FSA IS-2 1-1/8"
FSA

FSA IS-2 1-1/8"

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The FSA IS-2 is a lightweight, integrated 1-1/8" headset featuring ACB sealed bearings, 16.8mm stack height and precision aluminum construction — ideal for road bikes with IS41 cups.

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Product Details

Overview & Technology

FSA's IS-2 is a purpose-built integrated headset for 1-1/8" steerers, engineered to deliver crisp steering and long-lasting durability without adding unnecessary weight. The body is machined from lightweight aluminum and fitted with blue-sealed ACB bearings (36°/45°) top and bottom for smooth, low-friction performance. The IS-2 uses an IS41/28.6 upper and IS41/30 lower standard, with a slim 16.8mm stack height that keeps your cockpit tidy and the front end responsive. Sealed ACB bearings protect against grit and moisture for consistent feel mile after mile.

Key Features & Benefits

Precision bearings: Matched 36°/45° ACB sealed bearings (blue) on both upper and lower races reduce play and increase longevity compared to loose or unsealed bearing sets. Expect smooth rotation and improved steering feedback. • Aluminum construction keeps weight down — headset weight is just 65g. • Low 16.8mm stack height preserves handlebar-to-stem fit and allows more spacer or stem options. • Compatible with standard IS41 frame bores and 1-1/8" steerer tubes for straightforward upgrades or replacements.

Fit, Compatibility & Installation Notes

This headset is designed for frames with a headtube outer/inner diameter of 45mm/41.2mm and conforms to SHIS IS41/28.6 (upper) and IS41/30 (lower). The crown race diameter is 30mm, and the cups press into a 41mm lower cup seat. It’s supplied as a complete headset for 1-1/8" straight steerers. Installation requires a proper headset press to seat the cups squarely and a 30mm crown race-compatible tool. Because the design uses sealed ACB bearings, use a thin film of waterproof bearing grease on the cups and crown race during installation to maximize life and prevent creak.

Who This Headset Is For

The FSA IS-2 is aimed at road and light-gravel riders running a straight 1-1/8" steerer and IS41-integrated frames who want a minimal, reliable headset with excellent sealing and low weight. It’s a strong choice for racers, commuters or anyone refreshing the front end with a clean, lightweight unit. If you have a tapered steerer, need headset bearings for mixed steerers, or require an external cup system, choose a headset matched to those standards instead. The IS-2 shines where integration, low stack and precision are top priorities.

Key Features

  • ✓ Ultra-light aluminum construction — total headset weight 65 grams
  • ✓ Sealed 36°/45° ACB blue bearings upper and lower for smooth life
  • ✓ Low 16.8mm stack height keeps cockpit compact and adjustable
  • ✓ SHIS compatibility: IS41/28.6 upper and IS41/30 lower
  • ✓ Designed for 1-1/8" straight steerers; crown race Ø 30mm
  • ✓ Ideal for road frames with 45mm outer / 41.2mm inner headtube
  • ✓ Packed complete — upper & lower bearings and cups included
  • ✓ Blue-sealed bearings for improved water and dirt protection

Specifications

Bearing Grade ACB Sealed
Crown Race Diameter 30mm
Lower Cup 41mm
Headset Type Integrated
Upper Cup 41mm
Headset Weight 65g
Misc 36°/45° ACB (blue seal)
Material Aluminum
Primary Color Silver
S.H.I.S. IS41/28.6 | IS41/30
Steerer Tube 1-1/8''
Stack Height 16.8
Headset Position Complete
SHIS Upper IS41/28.6
SHIS Lower IS41/30

Product Identifiers

Vendor Item # 121-0325N
UPC 400310002723

Frequently Asked Questions

Will this headset fit my bike frame?

The IS-2 fits integrated frames using the IS41 standard: upper SHIS IS41/28.6 and lower SHIS IS41/30. Confirm your headtube OD/ID (45mm/41.2mm) and a straight 1-1/8" steerer. It will not fit tapered steerers without an adapter.

What tools are required to install the IS-2 headset?

You should use a headset press to install the cups squarely and a crown race installer for the 30mm crown race. A torque wrench for stem/expander bolts and a thin layer of waterproof grease for the cups/bearings will ensure correct installation and quiet operation.

How durable are the bearings and how often should I service them?

The IS-2 uses ACB sealed bearings which offer excellent protection against dirt and water. Service interval depends on conditions — inspect annually for play or roughness, and in wet or muddy conditions check/refresh grease every 6–12 months. Replace bearings if you detect grit or uneven rotation.

Can I use this headset with a carbon steerer?

Yes — the headset is compatible with 1-1/8" carbon or aluminum steerers provided you follow carbon torque specifications for stem clamps and use carbon assembly paste where recommended. Ensure your stem and expander hardware are rated for carbon steerers.

What is the difference between the blue ACB bearings and standard bearings?

ACB (Angular Contact Bearings) are preloaded and matched angles (36°/45°) control axial and radial loads more effectively, improving steering precision and reducing play. The blue seal indicates FSA's sealed variant for better contamination protection compared with unsealed or lower-grade bearings.

Does the headset come with a crown race?

The IS-2 is a complete headset package and includes the necessary cups and bearings. Verify that a crown race is included in the box; if not, FSA crown races for 30mm steerers are the correct match (30mm crown race diameter).

Buying Guide

When choosing an integrated headset, confirm the SHIS standard for your frame (IS41 upper / IS41 lower for this model) and your steerer type (straight 1-1/8"). Decide whether low stack height or maximum adjustability is the priority — the FSA IS-2's 16.8mm stack keeps the cockpit low and tidy. Pay attention to bearing type and sealing: ACB sealed bearings like the IS-2's blue seals offer better load handling and protection for long-term smoothness. Finally, plan to install with the correct tools (headset press and crown race tool) to avoid damaging the cups or bearings.

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