High-40s/Low50's riding: more or less efficient than 70s/80s?

Discussion in 'Cycling Equipment' started by (Pete Cresswell), Dec 19, 2004.

  1. [email protected] wrote:
    > Dear Pete,
    >
    > It's not your imagination. Riders usually go slower as the
    > temperature drops for several reasons.
    >
    > A) Temperature comfort--going slower reduces wind chill
    > B) Breathing comfort--cold air is denser, but much less fun
    > C) Clothing aerodynamics--winter clothes = wind drag
    > D) Raw wind drag--density affects drag more than breathing
    >
    > The wind drag of the denser cold air is probably the biggest
    > factor.


    This is probably true. Drag force is proportional to air density,
    which (using the ideal gas law) increases by 1% for each 3C
    decrease in temperature.

    The list is missing rolling resistance of the tires, though.
    The new edition of Bicycling Science suggests that rolling
    resistance increases by 1% for each 1C decrease in temperature.

    Not that these are huge effects, but they do reinforce my own
    biases. I like to ride when it is hot.

    Dennis Ferguson
     


  2. [email protected] wrote:
    > Dear Pete,
    >
    > It's not your imagination. Riders usually go slower as the
    > temperature drops for several reasons.
    >
    > A) Temperature comfort--going slower reduces wind chill
    > B) Breathing comfort--cold air is denser, but much less fun
    > C) Clothing aerodynamics--winter clothes = wind drag
    > D) Raw wind drag--density affects drag more than breathing
    >
    > The wind drag of the denser cold air is probably the biggest
    > factor.


    This is probably true. Drag force is proportional to air density,
    which (using the ideal gas law) increases by 1% for each 3C
    decrease in temperature.

    The list is missing rolling resistance of the tires, though.
    The new edition of Bicycling Science suggests that rolling
    resistance increases by 1% for each 1C decrease in temperature.

    Not that these are huge effects, but they do reinforce my own
    biases. I like to ride when it is hot.

    Dennis Ferguson
     
  3. [email protected] wrote:
    > Dear Pete,
    >
    > It's not your imagination. Riders usually go slower as the
    > temperature drops for several reasons.
    >
    > A) Temperature comfort--going slower reduces wind chill
    > B) Breathing comfort--cold air is denser, but much less fun
    > C) Clothing aerodynamics--winter clothes = wind drag
    > D) Raw wind drag--density affects drag more than breathing
    >
    > The wind drag of the denser cold air is probably the biggest
    > factor.


    This is probably true. Drag force is proportional to air density,
    which (using the ideal gas law) increases by 1% for each 3C
    decrease in temperature.

    The list is missing rolling resistance of the tires, though.
    The new edition of Bicycling Science suggests that rolling
    resistance increases by 1% for each 1C decrease in temperature.

    Not that these are huge effects, but they do reinforce my own
    biases. I like to ride when it is hot.

    Dennis Ferguson
     
  4. Mark Hickey

    Mark Hickey Guest

    "Dennis Ferguson" <[email protected]> wrote:

    >The list is missing rolling resistance of the tires, though.
    >The new edition of Bicycling Science suggests that rolling
    >resistance increases by 1% for each 1C decrease in temperature.
    >
    >Not that these are huge effects, but they do reinforce my own
    >biases. I like to ride when it is hot.


    Hmmmm, taking into account my current winter speed at about 5 degrees
    C, come the next Arizona summer I should be passing all the cars on
    the interstate! ;-)

    Mark Hickey
    Habanero Cycles
    http://www.habcycles.com
    Home of the $695 ti frame
     
Loading...
Loading...