Maximizing Performance: How to Keep Your SM-BB6700 Running Like New

Posted on
in No category

The Shimano SM-BB6700 [paid link] bottom bracket is designed to deliver efficient power transfer, reliable operation, and longevity under high-performance road cycling conditions. However, to ensure this component maintains its top-tier functionality over time, it must be installed correctly, maintained with precision, and regularly monitored for early signs of wear. This guide offers a complete walkthrough for maintaining peak performance in the SM-BB6700 [paid link], focusing exclusively on this model.

Understanding the SM-BB6700: Technical Overview

The SM-BB6700 [paid link] is part of Shimano’s Ultegra series and features outboard steel cartridge bearings encased in threaded aluminum cups. Designed for use with Hollowtech II cranksets, this bottom bracket is known for its low friction, durability, and compatibility with English-threaded (BSA) 68mm bottom bracket shells. It requires precise torque and proper sealing to ensure reliable performance.

Initial Installation Quality and Its Impact on Longevity

Proper installation sets the foundation for the SM-BB6700’s long-term performance. Misaligned threads, over-torquing, or contamination during assembly can lead to premature wear, creaking, or resistance.

  • Thread Preparation: Clean and inspect the frame’s bottom bracket shell thoroughly. Apply anti-seize compound (not grease) to the threads to prevent galling and corrosion.
  • Cup Alignment: Hand-thread both cups first to avoid cross-threading. The drive side should be turned counterclockwise (reverse-threaded), while the non-drive side threads in clockwise.
  • Torque Settings: Use a torque wrench [paid link] to tighten each cup to Shimano’s specification of 35–50 Nm. Incorrect torque often leads to noise or bearing stress.

A meticulous approach during this stage greatly reduces future issues.

Routine Maintenance to Extend Bearing Life

Even though the SM-BB6700 uses sealed cartridge bearings, maintenance remains vital to performance, particularly for riders in wet, muddy, or dusty environments.

  • Inspection Interval: Every 2,000–3,000 kilometers, remove the crankset to inspect for water intrusion or grime build-up. This helps prevent corrosion and ensures smooth operation.
  • Cleaning Procedure: Use a soft brush and mild degreaser to clean around the bearing cups. Avoid direct water pressure, especially near the bearing seals.
  • Lubrication: Apply a light coat of waterproof grease around the cup exterior and crank spindle interface. While the bearings are sealed, external lubrication helps prevent creaking.

Keeping the bottom bracket area clean and dry is the most effective way to reduce friction and extend service life.

How to Identify Wear and Performance Loss

Early signs of SM-BB6700 degradation are subtle but detectable. Knowing what to look for can prevent sudden failures during a ride.

  • Creaking Under Load: If you hear consistent creaking while pedaling, inspect the crank spindle and cup threads. A lack of grease or poor torque can be the cause, but worn bearings are another possibility.
  • Play or Looseness: Movement in the crank arms when rocked laterally may indicate bearing wear or improperly torqued cups.
  • Rough Rotation: Remove the crank and rotate the spindle inside the bearings manually. Any gritty or notchy feel indicates internal contamination or bearing failure.

Documenting these symptoms helps track performance trends over time.

Bearing Replacement or Bottom Bracket Swap

While Shimano does not officially endorse servicing the sealed bearings in the SM-BB6700, experienced mechanics can identify when it’s time to replace the unit.

  • Average Lifespan: Under optimal conditions, the SM-BB6700 can last upwards of 10,000 kilometers. In wet or aggressive conditions, expect closer to 5,000–7,000 km.
  • Replacement Signs: If the bottom bracket makes noise despite cleaning and correct torque, or if rotation feels stiff or gritty, it’s time to replace the unit.
  • Removal Technique: Use a Hollowtech II-specific bottom bracket tool [paid link] to remove each cup. Always re-clean and inspect the shell before installing a new SM-BB6700.

When swapping the unit, always replace both cups—never mix old and new components.

Optimization Tips for Competitive Riders

For cyclists focused on competitive edge, minimizing friction and maximizing stiffness is key. While the SM-BB6700 performs admirably, some specific adjustments can optimize its output.

  • Frame Face Facing: Ensure the frame’s bottom bracket shell is properly faced. Misaligned faces can cause uneven bearing load and premature wear.
  • Crankset Preload Adjustment: Use Shimano’s plastic preload cap and adjust until resistance just begins to increase—then back off slightly. Over-tightening increases drag and reduces bearing life.
  • Upgrade Consideration: Riders seeking marginal gains may explore ceramic bearing alternatives. However, these upgrades must maintain compatibility with Hollowtech II standards and the SM-BB6700 cup size.

These tuning techniques ensure minimal energy loss and consistent performance.

Storage and Off-Season Care

Proper storage during off-seasons is often overlooked. Moisture accumulation and frame condensation can damage even sealed components.

  • Clean Before Storage: Remove the crankset, clean the SM-BB6700 thoroughly, and inspect the bearing condition.
  • Lubricate Interfaces: Apply grease to the crank spindle and cup interface to create a barrier against moisture.
  • Humidity Control: Store the bike in a dry, temperature-controlled space to prevent corrosion inside the shell.

This preparation ensures your bottom bracket stays race-ready through the offseason.

Final Thoughts

The Shimano SM-BB6700 remains a dependable bottom bracket choice for road cyclists who value durability, efficiency, and simplicity. Keeping it running like new requires more than just riding—it demands attentive maintenance, periodic inspection, and methodical cleaning. Whether you’re logging daily training miles or gearing up for a gran fondo, a properly maintained SM-BB6700 is central to peak drivetrain performance.

Frequently Asked Questions

1. How often should I service the SM-BB6700?
Every 2,000–3,000 kilometers is a safe interval for inspection. In wet conditions, consider checking more frequently.

2. Can the bearings inside the SM-BB6700 be replaced separately?
Shimano does not offer replacement bearings for this model. The entire unit is replaced when bearings are worn.

3. Why is my bottom bracket creaking after installation?
This often stems from insufficient torque, lack of grease, or contamination. Reinstall using anti-seize and correct torque.

4. Is the SM-BB6700 compatible with all Hollowtech II cranks?
Yes, it’s compatible with all Shimano Hollowtech II road cranks and other cranks using the same spindle diameter.

5. What is the torque specification for installing the SM-BB6700 cups?
Torque both cups to 35–50 Nm using a Hollowtech II compatible tool.

6. Should I grease or anti-seize the threads during installation?
Use anti-seize on the threads to prevent galling and future removal issues, especially in metal-threaded frames.