IS42 headset standard (integrated, 42 mm)
What a IS42 headset measures under the SHIS standard, and how to tell it apart from lookalikes.
Published dimensions
| SHIS designation | IS42 (integrated (IS)) |
|---|---|
| Cup / bearing outside diameter | 41.8 to 42.0 mm bearing outside diameter |
| Steerer diameter | 28.6 mm (1 1/8 in) |
| Crown race | 30.0 mm crown race, or machined into the fork |
Used on: the Campagnolo Hiddenset 1 1/8 in integrated upper on many modern road frames.
IS42 is the Campagnolo-derived integrated upper: a 41.8 to 42.0 mm bearing sits directly in the head tube for a 28.6 mm steerer. It is close to IS41 in size but uses a 45x45 degree bearing; confirm the exact bearing part before buying.
Frames and related headsets
Headset on a Trek Emonda SLR (2024 on)integrated, 42 mmHeadset on a Specialized Tarmac SL8 (2024 on)integrated, 42 mmHeadset on a Canyon Ultimate CF (2020 on)integrated, 42 mmEC34external cup, 34 mmEC44external cup, 44 mmBSA bottom bracket shellthe frame's other threaded interface
SOURCES: Park Tool, Standardized Headset Identification System (SHIS) · BikeGremlin, Bicycle headset bearing standards (SHIS)