Okay, I’m wondering about something. As I understand it, the pedals are
threaded in different directions to help keep them from unscrewing
themselves as you ride. The R pedal screws onto the crank arm in a
clockwise direction, while the L pedal screws on counter-clockwise. But,
turn your uni’s pedals as they would go if you were riding forward, and
watch how the pedals and arms move in relation to each other. The R crank
for example turns clockwise while the pedal remains horizontal, giving the
same effect as turning the pedal counter-clockwise, which is actually
encouraging it to loosen rather than tighten. What’s up with this hey?
It does seem that they got the threads backwards, but it is threaded that
way for a reason. See http://www.sheldonbrown.com/gloss_p.html#pedal for
an explanation.
john_childs
>From: ickyslug@aol.complexity (Joe)
>
>Okay, I’m wondering about something. As I understand it, the pedals are
>threaded in different directions to help keep them from unscrewing
>themselves as you ride. The R pedal screws onto the crank arm in a
>clockwise direction, while the L pedal screws on counter-clockwise. But,
>turn your uni’s pedals as they would go if you were riding forward, and
>watch how the pedals and arms move in relation to each other. The R crank
>for example turns clockwise while the pedal remains horizontal, giving
>the same effect as turning the pedal counter- clockwise, which is
>actually encouraging it to loosen rather than tighten. What’s up with
>this hey?
>
>
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On 02 May 2001 06:27:01 GMT, Joe <ickyslug@aol.complexity> wrote:
>
> Okay, I’m wondering about something.
<skip description>
> the pedal remains horizontal, giving the same effect as turning the
> pedal counter-clockwise, which is actually encouraging it to loosen
> rather than tighten. What’s up with this hey?
The predominant effect is not a pure rotation about the axis of the pedal
(which is as you describe). The high perpendicular loading rotating around
the axis has a larger effect and tends to tighten the pedals. It’s very
hard to see why, but it’s true (and with some twiddling of some suitable
threads you can demonstrate it).
regards, Ian SMith
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>It does seem that they got the threads backwards, but it is threaded that
>way for a reason. See http://www.sheldonbrown.com/gloss_p.html#pedal for
>an explanation.
>
Ah. It is indeed clear to me now. Thank you.