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  1. #1
    Still learning
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    Dec 2006
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    Doing everything possible to fix knee problems

    Ever since I built up my new XC rig, I've been having knee problems. We've looked at all kinds of things to get the positioning correct, and for while it seemed okay, but since the problems have returned.
    Everything in terms of seat height and saddle fore/aft position we've already tweaked and spend a lot of time on. However, things now point to cleat position. On the XC rigs I'm ditching XPedo pedals to go back to Shimano pedals, as I never had problems before I went to XPedos. Float on the XPedos is a measly 4 degrees, whereas on the Shimanos (various models) its in the 12 to 15 degree range.

    I've just done some measurements between my road and mountain bikes, and noticed something which could be a concern.

    On the road bike (Giant TCR A2), I don't really have any knee problems, though my hips do start to hurt a bit.
    My two XC bikes are an Giant XTC and a Giant Talon.

    The Talon has never really caused me too much trouble, and geometry there we think is pretty right, except that I've barely ridden it since putting XPedo pedals on, so it's hard to tell.
    Basically, the one measurement I just paid attention to was the distance between the inside ball of my foot to the center of the frame. The measurements were frighteningly different, and what I want to know is if this is any cause for concern. I can see how it would affect how your knee twists and works under load:

    TCR: 83mm
    XTC: 98mm
    Talon: 103mm - Keep in mind I've not ridden this enough since putting XPedo pedals on though. Position on the Shimano M505s seems to be about 3mm further outwards (which would make this figure 106mm in a position which never gave me problems).

    That kinda throws the theory is that the Talon is further out yet might be okay.

    Toe-in on both the road and XC bikes is similar, though I have not actually measured this angle.

    I'm after any input here which might help resolve this. It's a problem I desperately want solved before State round 1 and the 24 hour in 3 weeks time (State won't give me a problem, as the knee doesn't give problems on <3 hour rides, but the 24 hour the week before will destroy it).

  2. #2
    mtbr member
    Reputation: California L33's Avatar
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    Jul 2005
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    699
    It might have something to do with float. 4 degrees isn't much. I didn't know you could get Smimano pedals with 15 degrees of float. Are they spring centering designs by any chance? If so you might want to forget about them and try Speedplay Frogs. I credit properly adjusted Frogs with keeping me riding. They feel a little weird at first because nothing is pulling at you, but that's just what you want.

    One other possibility that I didn't see you consider is the different way people ride mountain than road. You tend to spend more time loading the pedals, and going up steep trails puts more load on your legs than the steepest hill a roadie will encounter.
    To the troll mobile, away...

  3. #3
    mtbr member
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    #1 Change pedals and increase float. I like Crank Bros.

    #2 Try moving your saddle fore and aft. It's free and if it helps,you will be happy you found a better riding position.

  4. #4
    mtbr member
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    What type of knee problems and where abouts? Is it just one knee? any old injuries etc?

  5. #5
    fnar fnar brrraaaaap
    Reputation: ilostmypassword's Avatar
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    Dec 2006
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    2,171
    I had teh same problem and I advise that you

    1. Increase float with a) Crank Bro OR 2) Time attack

    Time Attack will give you more years..... as they dont wear out when you look at them like crank bros.

    2. Work on your core body strength to take away some of the suffering from below the waist line!

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