The Shimano SM-BB6700 [paid link] bottom bracket, part of the Ultegra series, is engineered for performance-focused road cyclists. Its external cup design and Hollowtech II technology offer a balance of stiffness, weight reduction, and durability. Whether you’re upgrading or replacing your bottom bracket, deciding between DIY installation and professional service is crucial. This article explores both approaches to help you make the right choice for your SM-BB6700 [paid link] setup.
Understanding the SM-BB6700 [paid link] Bottom Bracket
The SM-BB6700 is a threaded bottom bracket designed specifically for Shimano’s Hollowtech II cranksets. It uses precision-sealed cartridge bearings housed in alloy cups and fits standard BSA (68mm or 73mm) bottom bracket shells. Known for its smooth rotation and longevity, it remains a go-to for serious riders.
However, installation quality heavily influences performance. Bearing misalignment, over-torquing, or contamination during setup can lead to premature wear or creaking. These risks are central to the DIY versus professional debate.
DIY Installation: What You Need to Know
Installing the SM-BB6700 yourself can be satisfying and economical. However, it requires mechanical competence and attention to detail.
Tools Required:
- Hollowtech II bottom bracket tool [paid link] (e.g., TL-FC32 [paid link] or TL-FC36 [paid link])
- Torque wrench [paid link] with 1/2″ drive and torque specifications
- Bottom bracket facing tool (optional but recommended)
- Grease or anti-seize compound
- Allen keys [paid link] (for crank arm installation)
Pros of DIY Installation:
- Cost Savings: No labor fees, ideal for those with multiple bikes or frequent component swaps.
- Learning Experience: Enhances mechanical knowledge and confidence.
- Convenience: No scheduling or transport required—install at your pace.
Potential Risks:
- Thread Damage: Cross-threading alloy cups into steel shells can cause irreparable damage.
- Misalignment: Without proper shell preparation, bearings may not seat evenly.
- Over-Tightening or Under-Tightening: Torque precision is essential; incorrect values can cause creaking or loosening.
- Contamination: Even small amounts of dirt or metal shavings can compromise bearing life.
If you’re a seasoned home mechanic with the correct tools and environment, DIY installation can be a safe route. But if you lack confidence or precision tools, consider professional help.
Professional Installation: The Case for Expert Help
Taking your SM-BB6700 to a professional bike mechanic has its benefits—especially for riders concerned with long-term performance.
Advantages:
- Proper Facing and Tapping: Shops have bottom bracket facing tools to ensure shell alignment and clean threads.
- Torque Accuracy: Mechanics use calibrated torque wrenches and follow manufacturer specs.
- Component Inspection: Technicians will inspect crank arms, shells, and threads for wear or damage before installation.
- Time Savings: What may take a home mechanic an hour could take a professional 15 minutes.
When Professional Installation Is Recommended:
- You are unfamiliar with bottom bracket standards or torque specs.
- Your frame has not been recently faced or tapped.
- You’re installing into a carbon or high-end alloy frame.
- You’ve previously experienced creaking or premature wear.
- You’re unsure of shell cleanliness or thread integrity.
Professional service ensures optimal bearing alignment, torque, and longevity—crucial for drivetrain efficiency and silence.
Key Differences: DIY vs. Professional Installation
| Aspect | DIY Installation | Professional Installation |
|---|---|---|
| Cost | Low (tool investment needed) | Medium (labor cost applies) |
| Required Tools | Multiple specialized tools | All tools included in service |
| Accuracy & Reliability | Depends on skill and prep | Consistently high |
| Time Investment | Higher learning curve | Quick and efficient |
| Risk of Setup Errors | Moderate to high | Very low |
| Shell Preparation | Optional or unavailable | Standard procedure |
Long-Term Considerations for SM-BB6700 Owners
No matter who installs your bottom bracket, long-term performance depends on correct maintenance:
- Regularly inspect for creaks or movement.
- Re-torque if necessary after initial break-in.
- Periodically check crank preload and re-grease threads.
- Clean shell and bearing faces when replacing cranks.
Whether installed DIY or professionally, the SM-BB6700 can deliver years of quiet, smooth service—if set up and maintained properly.
Conclusion: Which Route Should You Take?
The choice between DIY and professional SM-BB6700 installation boils down to your experience, confidence, and available tools. If you’re equipped with knowledge and gear, the DIY approach can be rewarding. But if you’re aiming for perfection, a professional mechanic is your best bet for maximizing component life and drivetrain efficiency.
For most road cyclists who invest in performance, letting a skilled technician handle installation—especially the first time—often pays off in fewer problems and better peace of mind.