seat post height?

songwriter Posts: 109
edited December 2007 in Road beginners
Is there a golden rule? Must your leg extend straight to the pedal with a parallel foot to the floor?
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  • Smokin Joe
    Smokin Joe Posts: 2,706
    The knee should still have a bend in it when the pedal is at it's lowest point, you've run out of power by the time the leg is completely straight. There are plenty or articles on the net that deal with positioning, Sheldon brown is a site worth checking out.
  • dennisn
    dennisn Posts: 10,601
    Sit on the bike with one foot clipped in. Put the heel of your other foot on the other
    pedal. With that pedal all the way down at 6 oclock your leg should be almost fully
    extended. Move the saddle up or down if it isn't. This will allow for the proper bend in your leg when you are clipped in. Smoken Joe is right on in saying that you don't want
    your legs to be fully extended when you ride. There needs to be some knee bend at the bottom of the pedal stroke. Spinning is really hard if you have your legs fully extended
    and to much bend at the bottom makes your thighs work harder than need be.

    dennis Noward
  • feel
    feel Posts: 800
    Hi songwriter if you are checking your seat height also worth checking its fore & aft position. When your feet are in the quarter past nine position they usually reckon the bone just below your knee cap on your front leg should be vertically above the spindle of that pedal. The easiest way to check is to get someone to take a digital photo of you on the bike.
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  • Cajun
    Cajun Posts: 1,048
    Saddle Height
    With the right frame size, you'll be able to set your correct saddle height, which will be within a centimeter of .883 x inseam length, measured from the center of the bottom bracket to the low point of the top of your saddle. This allows full leg extension, with a slight bend in the leg at the bottom of the pedal stroke.

    LeMond recommends that you then shorten this length by 3mm when using clipless pedals. Also, you might consider a slightly taller saddle height if you ride with your toes down and your heel raised. Most importantly, make any changes in saddle height gradually, and give your body time to adapt to the new position.
  • John.T
    John.T Posts: 3,698
    Get someone to ride behind you and check if your pelvis is rocking on the saddle. If so it is too high. The heel on the pedal method is a good starting point but it is only that. If you tend to ride toes down it will be too low, if heel down then maybe too high. Your saddle should be as high as you can ride comfortably with no pelvis rock. Too high or too low and you will loose power.
    The knee over pedal spindle is also only a good starting point. We all ride and are built differently so no formula will work to find the 'best' position, only a starting point.
  • Mettan
    Mettan Posts: 2,103
    Also keep an eye on your saddle height in relation to knee joint forces - too low and it'll substantially increase patella-femoral forces, too high and it'll add increased strain on your cruciate ligaments.