use when installing the SM-BB6700?
Shimano recommends a torque of 35–50 Nm for bottom bracket cup installation.

Q3: Can I use threadlocker instead of grease on the BB threads?
No. Shimano recommends grease or anti-seize to allow for future removal and to prevent seizing or corrosion.

Q4: How do I know if the creaking noise is from the bottom bracket?
Isolate the noise by checking crank arm bolts, chainring bolts, and pedal threads. If creaking continues only under load, the bottom bracket may be the culprit.

Q5: How long does the SM-BB6700 typically last?
Under average road cycling conditions, it can last between 10,000 to 20,000 km with proper maintenance.

Q6: Is the SM-BB6700 compatible with carbon frames?
Yes, provided the frame uses an English or Italian-threaded BB shell. Use proper torque and install with anti-seize to prevent bonding with carbon.

Conclusion

Proper maintenance of the Shimano SM-BB6700 bottom bracket is crucial for peak drivetrain performance, longevity, and noise-free riding. From regular inspections and cleaning to understanding when replacement is necessary, these practices ensure that your bottom bracket remains a reliable foundation for every ride.