Information
The ZS44│ZS56 headset is designed to fit frames with tapered 44mm/56mm head tubes and works with tapered 1-1/2” fork steerers. The “ZS” stands for “Zero Stack” as the section of the cup that houses the bearing sits inside of the frame’s head tube. The “44/56” stands for the top/bottom diameter of the “skirt” that presses into the frame.
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 “tapered 1-1/2” forks with a 40mm crown race seat
Specs
- SHIS specification
- Upper: ZS44/28.6
- Lower: ZS56/40
- Stack height
- Upper: 8mm
- Lower: 4mm
- SHIS definitions on the Park Tools website: here
- Frame/Fork specs:
|
Frame upper head tube inside diameter |
43.95mm to 44mm |
|
Frame lower head tube inside diameter |
55.9mm to 55.95mm |
|
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 1-¼” |
33.03mm to 30.09mm |
|
Crown race seat diameter for “tapered 1-½” |
39.79mm to 39.85mm |
Bearings
|
Headset Model |
Upper Bearing (inner/outer angle) | Lower Bearing
(inner/outer angle) |
Lower Fork Race Compatibility |
|
ZS44│ZS56 |
ACB3645SS 36/45 | ACB6808CCSS 36/45 | 1-⅛” (30mm)
1-¼” (33mm) 1-½” (40mm) |
