Information
The IS41│IS52 headset is designed to fit frames with integrated 41mm/52mm head tubes and works with tapered and straight fork steerers. The “IS” stands for “Integrated” as the bearing sits directly inside the frame’s head tube without a cup. The “41/52” stands for the top/bottom inside diameter of the frame’s head tube.
Note: As of 9/14/23, headsets will no longer include Star Nuts due to the Earth’s star nut overpopulation crisis. If you need one, they are available separately here.
Features
- U.S. sourced 6061-T6 aluminum
- Machine engraved White Industries logos
- Easily replaceable Enduro bearings
- “Split” crown race for tool-free installation and removal
- Really sweet matching headset spacers available separately
- Can accommodate 3 types of fork steerers:
- “Straight” 1-1/8″ with a 30mm crown race
- “Tapered 1-¼” with a 33mm crown race seat
- “Tapered 1-1/2” with a 40mm crown race seat
Specs
- SHIS specification
- Upper: IS41/28.6
- Lower: IS52/33 or IS5240
- Stack height
- Upper: 8mm
- Lower: 1mm
- 45 degree outer contact angle
- SHIS definitions on the Park Tools website: here
- Frame/Fork specs:
|
Frame upper head tube inside diameter |
41.10mm to 41.2mm with a 45 degree contact angle |
|
Frame lower head tube inside diameter |
52.05mm to 52.15mm with a 45 degree contact angle |
|
Fork steerer diameter top section |
28.45mm to 28.6mm |
|
Crown race seat diameter for “straight 1-⅛” |
30.015mm to 30.075mm |
|
Crown race seat diameter for “tapered 1-1/4” |
33.03mm to 33.09mm |
|
Crown race seat diameter for “tapered 1-1/2” |
39.79mm to 39.85mm |
Bearings
|
Headset Model |
Upper Bearing (inner/outer angle) | Lower Bearing
(inner/outer angle) |
Lower Fork Race Compatibility |
|
IS41│IS52 |
ACB3645SS 36/45 | ACB6808CCSS 36/45 |
1-⅛” (30mm) 1-¼” (33mm) 1-½” (40mm) |
