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Bike component fitment: bottom bracket, headset, seatpost, axle

A Argon 18 Krypton uses a IS42 integrated upper headset (integrated, 42 mm). The dimensions, how to confirm it on your frame, and how it compares to the neighbouring standards.

Updated 05 September 2026.

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What headset does a Argon 18 Krypton use?

The headset fitment standard on a Argon 18 Krypton, and how to pick the right part.

DROPS IN
A Argon 18 Krypton uses a IS42 integrated upper headset (integrated, 42 mm).
This frame's fitment
FrameArgon 18 Krypton
Headset standardIS42 (integrated, 42 mm)
Cup / bearing outside diameter41.8 to 42.0 mm bearing outside diameter
Steerer diameter28.6 mm (1 1/8 in)

The Argon 18 Krypton uses a IS42 integrated upper headset (integrated, 42 mm), a 27.2 mm class seatpost, a 12x100 mm front thru-axle at the front (12 mm x 100 mm, front) and a braze-on front derailleur.

The 27.2 mm figure is the mainstream disc-road interface; many of these frames ship a proprietary aero-shaped post, so confirm the exact part. The bottom bracket is covered on its own page.

The part to buy
Shop IS42 for your Argon 18 Krypton on AmazonaffiliateFind IS42 for your Argon 18 Krypton on eBayaffiliate
Related fitment pages
IS42integrated, 42 mmBottom bracket for Argon 18 Kryptonsame frame, BB shellSeatpost diameter on a Argon 18 Kryptonsame frameIS42 on a Trek Emonda SLR (2024 on)same standard, another frame

SOURCES: Park Tool, Standardized Headset Identification System (SHIS) · BikeGremlin, Bicycle headset bearing standards (SHIS) · BikeRadar, Road bike axle standards: the complete guide

Questions and answers

What headset does a Argon 18 Krypton use?

A Argon 18 Krypton uses a IS42 integrated upper headset (integrated, 42 mm).