The listing says 1 1/8",that's what your stock fork is. Note,the steerer tube doesn't slide directly into the frame's headtube,it threads through the headset.
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C'dale BBU('05 and '09)/Super Six/Hooligan8and 3,Kona Dew Deluxe,Novara Buzz/Safari,Surly Big Dummy,Marin Pt Reyes,Giant Defy 1,Schwinn DBX SuperSport,Brompton S6L/S2E-X/M6L-X/S12 T Line
