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  1. #1
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    Fitting BMX forks to a dahon?

    Hi all,

    I am trying to electrify my Danon, convert it to electric that is. I have a front hub motor that is for a standard 100 mm hub width and I need to change my narrow forks to ones that fit.

    BMX forks come to mind but they are all un threaded ahead styled steer tubes, unfortunately I have an older model dahon with a quil setup and threaded forks.

    I am pretty sure I can get the standard BMX 1 1/8 steer tube threaded but will my quill still fit? I noticed there is some pretty sever butting in my current steer tube and I am not sure if they bother with ahead setup.

    Has anyone out there tried fitting 100m forks to their dahon?

    Cheers
    Derek
    Last edited by mingonn; 08-19-08 at 08:50 PM.

  2. #2
    jur
    jur is offline
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    You will have to measure some dimensions for anyone to be able to answer.
    My folding bike photo essays www.dekter.net/

  3. #3
    Senior Member
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    Dahon headsets are partially built into the fork, I've just discovered. I can't see any easy way to adapt a standard fork so that it fits, unless there's a headset upgrade where the lower portion isn't integrated into the fork?

  4. #4
    tinmantis
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    I don't know much about Dahon's but...
    are you sure you'll need a 1+1/8th steerer? my 3 vintage folders are all 1"

    Some BMX forks DO come threaded (I just got one) but road stems/road quills do not fit down them. One inch road stems are 22.2mm outside diameter, and BMX !" steerers are 21.1mm inside diameter.
    but
    I had a machine shop ream my BMX steerer up to 22.2mm ID, so I can use road 'stuff' with it...
    but watch your headtube height. BMX forks come with different size steerers, short and long
    hope that vaguely helps!
    regards
    jon

  5. #5
    Senior Member
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    Just get a cheap boys MTB
    rip the forks from it

    But check the handlebar stem is the right diameter.
    Just need to remove the stem and see the number on it

  6. #6
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    I have take some photos showing the current setup. Quill has 25.4mm stamped on it and forks have 20x116 stamped.

    I think there is a bicycle recycle place near me so I might just take the forks and quill down and try my luck.

    The cheap boys 20" mtb sounds promising.

    Cheers
    Derek
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  7. #7
    Senior Member
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    Oh I didnt know the size
    Cheap MTBs will be 22.2mm handlebar stem size.

    So you'd have to look hard to get a threaded fork in 1 1/8" oversize
    As thats the common Aheadset size.

    Looks like the bearing race on the forks is a normal removable one.

  8. #8
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    This is getting harder and harder.

    Went down to the second hand bike shop and it seems that 1 1/8 steer tubes designed for ahead stems are not internally butted so will not accept my dahon quill. Now I am stuck with converting the whole lot over to ahead.

    Fall back plan now is to see if I can get 1 1/8 threaded rigid mtb forks and shorten them. Failing this I will try using a pair or un threaded BMX forks and extend the 1 1/8 steer tube to the height of my handle bars. Will need to work out a way to still allow me to pull the steer tube extension off whilst keeping the head set tensioned.

    Derek

  9. #9
    Senior Member
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    you could use a 28.6mm seat clamp on the steerer tube, to keep the headset on.

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