Press-fit bottom bracket (BB) bearings in bicycle frames require a secure hold to resist pedaling forces, torque, and creaking from micro-movement. However, they are a serviceable component designed to be replaced periodically. This demands a retaining compound that offers secure, anti-vibration strength while allowing for future, non-destructive removal.
This is a Medium Strength, Serviceable application.
INCURE WeldLock™ 338 Retaining Compound (Yellow)
The INCURE WeldLock™ 338 Retaining Compound is the ideal functional “Medium Strength” solution. It is designed for assemblies where future disassembly is required, providing enough holding power to eliminate movement and silence creaks without making bearing removal a destructive process.
| Key Feature | Performance for BB Bearings |
| Serviceable Bond (Yellow) | Specifically designed for assemblies requiring removal or repositioning. Locks the bearing securely but allows for easier, non-destructive separation when the bearing wears out. |
| Excellent Vibration Resistance | Provides reliable holding power against continuous pedaling forces and road shock, eliminating the movement that causes creaking. |
| Gap Fill (Up to 0.25mm) | Effectively fills the annular space, compensating for minor frame manufacturing tolerances and ensuring a solid, unified interface. |
| Temperature Resistance (150∘C) | Maintains integrity under standard cycling operational temperatures. |
Application Steps: Installing Press-Fit Bottom Bracket Bearings
For optimal retention and reliable, yet removable, installation of BB bearings, follow these steps:
1. Surface Preparation (The Foundation)
- Clean: Thoroughly clean the frame’s bottom bracket shell bore and the bearing’s outer race. Surfaces must be absolutely free of all grease, oil, and contaminants. Use a cleaner (e.g., isopropyl alcohol or acetone) and wipe dry.
- Activate (If Needed): While usually not required, applying a chemical activator can ensure faster, more consistent curing, particularly in cold environments.
2. Product Application
- Apply: Apply a continuous, thin bead of WeldLock™ 338 around the full circumference of the outer race of the bearing or the internal bore of the bottom bracket shell.
- Ensure Coverage: Ensure the adhesive completely wets the entire mating surface as the bearing is inserted.
3. Assembly and Curing
- Assemble: Immediately use a proper press-fit tool to press the bearing into the BB shell. Ensure the bearing is fully seated and aligned correctly before the compound fixtures.
- Wipe Excess: Remove any excess adhesive visible outside the joint immediately after pressing.
- Cure: Allow the assembly to fixture before handling (typically 10-30 minutes). Allow a full 24 hours for the compound to reach maximum strength before riding the bicycle.