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  1. #1
    Lyen lyen's Avatar
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    Dahon Speed Pro extreme carbon fiber fork modification

    This is modification that I have found for the Speed Pro from a Chinese Shanghai bike forum. I believe it can also apply to a lot of folding bikes we have. I just could not resist to share. Very interesting.
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  2. #2
    Smiling and Waving thebikeguy's Avatar
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    It seems like quite the major surgery for a small outcome.What would be the reasoning?To lose some weight off the front?Seems like it would be kinda minimal.

  3. #3
    Wheelsuck Fat Boy's Avatar
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    Do you notice a difference in ride?

    Your new fork looks great.

  4. #4
    Lyen lyen's Avatar
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    This is not a small outcome. The main reason is because the carbon fiber fork does reduce the bump on the road in addition to the weight reduction. It kind of duplicate the effect of the Kinetix Pro S's built-in suspension hub. Therefore, you dramatically reduced the weight of both the steel fork + the suspension hub. If you have ever rode a bike with CF fork, you then will get the idea of a real performance road bike & you will never go back. Plus if you look carefully on the picture, the SRAM dual speed hub was also gone. The whole bike is now only 17.54lbs (7955 gram) instead of the original with 24lbs. This is a real folding weight wheelie.

  5. #5
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    i applaud the inventiveness and effort but I'd rather eat some protein and do a few extra dumb bell curls to deal with the speed pro's weight (which i find pretty light anyway)

  6. #6
    Raleigh20 PugFixie, Merc LittlePixel's Avatar
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    I'd be interested to know about how the dropouts were re-applied. This is the sort of thing that might seem silly as a weight saving exercise, but it's the sort of thing one can do at home a little more easily than shortening steel forks, which interests me greatly with a stripped Twenty frame in the shed awaiting a conversion to 520 wheels. All you need is a dremel, some glue and patience as opposed to the full brazing / welding caboodle...

    The spacing thing is a bit more odd - perhaps a new hub might have worked better?

  7. #7
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    carbon fork

    Also intestests me after seeing this article showing a Bike Friday with cut down carbon fork (among other innovations).

    http://www.bikefriday.com/node/6056

    Evidently it's doable, but it remains to find a narrow width fork for Brommie's.

    Easier still, the Hasa Minimax (20" all carbon) also has a carbon fork; so forks are in production.

  8. #8
    jur
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    I have been thinking about exactly this sort of mod for my Swift. I have a spare set of forks but the major unsolved problem is the forks spacing gets narrower as you go up, and so the existing hub would not fit. The above mod uses a Dahon hub so he was fine with a few spacers. I need "unspacers". This mod would be great for the Swift as I stand to lose roughly 1/2kg. I have been wondering if a hub could be cut through the middle so it ends up narrower, and what the various issues might be. I'm clueless here.

  9. #9
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    20" carbon fork

    Did a quick web check, and there are 20" carbon forks out there, though most oriented towards BMW and for 1" width. Manitou Answer for example has several.

    Found specs for the Hasa fork; it's: Saga CB-F01N 1-1/8" A-head for 20" MTB, carbon.

    Can't find anything about "Saga" brand. Must be others out there.

  10. #10
    Lyen lyen's Avatar
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    LittlePixel, the dropouts were re-apllied by simply bond the pieces together with resin. This is a material you can easily get to make fiberglass. I agreed with you and Jur that the spacing is kind of rare since it was made out of a 700c CF fork. Unless we can get a Hasa Minimax 20" carbon fork from Bangkok in Thailand that has the correct spacing with about 75-80mm dropout, this is the only way to go as of today. The primary goal is to get the feel of carbon fork + save weight. I believe someone can come up with better ideas in the future.

  11. #11
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    the forks are out there

    The Hasa is made in TW/Taiwan, and one may assume components are sourced from TW as well.

    Google it and you will see there are carbon forks for 20" wheels out there; the Hasa is just an example of one in standard 20" MTB format. The trick now is to source from TW or elsewhere for an appropriate fork for your requirements.

    On the web I also came across a 2005 Bike Friday that came with carbon forks from the factory.

  12. #12
    Edd
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    Hi Iyen,

    I have used carbon extensively in making kayaks and paddles and I am always amazed at the quality of bikes and components made from carbon fibre. The appearance and quality control is first rate. What really impresses me is the engineering and experience in the actual implementation. After seeing the first hand sudden destruction of carbon fibre shafts I would be very wary of modifying these carefully designed forks because failure could be sudden and catastrophic. Some things to consider are the problems of bonding metal to composite, reaction of dissimilar materials and fatigue. The outer circumference of the fork may be strengthened by a wrap of kevlar, this is often applied to paddle shafts with internal spigots.

    Edd

  13. #13
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    Quote Originally Posted by jur View Post
    I have been wondering if a hub could be cut through the middle so it ends up narrower
    Steve Parry regularly does it but I would be speculating about the effects.

  14. #14
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    Another 20" bike with stock carbon fork is Tyrell Si ... but no v-brake boss in place.

    http://www.tyrellbike.com/si.html

    Now if I could just find ... in my dreams I suspect ... a carbon fork for a Brompton.

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