FSA Micro ACB
FSA

FSA Micro ACB

In Stock

Replacement sealed cartridge headset bearing from FSA — 1-1/8" 36°x36°. Durable, low-friction unit (part 160-6500B) that restores smooth steering and reduces maintenance.

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Product Details

Overview & Technology

FSA Micro ACB is a sealed cartridge headset bearing designed to bring back precise, smooth steering to frames that use a 1-1/8" headset with 36° x 36° contact angles. The cartridge design houses precision steel balls and hardened races inside a single, serviceable unit so installation is fast and alignment is consistent. The bearing features a low-friction rubber seal and hardened chromium-steel components to resist wear and corrosion in real-world riding conditions. Because the unit is sealed, it keeps contaminants out and grease in, delivering long life and reliable performance whether you ride daily or store your bike between seasons.

Key Features & Construction

Precision materials and thoughtful engineering make the Micro ACB a dependable choice for headset service. The cartridge uses heat-treated chromium-steel races and precision chrome steel balls for consistent rolling characteristics and longevity under load. A bonded rubber seal protects the internal bearings from water, grit and road debris. • Sealed cartridge design for low maintenance and fast replacement • 36° x 36° contact geometry — optimized for many 1-1/8" headsets • Durable chromium-steel races and precision balls for smooth steering • Black rubber seal to keep contaminants out and grease in

Fit, Dimensions & Compatibility

The Micro ACB is specified for 1-1/8" (1.125") headset applications with a 36° x 36° bearing angle — FSA part number 160-6500B (vendor MR033). Check your headset cup or frame documentation to confirm a 36° contact angle and ID/OD dimensions before ordering. This single cartridge is sold individually as a replacement bearing (Product No. 150314). Shipping dimensions are compact (3" x 2" x 0.2") and weight is minimal (~0.01 lb), making it ideal for keeping a spare in your toolbox. If your headset uses two bearings (upper and lower), plan to replace both sides for even wear and optimal steering performance.

Who This Bearing Is For

This Micro ACB is aimed at road and gravel riders, home mechanics, and bike shops looking for an OEM-spec replacement bearing to restore precise steering. It's perfect when the original bearing has play, roughness, or contamination but the cups and fork steer tube are still true. If you value low maintenance, reliable performance and quick installation, the FSA Micro ACB is an affordable, high-impact service item. It's also a practical spare for racers and commuters who need to minimize downtime between rides.

Key Features

  • ✓ Sealed cartridge bearing for low maintenance and long life
  • ✓ Designed for 1-1/8" headsets with 36° x 36° contact angles
  • ✓ Hardened chromium-steel races and precision chrome steel balls
  • ✓ Black rubber sealing to keep out water, grit and dust
  • ✓ OEM FSA part 160-6500B — vendor MR033, product 150314
  • ✓ Sold individually — ideal for single-side replacement or spares
  • ✓ Compact, lightweight unit for quick, straightforward installation

Specifications

Number 160-6500B
Bearing Dimensions 1-1/18'' 36x36

Product Identifiers

Vendor Item # 160-6500B
UPC 400310039248

Frequently Asked Questions

Will this bearing fit my bike?

The Micro ACB fits headsets that use a 1-1/8" (1.125") bearing with 36° x 36° contact angles. Confirm the bearing angle and diameter in your headset or frame documentation before purchasing. If both upper and lower bearings use the same spec, replace them as a matched pair for best results.

How easy is it to install the sealed cartridge?

Installation is straightforward for anyone comfortable with basic headset service: press the cartridge into the cup squarely using a bearing press or appropriate drift, reassemble the stem and top cap, then preload and torque to spec. If you're unsure, a bike shop can install it quickly to ensure alignment.

Do sealed cartridges need regular maintenance?

Sealed cartridge bearings require much less maintenance than loose-ball setups. The rubber seal retains grease and keeps contaminants out, but periodic inspection and cleaning of the headset area is recommended. If the seal is damaged or the bearing feels rough, replace the cartridge.

Can I replace just one bearing instead of both?

You can replace a single worn bearing, but matching wear and preload is easier when both upper and lower bearings are new. Replacing both bearings reduces chances of uneven steering feel and extends the life of the new cartridge.

What materials are used in the Micro ACB?

The Micro ACB uses heat-treated chromium-steel races and precision chrome steel balls with a bonded rubber seal. This combination balances durability, load capacity, and corrosion resistance for headset applications.

Is this an OEM part for FSA headsets?

Yes — this is an FSA OEM-style replacement: part number 160-6500B (vendor MR033), product number 150314. It matches the dimensional and performance expectations of FSA Micro ACB headset systems.

Buying Guide

When buying headset bearings, match the bearing diameter and contact angle to your frame's headset cups. Sealed cartridge bearings like the FSA Micro ACB simplify replacement because the entire precision unit is swapped rather than servicing individual balls or races. Choose OEM or OEM-equivalent parts if you want guaranteed fitment and original tolerances. Keep a spare cartridge in your tool kit if you ride frequently or race — a simple on-the-road swap can save a day of downtime.

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