should the uphills be steep - or the downhills?

Discussion in 'Cycling Equipment' started by Larry English, Jun 20, 2003.

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  1. say you wanted to go on a trip from home.

    the route has some hills.

    these hills are unusual.

    as you leave home, all the downhills are steep, but climbing back up each one is a long
    gentle slope.

    you will take the same way back.

    which way would you expect to be faster and why?

    wle.
     
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  2. Ken

    Ken Guest

    [email protected] (larry english) wrote in news:abbf1007.0306200756.617565d5 @posting.google.com:
    > as you leave home, all the downhills are steep, but climbing back up each one is a long
    > gentle slope.
    >
    > you will take the same way back.
    >
    > which way would you expect to be faster and why?

    That depends on:
    1. how good a climber you are
    2. how good a descender you are
    3. how easy the descents are (smooth roads, good visibility, banked turns)
     
  3. Harris

    Harris Guest

    "larry english" wrote:
    > say you wanted to go on a trip from home. the route has some hills. these hills are unusual. as
    > you leave home, all the downhills are steep, but climbing back up each one is a long gentle slope.
    > you will take the same way back. which way would you expect to be faster and why?

    The trip back should be faster, though maybe not as much fun.

    On the way out: Going down the steep hills will probably require you to brake, and the braking will
    convert kinetic energy into heat. Aerodynamic losses will also be greater on the steep descents.

    On the way back: Assuming you pace yourself on the steep climbs, and use appropriate gears, your
    legs shouldn't seize up. And you'll cruise down the gentle descents without much braking. Much less
    energy lost this way.

    Art Harris
     
  4. "Harris" <[email protected]> wrote in message
    news:<[email protected]>...
    > "larry english" wrote:
    > > say you wanted to go on a trip from home. the route has some hills. these hills are unusual. as
    > > you leave home, all the downhills are steep, but climbing back up each one is a long gentle
    > > slope. you will take the same way back. which way would you expect to be faster and why?
    >
    > The trip back should be faster, though maybe not as much fun.
    >
    > On the way out: Going down the steep hills will probably require you to brake, and the braking
    > will convert kinetic energy into heat. Aerodynamic losses will also be greater on the steep
    > descents.
    >
    > On the way back: Assuming you pace yourself on the steep climbs, and use appropriate gears, your
    > legs shouldn't seize up. And you'll cruise down the gentle descents without much braking. Much
    > less energy lost this way.

    ok, that's good.

    but - i neglected to say, no braking is required.

    and maybe it can;t be answered, without knowing how good a climber one is.

    assume, average climbing ability, does that help?

    wle.

    >
    > Art Harris
     
  5. "larry english" <[email protected]> wrote in message
    news:[email protected]...
    > "Harris" <[email protected]> wrote in message
    news:<[email protected]>...
    > > "larry english" wrote:
    > > > say you wanted to go on a trip from home. the route has some hills. these hills are unusual.
    > > > as you leave home, all the downhills are steep, but climbing back up
    each
    > > > one is a long gentle slope. you will take the same way back. which way would you expect to be
    > > > faster and why?
    > >
    > > The trip back should be faster, though maybe not as much fun.
    > >
    > > On the way out: Going down the steep hills will probably require you to brake, and the braking
    > > will convert kinetic energy into heat.
    Aerodynamic
    > > losses will also be greater on the steep descents.
    > >
    > > On the way back: Assuming you pace yourself on the steep climbs, and use appropriate gears, your
    > > legs shouldn't seize up. And you'll cruise down
    the
    > > gentle descents without much braking. Much less energy lost this way.
    >
    > ok, that's good.
    >
    > but - i neglected to say, no braking is required.
    >
    > and maybe it can;t be answered, without knowing how good a climber one is.
    >
    > assume, average climbing ability, does that help?
    >
    > wle.

    Troublemaker. ;-) Depends on a lot of variables, but assuming your scenario is a non-technical
    out-n-back, where the descents are twice as steep as the climbs on the way out and the reverse on
    the return, you would be faster on the way out. This assumes a constant power output both up AND
    down the hills (say 270 watts) and a small frontal area reduction from tucking on the descents.

    Yeah, I cheated... www.analyticcycling.com
     
  6. but what if your destination was the workplace/office? me? i'm always late so i might imagine i
    would be in a rush one way, and at the end of the day, i would make it a leisurely ride. especially
    since it's cool in the morning and triple digits in the late day.

    ???

    eric

    fresno, ca.

    > From: "Steve Blankenship" <[email protected]> Newsgroups: rec.bicycles.tech Date:
    > Fri, 20 Jun 2003 21:29:39 -0400 Subject: Re: should the uphills be steep - or the downhills?
    >
    > "larry english" <[email protected]> wrote in message
    > news:[email protected]...
    >> "Harris" <[email protected]> wrote in message
    > news:<[email protected]>...
    >>> "larry english" wrote:
    >>>> say you wanted to go on a trip from home. the route has some hills. these hills are unusual. as
    >>>> you leave home, all the downhills are steep, but climbing back up
    > each
    >>>> one is a long gentle slope. you will take the same way back. which way would you expect to be
    >>>> faster and why?
    >>>
    >>> The trip back should be faster, though maybe not as much fun.
    >>>
    >>> On the way out: Going down the steep hills will probably require you to brake, and the braking
    >>> will convert kinetic energy into heat.
    > Aerodynamic
    >>> losses will also be greater on the steep descents.
    >>>
    >>> On the way back: Assuming you pace yourself on the steep climbs, and use appropriate gears, your
    >>> legs shouldn't seize up. And you'll cruise down
    > the
    >>> gentle descents without much braking. Much less energy lost this way.
    >>
    >> ok, that's good.
    >>
    >> but - i neglected to say, no braking is required.
    >>
    >> and maybe it can;t be answered, without knowing how good a climber one is.
    >>
    >> assume, average climbing ability, does that help?
    >>
    >> wle.
    >
    > Troublemaker. ;-) Depends on a lot of variables, but assuming your scenario is a non-technical
    > out-n-back, where the descents are twice as steep as the climbs on the way out and the reverse on
    > the return, you would be faster on the way out. This assumes a constant power output both up AND
    > down the hills (say 270 watts) and a small frontal area reduction from tucking on the descents.
    >
    > Yeah, I cheated... www.analyticcycling.com
     
  7. Whitfit

    Whitfit Guest

    eric paul zamora <[email protected]> wrote in message
    news:<BB19686E.9B92%[email protected]>...

    > > Troublemaker. ;-) Depends on a lot of variables, but assuming your scenario is a non-technical
    > > out-n-back, where the descents are twice as steep as the climbs on the way out and the reverse
    > > on the return, you would be faster on the way out. This assumes a constant power output both up
    > > AND down the hills (say 270 watts) and a small frontal area reduction from tucking on the
    > > descents.
    > >
    > > Yeah, I cheated... www.analyticcycling.com
    > >
    > >

    I disagree- I find that short steep uphills are much faster with the long descents, bacause you can
    ride harder on the uphills, because you can rest on the downhills, and they are over quicker. I
    also find the
    psychology better- I hate long, medium slope uphills, and I like short steep ones. So, maybe
    it's personal.

    Whitfit.
     
  8. Harris

    Harris Guest

    "Steve Blankenship" wrote:
    > Troublemaker. ;-) Depends on a lot of variables, but assuming your
    scenario
    > is a non-technical out-n-back, where the descents are twice as steep as
    the
    > climbs on the way out and the reverse on the return, you would be faster
    on
    > the way out. This assumes a constant power output both up AND down the hills (say 270 watts) and a
    > small frontal area reduction from tucking on
    the
    > descents.

    In real life, I doubt most people would put out as much power when descending a steep hill as
    when climbing.

    Also, I guess we have to assume that the "turn-around point" is at the same altitude as the
    start/finish.

    Now, what if we were doing this on the moon instead? ;->

    Art Harris
     
  9. "Harris" <[email protected]> wrote in message
    news:jc%[email protected]...

    > In real life, I doubt most people would put out as much power when descending a steep hill as when
    > climbing.
    >
    > Also, I guess we have to assume that the "turn-around point" is at the
    same
    > altitude as the start/finish.
    >
    > Now, what if we were doing this on the moon instead? ;->
    >

    If we were doing this on the moon, then maybe I could actually climb! ;-)

    SB (who needs air?)
     
  10. "whitfit" <[email protected]> wrote in message
    news:d5[email protected]...

    > I disagree- I find that short steep uphills are much faster with the long descents, bacause you
    > can ride harder on the uphills, because you can rest on the downhills, and they are over quicker.
    > I also find the
    > psychology better- I hate long, medium slope uphills, and I like short steep ones. So, maybe it's
    > personal.

    Certainly depends on your relative effort in each direction, but not assuming some constants (like
    output & turnaround elevation) makes coming up with an answer futile. And requires that you factor
    in such "noise" into your data as how encountering comely female rollerbladers en route might affect
    your speed... ;-)

    Besides; haven't run the numbers, but if you ride the climbs hard and rest/coast the downhills, I'd
    guess the ez/climb steep descent would probably win by even more. For purposes of this problem, you
    can ignore the flats and just look at it as a one-hill situation; one side steep the other mild,
    with both sides having the same vertical gain - in which direction would a given effort result in a
    quicker time.

    SB
     
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