The Shimano SM-BB6700 [paid link] is a Hollowtech II external-threaded bottom bracket, designed specifically for road cyclists who demand reliability, stiffness, and longevity. Meanwhile, the SM-BB71-41B is a press-fit bottom bracket option for frames designed around the BB86/BB92 standard. Although both models are part of Shimano’s road bike ecosystem and support Hollowtech II cranksets, they serve very different frame types and riding needs. In this detailed comparison, we’ll break down the crucial differences in construction, installation, maintenance, compatibility, and performance to help you determine which model suits your bike setup best.
Bottom Bracket Type and Frame Compatibility
The most critical difference between the SM-BB6700 [paid link] and SM-BB71-41B lies in their frame compatibility.
- SM-BB6700 [paid link] is an external threaded bottom bracket, specifically designed for English-threaded (BSA) bottom bracket shells measuring 68mm or 70mm in width.
- SM-BB71-41B, on the other hand, is a press-fit model compatible with BB86/BB92 shell standards, commonly found in modern carbon fiber road frames.
The choice between these two models often comes down to what your frame supports. Threaded bottom brackets like the SM-BB6700 are known for easier maintenance and less creaking, while press-fit models such as the SM-BB71-41B reduce weight and offer a more integrated look but are often more sensitive to frame tolerance inconsistencies.
Installation Process
Installation procedures between these two models vary significantly due to their respective designs.
- SM-BB6700 installation involves:
- Threading the bearing cups into the frame’s shell using a Hollowtech II bottom bracket tool [paid link].
- Applying anti-seize or threadlocker to reduce the chance of noise or galvanic corrosion.
- SM-BB71-41B requires:
- Pressing the bearing cups directly into the frame using a bearing press [paid link] tool.
- Ensuring the frame’s shell faces are clean and within tolerance to avoid misalignment.
Mechanics often prefer the SM-BB6700 for its simplicity and reusability during multiple removals and installations. The SM-BB71-41B is lighter and more compact, but improper installation can lead to creaking or premature wear if the frame tolerances are not precise.
Bearing Quality and Sealing
Both bottom brackets use Shimano’s high-quality steel bearings and effective sealing systems, but there are subtle differences in design that affect real-world performance.
- SM-BB6700 offers superior sealing with its cup-based design that positions the bearings outside the shell, helping them stay cooler and more accessible for maintenance.
- SM-BB71-41B positions the bearings inside the frame shell, which limits external exposure, but also makes it harder to clean or replace bearings without professional tools.
If you ride in wet or dirty conditions, the SM-BB6700’s more accessible bearings and robust outer seals may prove more durable over time.
Durability and Service Life
Durability is a priority for road cyclists who log thousands of miles. Here’s how the two compare:
- SM-BB6700 has a longer service interval due to its external bearing positioning and better access for cleaning and greasing.
- SM-BB71-41B, being press-fit, tends to wear faster in the presence of poor frame tolerances or contamination entering the shell through internal cable routing or water ingress.
Over time, threaded bottom brackets tend to develop fewer noise issues and require fewer frame-dependent service interventions than press-fit models.
Performance on the Road
When installed correctly, both bottom brackets deliver smooth, efficient pedaling. However, each model offers a slightly different road feel:
- SM-BB6700 provides a slightly stiffer interface because the bearings are mounted externally, creating a wider stance. This can lead to improved power transfer, especially under sprinting or climbing loads.
- SM-BB71-41B offers a lighter overall setup with fewer external components. The narrower stance may suit riders who prefer a more compact Q-factor or are chasing weight savings.
Your riding style and performance goals will help determine which option better suits your needs.
Maintenance and Replacement
- SM-BB6700 is highly serviceable. You can clean, regrease, or replace the cups easily using common bottom bracket tools.
- SM-BB71-41B often requires a bearing press [paid link] and specialized extractor tools, which makes DIY maintenance more complicated and less frequent.
For cyclists who prefer hands-on maintenance or regular servicing, the SM-BB6700 is a more practical option.
Price and Value
While pricing can vary slightly by retailer and region, both models are priced similarly in Shimano’s mid-range component line. However, value depends largely on what your bike frame can accommodate:
- If your frame has a BSA threaded shell, the SM-BB6700 offers unmatched longevity and ease of maintenance for its price.
- If you’re on a BB86/BB92 frame, the SM-BB71-41B is your only compatible option in Shimano’s lineup unless you use an adapter.
Noise and Fitment Issues
Press-fit systems like the SM-BB71-41B have developed a reputation for creaking due to imperfect tolerances in carbon frames. The SM-BB6700, being threaded, generally eliminates this issue entirely. For riders who are sensitive to drivetrain noise or want a quiet, fuss-free ride, the SM-BB6700 has a clear advantage.
Summary Comparison Table
| Feature | SM-BB6700 (Threaded) | SM-BB71-41B (Press-Fit) |
|---|---|---|
| Frame Compatibility | BSA Threaded Shell (68/70mm) | BB86/BB92 Press-Fit Shell |
| Installation Tool | Hollowtech II Wrench | Bearing Press [paid link] Tool |
| Ease of Maintenance | High | Moderate to Low |
| Durability in Wet Riding | Excellent | Moderate |
| Bearing Position | External | Internal |
| Creak Resistance | Very High | Variable (Frame-dependent) |
| Weight | Slightly Heavier | Lighter |
| Service Interval | Longer | Shorter |
| Ideal For | DIY Mechanics, Long-Term Durability | Lightweight Builds, BB86 Frames |
Conclusion
Both the Shimano SM-BB6700 and SM-BB71-41B are engineered to serve different use cases within the road cycling world. If you’re riding a frame with a threaded shell and value durability, easy maintenance, and long-term reliability, the SM-BB6700 is the superior choice. On the other hand, for riders using a BB86/BB92 press-fit frame, the SM-BB71-41B delivers excellent performance with a lighter and cleaner design—assuming the frame tolerances are up to standard.
When choosing between these two, always start with your frame’s bottom bracket shell type. From there, consider your preferences for maintenance, noise control, and long-term serviceability.