Cycling Equipment · Public discussion

propulsive forces tacking to climb hill

Started by Ken Roberts · · Last activity · 16 posts · 696 views

Thread navigation

Jump through the discussion

Go to the original post, the replies on this page, or the latest preserved contribution.

Thread details

What we know about this thread

Original section
Cycling Equipment
Published
2 November 2007
Last activity
6 November 2007
Original author
Ken Roberts
Posts
16
Discussion status
Public discussion
Total views
696
Views / 30 days
0

The navigation and discussion metadata provide context. Posts remain in their original chronological order.

Showing posts 1–16 of 16
Posts remain in their original chronological order.

Text size
  1. While "tacking" to climb up a steep hill, I found some moves different from
    normal cycling to help me get up the hill easier: swinging my shoulders
    sideways up the hill, and using my arms to "sweep" my wheels directly
    sideways toward down the hill. It enabled me to survive a long steep hill --
    and doing it made the climbing sorta fun.

    By "tacking" I mean turning my bike diagonally off my overall direction of
    forward motion, then turning my bike again to go diagonally toward the other
    side, and repeating to make a sort of curved zig-zag path. Of course I would
    only do this when I have lots of road-width available with no other vehicles
    using it. Using a "tacking" path can make it easier to climb up a steep hill
    by spreading a fixed vertical gain over a much longer horizontal distance --
    effectively reducing the hill's steepness, and so reducing the minimum power
    output required to climb up it with losing control or stopping.

    The zig-zag path also offers some different opportunities to _add_ more
    propulsive work and power for the climbing. I found this out when I wanted
    to do this long steep climb on a rental bike that didn't have low gears.
    There was supposed to be an exciting descent on the other side that I wanted
    to try, but I knew I was going to have to "cheat" to get to the top without
    lots of walking. It was a remote area on a mid-week day with little car
    traffic, so I decided to try some "tacking". And that helped make it easier,
    as expected.

    In the midst of the climb I got the idea that I could take some burden off
    my leg muscles by directly "throwing" the weight of my upper body up the
    hill. While riding mostly sideways across the hill, just as I started my
    turn to go the other way, I swung my shoulders sideways up the hill. And
    that made it easier to pedal thru the turn -- which is the tough part of
    tacking up a steep hill. This worked for me while pedaling either standing
    or sitting. So I did those upper body move lots more. Then my abdominal
    muscles got tired from doing all that the sideways "tossing" -- it's not
    something I trained for. So I went back to simple pedaling, then did some
    more sideways tossing again later.

    With this new tool, now I can take on even steeper climbs, I thought. So the
    next day I decided to try the east side of Colle dell'Agnello on the
    Italy-France border. It's the third-highest paved mountain pass in Europe,
    used in the Giro d'Italia recently, sustained steeper than Stelvio (and much
    steeper than Alpe d'Huez), also an automated time-trial course. Until that
    day it was unimaginable that I could survive climbing it on a rental bike
    lacking ultra-low gears. I started early in the morning, very little
    traffic, and when I reached the sustained steep part I started tacking
    again, and some of the "sideways shoulder-tossing" move -- and then I
    thought to try another move:

    While pedaling sitting going diagonally across the road, just at the start
    of the turn to go the other way, I pushed my hand down on the uphill end of
    the handlebar, and pulled my hand up on the downhill end of the handlebar --
    which pushed my wheels directly sideways in the direction diagonally down
    the hill -- sort of "sweeping" the wheels under me from the uphill side to
    the downhill side (thus toward the outside of the turn I was going into). It
    definitely helped me get thru the zig-zag turn more easily. It felt really
    different to be pushing the wheel directly sideways. And it was fun to play
    with: different timing of the start and finish of the move relative to the
    turn, mixing it with the "sideways shoulder toss", standing versus sitting,
    tighter higher-frequency zig-zags. I was the first rider up to the pass, and
    I felt so good I rode part of the way down the other side into France and
    climbed back.

    This second "wheels side-sweep" move is different from tilting the bike from
    side while standing, because that purpose of that standing move is to add
    more force thru the _legs_ pushing on the pedals and drivetrain to help the
    wheels roll forward. This "wheels side-sweep" move also works while pedaling
    sitting, and transmits force thru the frame and axles directly to the wheels
    to push directly sideways, not thru the chain and cogs to roll forward. The
    physics is more like _skating_ than normal bicycling.

    On my descent I went by the other cylists climbing the "correct" way,
    straight up the road in low pedaling frequency, and there was no doubt it my
    mind that cheating with those strange moves was just more fun.

    Ken

  2. "Ken Roberts" wrote: While "tacking" to climb up a steep hill, I found some
    moves different from normal cycling to help me get up the hill easier:
    swinging my shoulders sideways up the hill, and using my arms to "sweep" my
    wheels directly sideways toward down the hill. (clip)
    ^^^^^^^^^^^^^^^^^^^
    I recently saw a guy going up a hill on a scooter doing something like this.
    This was not a normal scooter--it was V shaped, with one front wheel and two
    rear wheels, and he had one foot on each side of the V. He did not touch
    the ground with his feet at all, so the propulsion HAD to come from the way
    he was tacking and throwing his body weight back and forth.

    I haven't figured out why it works, and wouldn't have believed it if I
    hadn't seen it. I rolled my window down and said, "You can't do that," and
    he laughed.

  3. Leo Lichtman wrote

    Quoted message said:

    I recently saw a guy going up a hill on a scooter doing something like
    this.

    Strange things are out there. Probably there's a video of it somewhere.

    Here's a video of guy propelling himself on one skate (on the flat) by
    pushing it diagonally to one side and then the other.


    At first he does it with two skates on the ground, and it looks pretty
    believable -- feels like "I could do that, too". Then around time 1:08 he
    takes it to his limit.

    I wonder if riding a bicycle on smooth flat pavement, if you could propel
    yourself on a zig-zag path using only cleverly-timed sideways
    shoulder-shifts and pulling up and down on the handlebars for wheel
    side-force -- with no pedaling at all?

    Ken

  4. On Nov 2, 11:32 am, "Leo Lichtman" <[email hidden]>

    Quoted message said:

    "Ken Roberts" wrote: While "tacking" to climb up a steep hill, I found some

    moves different from normal cycling to help me get up the hill easier:
    swinging my shoulders sideways up the hill, and using my arms to "sweep" my
    wheels directly sideways toward down the hill. (clip)
    ^^^^^^^^^^^^^^^^^^^
    I recently saw a guy going up a hill on a scooter doing something like this.
    This was not a normal scooter--it was V shaped, with one front wheel and two
    rear wheels, and he had one foot on each side of the V. He did not touch
    the ground with his feet at all, so the propulsion HAD to come from the way
    he was tacking and throwing his body weight back and forth.

    http://www.razor-scooters.com/trikke-scooters/default.htm

  5. Ken Roberts said:
    Quoted message said:

    I recently saw a guy going up a hill on a scooter doing something
    like this.

    Quoted message said:

    Strange things are out there. Probably there's a video of it
    somewhere.

    Quoted message said:

    Here's a video of guy propelling himself on one skate (on the flat)
    by pushing it diagonally to one side and then the other.

    Quoted message said:

    At first he does it with two skates on the ground, and it looks
    pretty believable -- feels like "I could do that, too". Then around
    time 1:08 he takes it to his limit.

    Quoted message said:

    I wonder if riding a bicycle on smooth flat pavement, if you could
    propel yourself on a zig-zag path using only cleverly-timed sideways
    shoulder-shifts and pulling up and down on the handlebars for wheel
    side-force -- with no pedaling at all?

    Try it. You'll find just yoyoing the steering of your bicycle from
    side to side will propel it forward... slowly. Use a standing start.

    Jobst Brandt

  6. [email hidden] wrote

    Quoted message said:

    Try it. You'll find just yoyoing the steering of your bicycle from
    side to side will propel it forward... slowly. Use a standing start.

    Thanks, now I'm eager to see how it will feel.

  7. landotter wrote

    Quoted message said:

    http://www.razor-scooters.com/trikke-scooters/default.htm

    That Trikke looks like a very creative device. Not very expensive. It's
    tempting to try.

    On the other hand, I've already worked thru the learning curve with inline
    skates out on the roads, and I think they're more different from a
    bicycle -- so they offer me a greater variety of experience.

    .. (On the Trikke Comparison Chart, it looks to me like somebody got confused
    between percent grade and degrees, as a way to measure the steepness of a
    hill-climb.)

    Ken

  8. In article <WzHWi.16$9N6.13@trnddc03>,

    Ken Roberts said:

    By "tacking" I mean turning my bike diagonally off my overall direction of
    forward motion, then turning my bike again to go diagonally toward the other
    side, and repeating to make a sort of curved zig-zag path.

    FYI, this is more often referred to as switchbacks. For the obvious
    reason, see:

    http://en.wikipedia.org/wiki/Hairpin_bend

    --
    My personal UDP list: 127.0.0.1, 4ax.com, buzzardnews.com, googlegroups.com,
    heapnode.com, localhost, ntli.net, teranews.com, vif.com, x-privat.org

  9. landotter said:

    On Nov 2, 11:32 am, "Leo Lichtman" <[email hidden]>

    Quoted message said:

    "Ken Roberts" wrote: While "tacking" to climb up a steep hill, I found some

    moves different from normal cycling to help me get up the hill easier:
    swinging my shoulders sideways up the hill, and using my arms to "sweep" my
    wheels directly sideways toward down the hill. (clip)
    ^^^^^^^^^^^^^^^^^^^
    I recently saw a guy going up a hill on a scooter doing something like this.
    This was not a normal scooter--it was V shaped, with one front wheel and two
    rear wheels, and he had one foot on each side of the V. He did not touch
    the ground with his feet at all, so the propulsion HAD to come from the way
    he was tacking and throwing his body weight back and forth.

    http://www.razor-scooters.com/trikke-scooters/default.htm



    And some people complain about recumbent trikes taking up too much width
    on the MUP! The riders of the Trikke are taking up about twice the width.

    --
    Tom Sherman - Holstein-Friesland Bovinia
    When did ignorance of biology become a "family value"?

  10. On Nov 3, 7:57 pm, Tom Sherman <[email hidden]>

    Quoted message said:
    landotter said:

    On Nov 2, 11:32 am, "Leo Lichtman" <[email hidden]>

    Quoted message said:

    "Ken Roberts" wrote: While "tacking" to climb up a steep hill, I found some

    Quoted message said:
    Quoted message said:

    moves different from normal cycling to help me get up the hill easier:
    swinging my shoulders sideways up the hill, and using my arms to "sweep" my
    wheels directly sideways toward down the hill. (clip)
    ^^^^^^^^^^^^^^^^^^^
    I recently saw a guy going up a hill on a scooter doing something like this.
    This was not a normal scooter--it was V shaped, with one front wheel and two
    rear wheels, and he had one foot on each side of the V. He did not touch
    the ground with his feet at all, so the propulsion HAD to come from the way
    he was tacking and throwing his body weight back and forth.

    Quoted message said:

    http://www.razor-scooters.com/trikke-scooters/default.htm

    Quoted message said:

    And some people complain about recumbent trikes taking up too much width
    on the MUP! The riders of the Trikke are taking up about twice the width.

    --
    Tom Sherman - Holstein-Friesland Bovinia
    When did ignorance of biology become a "family value"?- Hide quoted text -

    - Show quoted text -

    You realize of course that your statement is simply a variation on the
    classic "I'm not as bad as so and so". Personally, I have no major
    issue with trikes or even those four person pedal carriages they rent
    down at Navy Pier. Some do yield the right of way to others. I just
    wish they all did.

    Regards,
    Bob Hunt

  11. Doc O'Leary wrote

    Quoted message said:

    http://en.wikipedia.org/wiki/Hairpin_bend

    I did not see anything on that page which sounded like what I was doing with
    my bike on those steep climbs.

    "Tacking" is a possible cycling technique even if the road goes perfectly
    straight up the hill. I can steer my bike thru a zig-zag path, even if the
    road does not make any zig-zags. In fact I mostly did tacking moves only
    when the road was _not_ in a curve.

    My understanding is that "switchbacks" are when the road makes zig-zags;
    "tacking" is when me and my bike make zig-zags.

    Ken

  12. Doc O'Leary wrote

    Quoted message said:

    http://en.wikipedia.org/wiki/Hairpin_bend

    I did not see anything on that page which sounded like what I was doing with
    my bike on those steep climbs.

    "Tacking" is a possible cycling technique even if the road goes perfectly
    straight up the hill. I can steer my bike thru a zig-zag path, even if the
    road does not make any zig-zags. In fact I mostly did tacking moves only
    when the road was _not_ in a curve.

    My understanding is that "switchbacks" are when the road makes zig-zags;
    "tacking" is when me and my bike make zig-zags.

    Ken

  13. In article <g9uXi.2249$b%1.1075@trnddc01>,

    Ken Roberts said:

    Doc O'Leary wrote

    Quoted message said:

    http://en.wikipedia.org/wiki/Hairpin_bend

    I did not see anything on that page which sounded like what I was doing with
    my bike on those steep climbs.

    Look again. You went back and forth while moving up a slope. That's a
    switchback.

    Quoted message said:

    My understanding is that "switchbacks" are when the road makes zig-zags;
    "tacking" is when me and my bike make zig-zags.

    Your understanding is wrong. You are mistaking pavement for path. The
    technique is the same regardless of the surface you're on. In fact, it
    could even be necessary to ride switchbacks *on* a switchback road!

    --
    My personal UDP list: 127.0.0.1, 4ax.com, buzzardnews.com, googlegroups.com,
    heapnode.com, localhost, ntli.net, teranews.com, vif.com, x-privat.org

  14. In article <g9uXi.2249$b%1.1075@trnddc01>,

    Ken Roberts said:

    Doc O'Leary wrote

    Quoted message said:

    http://en.wikipedia.org/wiki/Hairpin_bend

    I did not see anything on that page which sounded like what I was doing with
    my bike on those steep climbs.

    Look again. You went back and forth while moving up a slope. That's a
    switchback.

    Quoted message said:

    My understanding is that "switchbacks" are when the road makes zig-zags;
    "tacking" is when me and my bike make zig-zags.

    Your understanding is wrong. You are mistaking pavement for path. The
    technique is the same regardless of the surface you're on. In fact, it
    could even be necessary to ride switchbacks *on* a switchback road!

    --
    My personal UDP list: 127.0.0.1, 4ax.com, buzzardnews.com, googlegroups.com,
    heapnode.com, localhost, ntli.net, teranews.com, vif.com, x-privat.org

  15. Doc O'Leary wrote

    Quoted message said:

    The technique is the same regardless of the surface you're on.

    Maybe that's true for your technique -- but it's not "the same" for mine.

    The two propulsive techniques I described in my original post are much more
    effective for adding net positive propulsive work when performed on a short
    tight turn -- because of (a) Newton's Third Law about reactive force; and
    (b) Force = Mass * Acceleration in a limited distance situation.

    (a) In order for the muscular force and work of accelerating my
    center-of-mass sideways relative to the bicycle wheels not to be _cancelled_
    by the force of decelerating my center-of-mass on the other side, there
    needs to be a change in the direction of the bicycle frame during the time
    between the acceleration and the deceleration. Otherwise the "equal and
    opposite" reactive force from deceleration will slow me and my bike down
    just as much as my acceleration move speed me up. So for a given rolling
    speed, the larger is the radius of curvature (and thus the smaller the
    change in direction), the higher the percentage of the muscular work put
    into my two techiques gets cancelled out -- self-cancelled.

    (b) Since Work = Force * Distance, and the distance I can move my
    center-of-mass sideways is strongly limited, the Work from each move depends
    on the Force, and since Acceleration is proportional to Force in the case,
    that means that getting more Work from each move requires reaching higher
    relative sideways Velocity. Then since the Distance of sideways motion of my
    body relative to the bicycle frame is strongly limited, then the Time
    duration between the start and finish of the sideways move must be much
    briefer. I cannot get the same of work from either of those moves by doing
    the same distance, but slower.

    So if my change of direction is made on a curve with the wider radius of a
    typical road "switchback" or "hairpin", instead of my snappy little
    tight-radius "tacking" turns, there are two cases:
    * If I make one of my special sideways moves slowly so it starts with the
    start of the road curve and finishes with the end of the road curve, then I
    generate little work (according to (b));
    * If I make my move very quickly somewhere in the midst of the road curve,
    then much of its work is self-cancelling (according to (a)).

    Size matters.

    Intelligently controlling my own turns to achieve my own goal works much
    better than having my turns dictated by a road designed for a different
    goal.

    Ken

  16. Doc O'Leary wrote

    Quoted message said:

    The technique is the same regardless of the surface you're on.

    Maybe that's true for your technique -- but it's not "the same" for mine.

    The two propulsive techniques I described in my original post are much more
    effective for adding net positive propulsive work when performed on a short
    tight turn -- because of (a) Newton's Third Law about reactive force; and
    (b) Force = Mass * Acceleration in a limited distance situation.

    (a) In order for the muscular force and work of accelerating my
    center-of-mass sideways relative to the bicycle wheels not to be _cancelled_
    by the force of decelerating my center-of-mass on the other side, there
    needs to be a change in the direction of the bicycle frame during the time
    between the acceleration and the deceleration. Otherwise the "equal and
    opposite" reactive force from deceleration will slow me and my bike down
    just as much as my acceleration move speed me up. So for a given rolling
    speed, the larger is the radius of curvature (and thus the smaller the
    change in direction), the higher the percentage of the muscular work put
    into my two techiques gets cancelled out -- self-cancelled.

    (b) Since Work = Force * Distance, and the distance I can move my
    center-of-mass sideways is strongly limited, the Work from each move depends
    on the Force, and since Acceleration is proportional to Force in the case,
    that means that getting more Work from each move requires reaching higher
    relative sideways Velocity. Then since the Distance of sideways motion of my
    body relative to the bicycle frame is strongly limited, then the Time
    duration between the start and finish of the sideways move must be much
    briefer. I cannot get the same of work from either of those moves by doing
    the same distance, but slower.

    So if my change of direction is made on a curve with the wider radius of a
    typical road "switchback" or "hairpin", instead of my snappy little
    tight-radius "tacking" turns, there are two cases:
    * If I make one of my special sideways moves slowly so it starts with the
    start of the road curve and finishes with the end of the road curve, then I
    generate little work (according to (b));
    * If I make my move very quickly somewhere in the midst of the road curve,
    then much of its work is self-cancelling (according to (a)).

    Size matters.

    Intelligently controlling my own turns to achieve my own goal works much
    better than having my turns dictated by a road designed for a different
    goal.

    Ken

Active in the last 60 minutes

Active in this thread

0 users · 0 guests ·0 bots ·0 total

No signed-in users are active right now.

No known search crawlers active right now.