Low or high gear causes wheel slippage?

Discussion in 'Cycling Equipment' started by Phil, Squid-in-Training, Sep 8, 2005.

  1. In a.m-b, we've mentioned singlespeeds and how the wheel sometimes slips
    with a quick-release skewer. We got into gear ratio discussion, and I
    maintained that high gears cause more wheel slippage since less of the pedal
    force is being turned into torque and more is being turned into wheel
    translation force. Low gears cause more torque and therefore slip less.

    This is what I think... is it correct? I'm sure none of you have had the
    wheel slip at a high cadence (not the cause but the general effect).

    --
    Phil, Squid-in-Training
     
    Tags:


  2. Kinky Cowboy

    Kinky Cowboy Guest

    On Thu, 8 Sep 2005 18:23:26 -0400, "Phil, Squid-in-Training"
    <phil_leeIHEARTBASHGUARDS@hotmail.com> wrote:

    >In a.m-b, we've mentioned singlespeeds and how the wheel sometimes slips
    >with a quick-release skewer. We got into gear ratio discussion, and I
    >maintained that high gears cause more wheel slippage since less of the pedal
    >force is being turned into torque and more is being turned into wheel
    >translation force. Low gears cause more torque and therefore slip less.
    >
    >This is what I think... is it correct? I'm sure none of you have had the
    >wheel slip at a high cadence (not the cause but the general effect).


    Gear ratio is irrelevant, what matters is chain tension. For a given
    pedal load, this increases for longer cranks and smaller chainrings.
    You'll pull the wheel less on 40/20 than on 32/16; same ratio, but the
    bigger ring reduces the chain tension by 20%. Slip occurs at low
    speeds because this is when the human exerts the greatest pedal loads.

    Kinky Cowboy

    Modernity consists in the substitution
    for the immediate of the instantaneous
     
  3. On Thu, 8 Sep 2005 18:23:26 -0400, "Phil, Squid-in-Training"
    <phil_leeIHEARTBASHGUARDS@hotmail.com> wrote:

    >In a.m-b, we've mentioned singlespeeds and how the wheel sometimes slips
    >with a quick-release skewer. We got into gear ratio discussion, and I
    >maintained that high gears cause more wheel slippage since less of the pedal
    >force is being turned into torque and more is being turned into wheel
    >translation force. Low gears cause more torque and therefore slip less.
    >
    >This is what I think... is it correct? I'm sure none of you have had the
    >wheel slip at a high cadence (not the cause but the general effect).


    Torque is *turning force*. It doesn't cause the wheel to move horizontally
    at all. What causes the wheel to move horizontally is that the torque is
    generated by the chain pulling to the front at a distance from the axle
    (depending on cog there, distance is greater or smaller), and the axle
    clamping providing a force (hopefully) equal and opposite (but not acting
    at the same point). So to sum up, what matters is the (maximum) chain
    tension, not torque. And maximum chain tension scales directly with the
    chainring size. In small chainrings, you've got a lot of leverage, and you
    can turn your weight into much more chain tension.

    So: The front gear matters, the rear one doesn't.


    Jasper
     
  4. Werehatrack

    Werehatrack Guest

    On Thu, 8 Sep 2005 18:23:26 -0400, "Phil, Squid-in-Training"
    <phil_leeIHEARTBASHGUARDS@hotmail.com> wrote:

    >In a.m-b, we've mentioned singlespeeds and how the wheel sometimes slips
    >with a quick-release skewer. We got into gear ratio discussion, and I
    >maintained that high gears cause more wheel slippage since less of the pedal
    >force is being turned into torque and more is being turned into wheel
    >translation force. Low gears cause more torque and therefore slip less.
    >
    >This is what I think... is it correct? I'm sure none of you have had the
    >wheel slip at a high cadence (not the cause but the general effect).


    All transmission of energy from the cranks to the wheel is done by
    linear tension in the chain; the higher the chain tension, the higher
    the force pulling the wheel forward. Therefore, the smaller the front
    sprocket (regardless of the rear sprocket size), the more force that
    will be exerted to dislocate the rear wheel during highest-force
    pedalling. It's a simple matter of leverage ratios.

    (Addendum: the rear sprocket size can limit the highest force
    actually achieved; the larger the rear sprocket, the greater the
    leverage that it has on the wheel, which will presumably then rotate
    and consume the transmitted power, limiting the amplitude of the
    impulse. If the wheel cannot rotate, then the chain tention is
    determined entirely by the magnitude and vector of the force applied
    to the pedal, the crank position, and the front sprocket size.)
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.
     
Loading...

Share This Page

Loading...