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  1. #1
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    Fork Swap... Manufacturer's Thinking

    With all the fork swap threads (both to rigid and suspension), the talk has brought up a question about the axle-to-crown height. Not sure I can ask this question so you smart folks can understand but here is may attempt.

    Question is dealing with swapping a suspension fork to rigid, looking for the ideal axle-to-crown height of the final fork:
    Where in the travel of the susp fork is the ideal rigid fork length? Is it a complicated formula like the susp fork's average location durning rides that the bike was designed for with the average weight rider? Or something simpler like mid travel of the previous susp fork (if 100mm travel, then ridged would the length at 50mm)?
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  2. #2
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    Quote Originally Posted by coopdad View Post
    With all the fork swap threads (both to rigid and suspension), the talk has brought up a question about the axle-to-crown height. Not sure I can ask this question so you smart folks can understand but here is may attempt.

    Question is dealing with swapping a suspension fork to rigid, looking for the ideal axle-to-crown height of the final fork:
    Where in the travel of the susp fork is the ideal rigid fork length? Is it a complicated formula like the susp fork's average location durning rides that the bike was designed for with the average weight rider? Or something simpler like mid travel of the previous susp fork (if 100mm travel, then ridged would the length at 50mm)?
    You can take your atoc measurement and subtract sag , or some manufactures of rigid forks (surly) specify what their fork is designed for or you can do a google MTBR search for conversions as this gets asked quite often. Getting the rake right also comes into play as a Vintage Manitou might be 38mm and a Marzocchi 45mm. You may also want to play with those numbers if you want to change the handling of a bike to steer slower or faster. Is your fork original equipment to your bike?

  3. #3
    Schipperkes are cool.
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    figure Sag to be 17-25% of the stroke.
    Quote Originally Posted by mikesee
    Better suited to non-aggressive 125# gals named Russell.

  4. #4
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    I recently swapped a 120mm travel fork with a "corrected 100mm" rigid, the bike feels great, no weird handling issues, however I am having issues with bottom bracket height now, touching pedals on familiar trails where I never touched before. My $.02

  5. #5
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    I actually was wondering the frame designer's thoughts more than actual numbers. I mean, a designer will have an ideal geometry in mind when designing. Rigid would allow him to build it in exactly, suspended would be all about the compromise, knowing it would be ideal on at certain times. Wondering about that grey area.

    Sorry all for being such a noob (not searching).
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  6. #6
    Schipperkes are cool.
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    Quote Originally Posted by Gp.plus View Post
    , no weird handling issues, however I am having issues with bottom bracket height now, touching pedals on familiar trails where I never touched before.
    Sounds like a weird handling issue
    Quote Originally Posted by mikesee
    Better suited to non-aggressive 125# gals named Russell.

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