I just want to say a massive thanks to Welink team. We had a really tight deadline for a prototype requiring specific deep groove ball bearings, and they were brilliant. They understood our needs immediately, rushed samples over, and followed up to ensure perfect performance. It's that attentive service that sets them apart. They've been a great help, and we're already looking forward to our next project together. Highly recommended.
Key Takeaways:
* Load Capacity: Full ball designs increase ball count by 30%–50%, boosting radial load capacity by 35%–45%.
* Best For: Low-speed oscillation, high impact, and space-constrained applications like MTB suspension pivots.
* Technical Specs: Features deepened raceways, C2 small clearance, and high-performance VRS/LLU seals.
* Speed Limit: Not recommended for continuous high-speed rotation (typically <1000 RPM).
I. The "Invisible Framework" — Why Remove the Cage?
In standard deep groove ball bearings, the cage separates steel balls to prevent friction. However, in heavy-duty thin-section bearings (like the 68/69 series), the cage occupies valuable internal space.
By removing the cage, we create a Full Ball (MAX) Bearing. Think of it like a bus: removing the seats (the cage) allows more passengers (steel balls) to stand inside, significantly increasing the "carrying capacity."
II. Why 68/69 Series "Full Ball" is the Choice for Engineers?
The 68 and 69 series are ultra-thin walled bearings designed for compact spaces. When standard caged versions aren't enough, the full ball design provides a critical performance upgrade:
▪ Massive Static Load Rating (C0): With 30%–50% more steel balls, the load is distributed across more contact points, reducing the pressure on each individual ball.
▪ Impact Resistance: In applications like mountain bike pivots, the cage is often the "weak link" that fractures under sudden shocks. A cage-free design eliminates this failure point entirely.
▪ Enhanced Stability: These bearings typically feature deepened raceways and C2 small clearance to reduce internal shaking and improve axial stability.
| Comparison Metric | Standard Caged Bearing | Full Ball (MAX) Bearing |
| Radial Load Capacity | Baseline | +35% to 45% Higher |
| Impact Resistance | Moderate (Cage may break) | High (No cage to fail) |
| Speed Limit | High (e.g., 20,000+ RPM) | Low (Recommended <1000 RPM) |
| Typical Clearance | CN (Normal) | C2 (Tight/Stable) |
III. Typical Applications: From Bicycles to Industry
The 68/69 and thickened 638 series full ball bearings are ideal for oscillating conditions where high speed isn't required, but durability is non-negotiable.
▪ Cycling: Suspension pivots and rear swing arms (6801-VRS, 6902-LLU).
▪ Construction: Small excavator connecting rods and skid steer loader swing shafts.
▪ Industrial: Flip tooling, connecting rod pivots, and agricultural harvester pivots.
IV. Selection & Installation Pro-Tips
① Check Dimensions: Full ball bearings share the exact same external dimensions as standard models, making them a direct "drop-in" upgrade.
② Seal Choice: For dusty or muddy environments (like MTB trails), specify VRS or LLU double-lip labyrinth seals for maximum protection.
③ Lubrication: We recommend a slightly higher grease fill (70%–80%) to ensure a consistent oil film between the contacting balls.
④ Precision Press-Fit: Due to the tighter C2 clearance, use a professional press-fitting tool to avoid misalignment or jamming.
V. Quick FAQ
Q: Are they more expensive?
A: Usually 10%–25% more due to the labor-intensive manual assembly of the extra balls. However, this is highly cost-effective for a 40% gain in load capacity.
Q: Can I use them in an electric motor?
A: No. The friction between steel balls without a cage generates heat at high speeds. They are strictly for low-speed or oscillating applications.
Need a Technical Drawing or Bulk Quote?
If your equipment needs to "undertake heavier work" in a limited space, Welink Bearing provides premium 68/69/638 VRS-MAX series with optimized internal geometry.
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