The Most Common SM-BB5700 Problems and How to Solve Them

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The Shimano SM-BB5700 [paid link] Hollowtech II bottom bracket is a widely used external threaded bearing system for road bikes, known for its durability and compatibility with Hollowtech II cranksets. Despite its solid performance, the SM-BB5700 [paid link] is not immune to wear or improper installation, which can lead to issues that compromise your drivetrain efficiency and comfort.

In this detailed guide, we’ll walk through the most common SM-BB5700 problems, how to identify them, and step-by-step instructions for resolving them effectively.

Bearing Creaking or Clicking Under Load

One of the most frequently reported issues with the SM-BB5700 is creaking or clicking noises when pedaling under load. This typically indicates one of three issues: contamination, improper torque during installation, or frame interface irregularities.

Causes and Solutions:

  • Improper Installation Torque: If the bottom bracket cups are under- or over-torqued, they may shift subtly during pedaling. Use a torque wrench [paid link] to ensure that each cup is tightened to Shimano’s recommended torque specification of 35–50 Nm.
  • Contaminants in the Threaded Shell: Dirt or corrosion inside the bottom bracket shell can cause micro-movements. Clean the threads thoroughly and apply anti-seize compound before reinstalling the cups.
  • Frame Shell Irregularities: Ovalized or improperly faced shells can cause misalignment. A professional facing tool should be used to correct this if suspected.

Premature Bearing Wear or Rough Rotation

SM-BB5700 bearings should spin freely with light resistance. If you feel grinding or notice a stiff rotation, it likely points to contamination or lack of lubrication.

Root Causes:

  • Water Ingress: Despite seals, extended exposure to water (especially through pressure washing or wet rides) can compromise the bearing races.
  • Lack of Grease: Over time, the grease within the bearings depletes, especially in humid or high-mileage conditions.

Fix:

  • Inspect and replace the bottom bracket if rotation is not smooth. The SM-BB5700 is not serviceable, so bearing replacement means swapping the entire unit.
  • Ensure all seals and spacers are in place to prevent future water ingress.

Bottom Bracket Loosening Over Time

If the bottom bracket feels loose or exhibits play, this is a sign of either cup loosening or spacer misconfiguration.

Primary Causes:

  • Lack of Threadlocker: During installation, threadlocker or anti-seize compound must be used to prevent the cups from backing out.
  • Incorrect Spacer Setup: For different bottom bracket shell widths (68mm or 70mm), Shimano specifies exact spacer combinations. An incorrect stack can lead to poor clamping force.

Resolution:

  • Disassemble, clean, and reinstall the SM-BB5700 with appropriate spacers and compound.
  • Use a torque wrench [paid link] to achieve correct tightening.

Crank Arm Misalignment or Chainline Issues

Another issue that users sometimes report is difficulty aligning the crank arms, or a chainline that causes shifting problems.

Underlying Problems:

  • Wrong Spacer Configuration: An incorrect number or placement of spacers can offset the crankset laterally, disrupting chainline.
  • Non-Standard Frames: Some road frames, especially older or boutique models, may not have shell widths perfectly suited for Shimano’s default setup.

How to Fix:

  • Reference Shimano’s technical documentation for the precise spacer arrangement based on your shell width.
  • Measure chainline and adjust with spacers if needed to bring it within Shimano’s recommended spec of 43.5mm for road applications.

Noise from Crank-Spindle Interface

Even if the bottom bracket is properly installed, noise can still originate from the spindle interface where the crankset mates with the SM-BB5700 bearings.

Causes:

  • Dry Interface: If the spindle was installed dry, it can creak against the bearing’s inner race.
  • Worn Crank Spindle: After extensive use, the spindle itself may wear unevenly, causing poor contact.

Solution:

  • Remove the crankset, inspect for wear or scoring on the spindle.
  • Lightly grease the spindle before reinstalling to reduce friction.
  • If scoring is visible, consider replacing the crankset to maintain optimal fit and performance.

Rust Staining on Cups or Threads

Rust or discoloration on the bearing cups or frame threads indicates moisture exposure and poor sealing.

Potential Problems:

  • Incorrect Installation Without Grease: Dry installation allows moisture penetration.
  • Worn Seals: Seals on the SM-BB5700 can degrade over time.

Remedy:

  • Remove the bottom bracket, clean thoroughly, and apply fresh anti-seize compound.
  • If rust is severe or cups are corroded, replace the SM-BB5700.

Poor Shifting Performance Linked to BB Shell

While shifting performance is generally attributed to derailleurs, bottom bracket issues can indirectly cause poor gear transitions.

Explanation:

  • Chainline Variance: Misaligned cranks can shift the front chainrings off-center relative to the front derailleur.
  • Bearing Drag: High resistance in the bottom bracket can affect pedaling rhythm, impacting front shifting under load.

Fix:

  • Ensure crankarms are centered and the bearing rotates freely.
  • Reassess spacer setup and cup tightness.

Overheating in Long Climbs

Although rare, SM-BB5700 bearings can heat up during prolonged climbs, particularly if the bearing preload is excessive.

What Happens:

  • Over-tightening the preload cap can crush bearings, increasing drag and temperature.

Correction:

  • Always use Shimano’s recommended preload procedure using the plastic preload cap, tightened just until resistance is felt, then secured with the pinch bolts on the non-drive crank arm.

Frequently Asked Questions (FAQs)

1. Can I service the SM-BB5700 bearings instead of replacing the unit?
No. The SM-BB5700 is a sealed cartridge bearing bottom bracket. If bearings are rough, replace the entire unit.

2. What tools do I need to replace an SM-BB5700?
A Hollowtech II-compatible bottom bracket tool [paid link] and a torque wrench rated up to 50 Nm are required.

3. Why does my new SM-BB5700 creak immediately after installation?
Likely causes include insufficient grease, dry frame threads, or improper torque. Disassemble and re-install using anti-seize compound.

4. How often should I replace the SM-BB5700?
For road use, replacement is recommended every 3,000–5,000 miles depending on ride conditions and maintenance.

5. Is the SM-BB5700 compatible with all Shimano road cranksets?
It’s compatible with Hollowtech II road cranksets. Always check crank model specifications for compatibility.

6. Can I use spacers from other bottom brackets with the SM-BB5700?
Use only Shimano-provided spacers to ensure proper fit and avoid misalignment.

By identifying and addressing these common issues with the SM-BB5700, you can ensure smoother rides, better drivetrain efficiency, and fewer unexpected mechanical problems. Whether you’re a DIY mechanic or tuning up your bike before a big ride, attention to detail in bottom bracket setup goes a long way.