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

A Trek Crockett (2020 on) 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 Trek Crockett (2020 on) use?

The headset fitment standard on a Trek Crockett (2020 on), and how to pick the right part.

DROPS IN
A Trek Crockett (2020 on) uses a IS42 integrated upper headset (integrated, 42 mm).
This frame's fitment
FrameTrek Crockett (2020 on)
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 Trek Crockett (2020 on) 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.

Gravel builds are often 1x, so the front-derailleur mount can go unused. The 27.2 mm post is the class default; confirm the exact part before buying. The bottom bracket is covered on its own page.

The part to buy
Shop IS42 for your Trek Crockett (2020 on) on AmazonaffiliateFind IS42 for your Trek Crockett (2020 on) on eBayaffiliate
Related fitment pages
IS42integrated, 42 mmBottom bracket for Trek Crockett (2020 on)same frame, BB shellSeatpost diameter on a Trek Crockett (2020 on)same 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 Trek Crockett (2020 on) use?

A Trek Crockett (2020 on) uses a IS42 integrated upper headset (integrated, 42 mm).