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  1. #1
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    Why not 29er forks for 650B?

    Why not use a 29er fork for 650B conversions? I have an 08 Giant Rincon and a lot of good spare stuff except a fork. My girlfriend wants to ride with me and being the bike snob I am and being into trying new things I figured why not try 650B? I've tried everything else, for instance single speed 5" travel FS really sucks lol.

    Now as to my question, why is everyone trying to make 26er forks work and buying 26er forks in hope that they work when a 29er fork clearly will work? I understand geometry is an important factor but if your bike is like my Rincon and came with a 100mm Suntour, why not just get a 80mm 29er fork?

    I'm not particularly well versed in frame geometry but my understanding is that as long as the static axle to crown and offset measurements remain unchanged, everything else is irrelevant. Am I missing something?

    I just measured a SR XCM100 Axle to Crown at 482mm and my Reba 29 80mm at 490mm, Fox F80 29 RLC at 481mm.
    Last edited by GTR-33; 09-27-2009 at 07:36 PM.

  2. #2
    Doesntplaywellwithmorons!
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    No reason except that then you sacrifice wheel travel, something you don't actually have to do with many 26er forks which can clear 650Bs. Right now basically the longest travel production 29er fork is 120mm travel. With 650B, pretty much every freeride/DH 26er fork that was meant to clear 26 x 2.7 will work with 650Bs as well as a great many shorter travel XC/All Mountain forks. The fork compatibility thread is full of the ones which are known to work with them. 29er suspension forks also cost a fair penny, even used, because there are so few of them available. 26er forks on the other hand... you can get the Rockshox Psylo forks for under $100 usually, even in immaculate condition and they have plenty of clearance to spare, and that's a 125mm travel fork.
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  3. #3
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by GTR-33
    Why not use a 29er fork for 650B conversions? I have an 08 Giant Rincon and a lot of good spare stuff except a fork. My girlfriend wants to ride with me and being the bike snob I am and being into trying new things I figured why not try 650B? I've tried everything else, for instance single speed 5" travel FS really sucks lol.

    Now as to my question, why is everyone trying to make 26er forks work and buying 26er forks in hope that they work when a 29er fork clearly will work? I understand geometry is an important factor but if your bike is like my Rincon and came with a 100mm Suntour, why not just get a 80mm 29er fork?

    I'm not particularly well versed in frame geometry but my understanding is that as long as the static axle to crown and offset measurements remain unchanged, everything else is irrelevant. Am I missing something?

    I just measured a SR XCM100 Axle to Crown at 482mm and my Reba 29 80mm at 490mm, Fox F80 29 RLC at 481mm.
    The thing you need to watch is the change in the total fork/tire height. Basically you do not want it to change from the stock dimension.

    If you are fitting 650B wheels front and rear you need only worry about the fork axle to crown (A-C) length.

    With a B on the front only the fork A-C needs to be ~12mm shorter than stock.

    If you did the latter with a 29er fork the travel would need to be 40-45mm shorter than the stock fork to maintain the stock bike geometry and handling.
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  4. #4
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    Just stick it on the back of a 29er. Some times I don,t think you need that big wheel in the back. The only drawback is it lowers your BB height.

  5. #5
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    Hi i know this is an old thread but i just got me a hand me down 650B frame that's designed for 650B/120mm travel forks? Would it be an issue if i got a rigid 29er cromo fork and use 29"/700cc wheels front/back? I dun have anything on hand except the frame, hydro disc brakes/rotors and rigid 650B forks are nowhere to be found where i'm at

  6. #6
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    Quote Originally Posted by hodak View Post
    Hi i know this is an old thread but i just got me a hand me down 650B frame that's designed for 650B/120mm travel forks? Would it be an issue if i got a rigid 29er cromo fork and use 29"/700cc wheels front/back? I dun have anything on hand except the frame, hydro disc brakes/rotors and rigid 650B forks are nowhere to be found where i'm at
    29er front wheel. 27.5 rear wheel.

  7. #7
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    It is easy to find 26" forks with straight steerer tubes on closeout. It is hard to find straight steerer tube forks that match up to a lot of the original 650b frames like a jamis dragon.

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