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SKU: ec34ec37
Clear Options


The EC34│EC37 headset is designed to fit frames with tapered head tubes and can accommodate straight 1-1/8″ and tapered 1-1/4″ (33mm) fork steerers with the appropriate crown race.  The “EC” stands for “External Cup” meaning the section of the cup that houses the bearing sits outside of the frame’s head tube and the “34”/”37” (top/bottom) stands for the 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. 



  • 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



    • SHIS specification
      • Upper: EC34/28.6
      • Lower: EC3733
    • Stack height
      • Upper: 15mm
      • Lower: 12mm
    • SHIS definitions on the Park Tools website: here
    • Frame/Fork specs:

    Frame upper head tube inside diameter

    33.9mm to 33.95mm

    Frame lower head tube inside diameter

    36.8mm to 36.95mm

    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



    Headset Model

    Upper Bearing (inner/outer angle) Lower Bearing 

    (inner/outer angle)

    Lower Fork Race Compatibility


    ACB3645SS  (36/45) ACB45/45125LSS (45/45)

     1-¼” (33mm)


Additional information

Weight N/A
Dimensions N/A
Head Tube

Top Steerer

Bottom Steerer / Crown Race