ACB518K Bicycle Headset Bearing 40x51.8x8mm 36°/45° Replace
ACB518K Bicycle Headset Bearing 40x51.8x8mm 36°/45° Replace
ACB518K Bicycle Headset Bearing – 40×51.8×8mm | 36°/45° Contact Angle
Upgrade your bike's steering system with this high-quality ACB518K headset bearing. Engineered from premium bearing steel, this precision-ground angular contact bearing delivers smooth, consistent steering performance for road, mountain, and hybrid bicycles. Compatible with a wide range of headset systems, it's an ideal replacement part for riders who demand reliable handling and long-lasting durability.
Key Specifications
- Model: ACB518K
- Dimensions: 40 × 51.8 × 8 mm
- Contact Angles: 36° / 45°
- Material: High-grade bearing steel
- Package Quantity: 1 piece
- Compatible Systems: MH-P28K, K518KH8, MR127, MR110, TH-073
- Made in: Mainland China
Why Choose This Headset Bearing?
- ✅ Precision Engineering: Angular contact design ensures minimal play and maximum directional control during every ride.
- ✅ Durable Bearing Steel: Resists wear and fatigue through thousands of steering cycles for extended service life.
- ✅ Wide Compatibility: Drop-in replacement for multiple popular headset standards — no custom fitting required.
- ✅ Easy Installation: Standard dimensions make swapping out worn bearings quick and straightforward with common workshop tools.
- ✅ Smooth Action: Precision ball races reduce friction for effortless, responsive steering feel.
Perfect For
Whether you're maintaining a road bike, setting up a mountain bike headset, or restoring a commuter bicycle, this ACB518K bearing is the dependable replacement part you need. Suitable for both DIY home mechanics and professional bike workshop technicians.
Note: Please allow 2–3% dimensional tolerance due to manual measurement. Actual product color may vary slightly from images due to monitor display differences.
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Frequently Asked Questions
Q: What bicycle headset systems is the ACB518K bearing compatible with?
A: The ACB518K headset bearing is compatible with MH-P28K, K518KH8, MR127, MR110, and TH-073 headset systems. Its standard 40×51.8×8mm dimensions also make it a strong match for other headsets sharing the same bore and contact angle specifications — always verify your headset's dimensions before ordering.
Q: What is the difference between the 36° and 45° contact angles?
A: Angular contact bearings come in different contact angles that affect how load is distributed. A 36° contact angle handles a balance of radial and axial loads, while a 45° angle offers greater axial (thrust) load capacity. Check your headset manufacturer's specifications to confirm which angle is required for your system.
Q: Is this bearing suitable for both road and mountain bikes?
A: Yes — provided your headset matches the ACB518K's 40×51.8×8mm dimensions and 36°/45° contact angle, this bearing is suitable for road, mountain, hybrid, and other bicycle types. Always cross-reference with your headset model number (such as MH-P28K or TH-073) to ensure a correct fit.
Q: How do I install the ACB518K headset bearing?
A: Installation typically involves removing the fork, pressing out the old bearing using a headset press tool or bearing driver, cleaning the headtube cup, and pressing the new bearing evenly into place. It is recommended to use proper headset press tools to avoid damaging the bearing races. Consult your bike's service manual or a qualified bicycle mechanic if unsure.
Production & Packaging Notice
To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.