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  1. #1
    electrostark
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    converting a JIS fork to ISO

    i have a fork that is set up for JIS (27.0 crown race), is it possible to convert it to ISO (26.4) And if so, will the treads on the fork still be compatible.

    thanks.
    Last edited by electrostark; 06-09-08 at 08:27 AM.

  2. #2
    Senior Member cizzlak's Avatar
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    the crown race is too big to seat on the fork as is. a crown race is a pretty sensitive piece of metal, for as small as it is. you would need to add material to it in order for it to snug up, and that would not be very practical or safe. and the threading is not compatible. i dont believe you would be able to successfully retap it due to this fact. look for a new headset or fork, whichever you can find easier.

  3. #3
    Senior Member bellweatherman's Avatar
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    Quote Originally Posted by cizzlak View Post
    the crown race is too big to seat on the fork as is. a crown race is a pretty sensitive piece of metal, for as small as it is. you would need to add material to it in order for it to snug up, and that would not be very practical or safe. and the threading is not compatible. i dont believe you would be able to successfully retap it due to this fact. look for a new headset or fork, whichever you can find easier.


    I think what he is asking is whether or not it is ok to cut the fork steerer/crown down from a 27.0mm (JIS) to a 26.4mm (ISO), so that he can later install an ISO headset and crown race (ie baseplate). So basically, he wants to make his JIS fork into an ISO fork by removing metal, not adding metal.

    The threads at the top of the steerer have nothing to do with JIS or ISO standards. JIS and ISO only refer to the thickness where the crown race (ie base plate) sits.
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  4. #4
    Senior Member cizzlak's Avatar
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    you're right.

  5. #5
    Senior Member Iowegian's Avatar
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    And of course the answer is 'yes, it's possible'. Any decent bike shop should be able to do this for you.

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