Runner versus cyclist - uphill?!

They're equal on a hill negotiable for both, less the weight of
the bicycle; except that fewer people are skilled at the right pacing
and gear selection on a bicycle.

The energy put into the weight of the bicycle is gotten back again
on the downhill side.
--
Ron Hardin
rhha...@mindspring.com

On the internet, nobody knows you're a jerk.

Equal in what way? Speed? Energy output?

In the TdF, you see fans running alongside to top cyclists on the big
climbs, but only for a short distance. On a typical hill, I'd be embarrassed
if a runner passed me. And I'm no racer.

Art Harris

No.... this doesn't equalize on time. Mass on the climb costs time roughly in
proportion to 1/mass. On the descent, roughly, one has :

CdA/2 v^2 = Mg => 1/v ~ sqrt(CdA/Mg)

Consider a test case : I climb 8km @ 16kph, then descend 8km @ 48kph..
Total = 30 minutes + 10 minutes = 40 minutes.

Now I double my mass.

I climb 8km @ 8kph, then descend 8km @ 68kph. Total = 60 minutes + 7.1minutes =
67.1 minutes.

double mass => 67% more time. I don't even count having to corner on the descent,
that one might not be able to take full advantage of the increased terminal
velocity.

Dan

You're comparing apples and oranges.

TDF cyclists are the best of the best on bikes.

The fans who run alongside the cyclists for a stretch:
- Are they also olympic-standard athletes?

Tim.

You're comparing 20 second efforts to 6 hour efforts.

Cyclists are faster uphill. Look at the result of hill runs
to bike hillclimbs on the same hill. The bike wins.

Dan

It doesn't seem that way to me. Cycling is _way_ more efficient than
running. This is the reason it's easy to cycle 30 miles at a 15 mph
average speed, but very, very hard to run even one mile at that average
speed.

Uphill, the difference in efficiency is less. How much less depends on
the gradient of the hill. Yes, at some extreme gradient, a runner will
beat an equally-conditioned cyclist, but it's not going to happen on any
hill you're likely to find paved.

--
Frank Krygowski frkr...@cc.ysu.edu

In my experience it depends on how steep the hill is. Clearly a decent cyclist
who can maintain 10+ mph on a mile long 6% grade will out pace nearly any
runner. As the grade gets steeper the advantage of the bicycle becomes less
and its weight become a bigger factor.

Somewhere over 8%, decent runners start to be comparable to decent riders.

It is my observation that the real advantage of a bicycle is this:

Those muscles which are normally used to carry a runner are used for propulsion
instead.

jon isaacs

As an example, look to the Mt. Washington Hill Climb. The road climbs 4,727 vertical feet in 7.6 miles at an average grade of 12%
The record on a bicycle was set by Tyler Hamilton in 1999 using 39/25 gears and finishing with a time of 50:21, beating his own previous record of 51:56
The foot race record was set by Daniel Kihara in 1996 with a time of 58:21, an even 8 minutes behind the bicycle record.
Other Mt. Washington Auto Road stats are available at http://www.mt-washington.com/autoroad/autofacts.html

Certainly on a somewhat less steep climb the bicyclist has a greater advantage over the runner. I imagine that on a somewhat steeper climb it may be equal, and above that the runner might have the advantage--BUT: this is just educated speculation on my part.

Peace,
Jon Freedner
--
I say, if your knees aren't green by the end of the day,
you ought to seriously re-examine your life -- Calvin

No, the carrying of the runner involves no significant work. The advantage
of the bicycle is an impedance question. A runner has no good way to apply muscle
to get a 20mph running speed, a bicyclist does, for a distance of miles.

It's not the runner's weight that prevents it.

My conclusion: me against a finely trained runner. No
contest; runner wins.

Kolaga Xiuhtecuhtli wrote:

--

Tp

-------- __o
----- -\<. ------ __o
--- ( ) / ( ) ---- -\<.
----------------- ( ) / ( )
---------------------------------------------

Freedom is not free; Free men are not equal; Equal men are not
free.

Which one wins depends on the steepness of the hill. Running is less
energy efficient than cycling, in general. After a certain critical
steepness is reached, the fact that the runner doesn't have to carry
the weight of a bike overcomes running's inherent inefficiency.

Determining the critical steepness angle is left as an exercise for the
reader.

--
terry morse
Palo Alto, CA
http://www.terrymorse.com/bike/

So about a 14% advantage to the cyclist.

The world record marathon (which I assume was run on nearly level
ground) is 2:05:42, say 126 minutes, 12.5 mph

The world hour record (on a UCI bike) is 35mph, about a 280% advantage
for the cyclist.

Certainly a dramatic difference! So i think it is safe to conclude
that at some point the runner will be faster.

Bob

Keep in mind too that near the top, Mt. Washington isn't all that steep,
and the lower part of the road is relatively flat as well (from the main
road to where you really start going up the mountain). A runner would
have more of an advantage (or less of a disadvantage) if you did the
comparison on only the steepest stretch of the road.

The disadvantage a bike has on steep hills is that the added weight slows
you down when climbing. You can test that by running up a hill and then
repeating it after putting on a 20 lb pack.

Bill

--
As an anti-spam measure, my email address is only provided in a GIF
file. Please see <http://home.pacbell.net/zaumen/email.gif>.

Spammers can try mailto:s34...@aol.com mailto:sdkj34...@aol.com

I disagree. The carrying of the runner's weight _does_ involve
significant work, because the weight has to be lifted somewhat (a few
inches or so) and even accelerated upward with each step. The energy
associated with this motion isn't recovered later; it's partly
dissipated as friction, and partly fought against with even more work by
the muscles.

On a bike, the rider's mass stays at the same level. For exactly this
reason, even the original hobby horse (1700s), crude as it was, was more
efficient than running on level ground. It was only much later that
transmission systems were designed to take advantage of the increased
efficiency by providing better impedance matching.

--
Frank Krygowski frkr...@cc.ysu.edu

Rather, I think the difference is the following :

* cycling becomes less efficient at some point due to balance and
traction issues.

* running becomes more efficient uphill, because there is less wasted
effort.

This is just a supposition.

> of very quickly ....

Did *anyone* bring up air resistance, given that the discussion was
about riding uphill?

Anyone who's had to lug a heavy pack uphill knows that the weight is
a significant issue. Balance is an issue only when going so slowly
that you can barely stay on the bike---i.e., when going slower someone
walking at a moderately fast pace. I don't see where traction would be
an issue at all given that it applies equally to both a runner and a
cyclist.

As I said, instead of a supposition, try it out for yourself. If you
compare running with and without the pack, you're mostly seeing the
differences due to the weight.

--

No, the muscles work as springs with respect to weight; think of skipping,
for instance. The energy is recovered immediately and put into another
launch.

You can do jumping-jacks forever too, even though the height would take you up
stairs if redirected and you would tire very quickly if it was, there being
nothing to rebound from.

Yes. Because that is the primary dissipation mechanism in cycling
which isn't mass-proportional. The implication was as the slope
increases, beyond even the 12-15% grades encountered in Mt Washington,
the cycling becomes more mass-proportional.

I don't doubt running is mass-dependent. I never did.

I have been passed by a runner on a hill. This was my regular "commute" hill
on Lehighs' campus, a two-mile climb. In fairness to me, I was just riding up
to my car at the end of a day, and the runner was much younger, and clearly in
very good shape. But still my pride was hurt when she passed me.

--

David L. Johnson

__o | You will say Christ saith this and the apostles say this; but
_`\(,_ | what canst thou say? -- George Fox.
(_)/ (_) |

Didn't think so.

On Sat, 01 Dec 2001 17:30:37 -0600, Kevan <cut...@shreve.net> wrote:

><html><head><title>*</title></head><body><p><font size="7"><b><i>

>This thread should die. It's in incredibly bad taste to mix running and
>cycling together, especially on usenet. The only way this thread could get
>worse is if the triathlon geeks start posting to it. Besides, any serious
>cyclist could smoke any runner up any hill any where any time.
>
>
>--
></i></b></font></p></body></html>
>I have a TINY BOWL in my HEAD
>1 December 2001
>

Not true. Look at any basic A&P text for an explanation of muscle function.

Tim

It it the primary one only at higher speeds. See _Bicycling Science_, page
138 (second edition). For commuting cyclists, air drag and rolling
resistance are about the same at 10 mph (the authors classify cyclists
based on the types of bikes they are likely to use, and assume that
commuters or shoppers use less efficient bikes than racers). The speed
where air resistance and rolling resistance are equal depends on the
type of bicycle you use.

So is cycling, when you are going up a hill steep enough to be
slowed to below approximately 10 mph. BTW, the authors of the book
I cited claim that under ideal circumstances (i.e., an optimal choice
of gears, etc.) you are better off riding a bicycle up a 15 percent
grade than pushing it, although they point out that many bicycles
don't have the right gears for that, Keep in mind that a runner
doesn't have the 20--30 lb weight of the bicycle to carry along either.
Just ask a runner what a difference in 20 to 30 lb would do to how
fast he can go.

Bill

Quite the Troll. Clearly wrong as well but I will avoid pointing out there are
plenty of hills that are too steep for a cyclist to climb.

Nice try but no cigar this time.

Jon Isaacs

I once passed Mark Allen (the triathlete) while he was training for the
Ironman. I was on a bike and he was running. It was a steep little climb, but
I was anaerobic and he had little prestige invested in this event.

The average gradient is misleading as others have pointed ou because a cyclist
goes much faster on the flatter sections.

Constant climb.

jon isaacs

I don't know if I'm buying this... it makes some sense and I'm no
engineer but I think the weight is only one but not the primary
component in a larger picture of the total mechanical advantage of the
bicycle over human powered movement. Aren't the same things working up
as well as down the hill?, so that if the runner was given the
equivelant of the bike's weight at the top of the hill for the
descent, that runner would be able to keep up with the cyclist? I
don't think so.

Can't wait to hear what's really happening here. I used to wonder
about it until I started passing runners(was never running into them
on my routes, I don't think they seek ridiculous hills like we do 8)).
I actually would have thought it was more than the derived 14% figure.

all the best,
-c.porter.

It works differently going downhill: the extra wieght helps speed
you up on a bike. If you are running, you just get more of a load
on your legs because the impact is inelastic. The impact is less
inelastic running uphill because you slow as you move up, so there
is less energy that gets wasted in that. The weight, however, is
a big factor...as I said, try running with and without a 20 lb pack
going up a steep hill, and the difference will be obvious. It is
an easy test to do.

> I said HILL you top posting idjit. I didn't say MOUNTAIN.

Out here in California, Mount Washington would qualify as a hill
(except for the weather). It's only just over 6000 feet high,
after all.

Now, if you try it in winter, you can get into some
fairly serious stuff: like some guys I know who were holed up for
several days in a shelter during a bad storm: they didn't think
it was that serious until one guy stepped outside to take a leak
and had to self-arrest with his ice axe while being blown up hill
by the 80+ mph winds. People gave them up for dead, so when they
finally hiked out, reporters swarmed around them. One reporter
asked if they were praying a lot. Rather than offend anyone,
they said yes, when in reality they were passing the time with
bawdy jokes and songs, or something like that (something you
wouldn't want your mom to read in the papers the next morning).

Do an experiment and see. Jump up and down, as when doing jumping jacks, and
see how long you can do it.

Now rest up, and the next day instead of jumping up and down, jump up stairs
one at a time the same way. The jumping up part is the same (same height) but
you don't come back down.

On your theory, this makes it easier because you don't have to reverse your
momentum. It should in fact be twice as easy on your theory.

Yet there's no comparison. You can do jumping jacks forever, and jump up stairs
for only a short time.

That proves that there's a rebound effect and it's highly efficient.

Just because a cyclist cannot climb it does not mean a runner cannot run it.

Even a crappie runner like me can run up hills I cannot climb on any bicycle.

jon isaacs

Not true. Again, start with the basics. Thought experiments are an infamous
way to go wrong. Come on, try reading just a little, you might like it!

Tim

C'mon, Jon... you're being modest.

While just the other day, Mark and I were talking about the high
points in our lives...

"... and then there was the day I almost nipped Jon Isaacs up this
sharp little hill. Oh, and the wins at that Hawaii thing...."

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

You can also notice your breathing rate (finally the gauge of how hard you're
working at the moment) is considerably different for jumping jacks and jumping
stairs, even though the height of the jumps is the same.

And breathing rate is negligible for slow running even though there you are, going
up and down, and you'd predict pretty heavy going from your misunderstood textbook.

> Well, you're in California, and everybody knows what THAT means. Here in REAL
> America, 6,000' is more than enough to be a mountain. Hell, where I live, they
> call 300' hills mountains.

The other issue is that you can't judge a mountain strictly by summit elevation. Isn't pancake-flat Kansas at an elevation of 5000 feet or something like that? A small pile of dirt in Kansas is _not_ a 5,000 ft mountain. The Presidential Range in NH rises over 5,000 feet above the surrounding valleys and river systems.

Sure, California has 14,000 footers and nobody is going to dispute that they are really big mountains, but how many vertical feet do you have to climb from base to summit? Certainly not 14,000.... Even Mt. Everest in the Himalayas has "only" a 10,000 foot climb from base to summit. Admittedly, the base is at 19,000 feet.

My point is that Washington and other rugged northeastern mountains have substantial climbs to the summit, very steep and rugged trails, present severe exposure risks and all of the other dangers of a mountain environment (and in some cases those of an alpine environment, depending on where you are and when), and they _need_ to be respected as serious mountains. About the only thing that people on Washington don't have to worry about is AMS and other altitude induced illnesses. Too many people have underestimated eastern mountains and have gotten hurt or killed as a result, so please try not to propagate this "it's only a hill" view if you haven't been in the whites and don't know the environment and its risks.

Peace,
Jon Freedner
avid cyclist
certified wilderness first responder
volunteer search and rescue team member

It was a true story which I meant to be funny.

However I believe your response was about the funniest thing I have read for a
while.

Thanks for the laugh.

jon isaacs

The highest point in Kansas is 4039 feet above sea level, the lowest is 680. >

Actually Death Valley is less than 100 miles as the crow flies from Mt.
Whitney, This vertical distance is more than 14000 feet.

And at the actual base it is around 3000 feet I believe so that makes
significantly over 10,000 feet.

There is not doubt that such mountains are formible. Of course the altitude
thing is important, especially in Colorado where climbs can take you to 11,000
feet or more. A 5000 foot climb is a whole different thing when you start at
6000 feet.

jon isaacs

Lone Pine is about 3000ft. Most people begin their hike at the Portal
which is @8000 feet. I did this in one day last summer- brutal isn't
a strong enough word.

Which runner or cyclist? the same person? How heavy is the bike and or
rider?

The better question is:

How steep does a hill have to be before the same person can run up faster
than he/she can bike?

It seems to me that at about the same degree of steepness, both a runner and
cyclist have to start walking, so it is really a moot point, unless you are
talking about a theoretical hill of continuous steepness past the point
where a cyclist is now just a walker pushing a bike uphill.

In the real world, there aren't paved hills that very cyclists have to walk,
so unless you want to ask questions about off road, fat slobs or heavy
bikes, etc. the practical answer is cycling wins because it is markedly more
efficient than jogging.

Segway to your second comment - A road bicycle ridden below about 15MPH is
the most efficient mode of propulsion on the planet, human, animal, or
machine powered.

"Kolaga Xiuhtecuhtli" <XXXiuht...@worldnet.att.net> wrote in message
news:3C08A9F2...@worldnet.att.net...

I think there are clearly hills that are faster to run up than to climb. Your
belief that cyclists and runners have to start walking at the same point is
highly dependent on the runner. Somewhere between 10 and 20 per cent
gradient, I think the cyclist has slowed to a pace where he/she ought to
getting off and dropping the bike would be faster.

Your contention that a runner has to start walking is bogus. Stairs are
clearly steeper than 20% and can be run.

I imagine you have never been around strong runners or some such thing.

jon isaacs

> Kevan wrote:

I've hiked up Mount Washington and the steep part of the trail (anything
one would call being on a mountain) took at most a few hours. I've
also been up Cannon Mountain (via the steep face you can see from the
road, as opposed to a trail).

If you pick the 'surrounding valleys' as the base, and take Mount Whitney,
you are talking about nearly 10,000 feet elevation gain. If you go
from Yosemite Valley to the top of Half Dome, it is about 5000 feet in
elevation gain (a bit more, actually). Of course, people generally drive
to a trail head for Mount Whitney, in which case the elevation gain is
less (although most parties take two days to get up it).

Oh, and don't forget the effects of the altitude on your performance, if
you haven't aclimatized.

Odd that you snipped the part I put in mentioning winter weather, but in
any case, those trails are hardly steep and rugged: it's just walking,
after all.

This claim is only true on level ground, or on grades that are not all
that steep.

Well, if you take a 150 lb cyclist and a 22.5 lb bike (which adds 15%
to the weight), and it would take a cyclist an hour to ride up a
steep hill with a zero-mass bicycle, going slow enough that air resistance
is not significant, then the cyclist would take 1 hour and 9 minutes
with the 22.5 lb bike. That extra 9 minutes (which adds 15 percent to
the total time) is for ideal conditions where all the extra work goes
into moving the bike up the hill.

It's obvious that the mass of the bicycle is a significant factor. If
you want to test that on your on bike, put on some panniers or carry
a pack along, and time how long it takes to ride up a hill with and
without an extra 20 lb.

It can't work differntly. The only thing that is changing is the
slope.

Does weight matter? sure. Adding weight to the runner or the cyclist
has a predictable effect on the duration of the hill climb for that
individial. Varying the weight of the bicycle, we can determine a
point where running and cycling are the same for that individual. But
the reason why a cyclist climbs a hill faster than a runner is because
the bicycle converts work into distance better than running, and that
includes the weight of the bicycle. We wouldn't be talking about this
if the standard bike hadn't progressed to the point where we could
effectively climb hills with them. This is inherent in the design.

I climbed some hills today, actually a route I last did on 9-10, with
about 8 lbs more than when I climbed them during peak season(at least
one or two being four layers of clothing 8)).

bcnu-c.porter.

I'm not sure about grade limitation. What if for experiments sake, the
bike has some really large cogs on the cassette? We're not exactly
talking about the grade where the cyclist has the bike slung over the
back reaching for the next handhold.

I wonder if this has been done in a labratory simulation. At the other
end of the spectrum, the steepest downslope, freefall, I beleive the
mechanical advantage of the bike is reduced to 0.

bcnu-
c.porter.

> On Mon, 03 Dec 2001 01:05:18 GMT, nob...@nospam.pacbell.net (Bill Zaumen) from

> I didn't write anything that was in this message. Please attribute more
> carefully.
>

What the hell are you talking about? All it shows is that some guy
calling himself free...@main.rr.com posted a response that included
something you apparently wrote. Who said what is clearly indicated
by the number of '>' symbols starting each line.

In fact, the phrase "Kevan wrote:" was provided by
free...@main.rr.com, so he was being quoted, not you.

Well, it does: the slope makes things work differently. You can coast
downhill. Try that going uphill and see how well you stay on the bike
once you start rolling backwards. For a runner there is even more of a
difference. If you don't think there is a difference, buy a copy of
the book _Bicycling Science_ and look at a few of the graphs.

We wouldn't be talking about this if you knew basic physics. The
runner doesn't have to waste energy moving a 20+ lb bike up the hill
with him. The cyclist does. The question is simply whether the
inefficiency caused by the weight of a bike slows the cyclist down
enough to remove the advantage due to the bicycle's design. Meanwhile,
a runner will lose less energy running uphill due to landing on his
shoes after each step than he would going downhill or on a level surface
(try all combinations and you will see that the impact you feel on your
heels or your knees will be less).

How large a cog do you want to put on there?? How about a 20 front 34 back?

But anyone who has tried to climb what I term "limiting hills" on a bicycle
finds that it is a problem of balancing the front and rear traction all while
avoiding a wheelie.

Normally on a very steep hill the problem is keeping the front wheel on the
ground. This requires getting ones weight as far forward as possible. Ones
butt has to off the seat and upper body nearly resting on the handle bars.
This is an awkward position but it is the only way to keep the front end down.
Standing does not work on such steep climbs. This position also greatly
reduces ones efficiency.

_______________________________

Some people here seem to consider this discussion is limited to paved
conditions.

Personally I don't view this as a limitation in this discussion. This is
because I view hills as hills and the steepest hills I know of are off road.

But I believe in San Francisco there are some paved hills that are over 30% and
Jobst has mentioned climbs in the high 20's.

Last year there was a discussion of some sort and i ended up measuring a hill
that I like. The do-able part was about 32%, the barely do-able was 38%. I
believe I could run up this hill significantly faster than I can ride it.

And I am much better rider than i am a runner.

And for most riders, there are runners that can out do them on a moderately
steep grade.

jon isaacs

Danny

"Bill Zaumen" <nob...@nospam.pacbell.net> wrote in message
news:nobody-0212...@adsl-209-233-20-69.dsl.snfc21.pacbell.net...

A runner can't 'dig in' on asphault, and just ask any runner how well
he'd do if he was 20 lb overweight. I assumed we were comparing both
on similar surfaces.

BTW, the 'low friction' is a myth. The rubber surface of bicycle tires
is going to have about the same amount of friction as running shoes,
and possibly more (for cornering---to allow tighter turns).

The advantage the runner has is that all his weight is on the foot doing the
work. The runner also does not half to worry about flipping over with an
unwanted wheelie.

My guess is that anyone who thinks that a bicyclist will be faster up ALL hills
has never ridden up a hill with alongside a good distance runner..

Jon Isaacs

Bill is responding to a contention which was never made.

The assertion is that weight alone is not the only reason a runner
has an advantage. Bill's response is "of course weight matters to a runner".
Nobody questions that. The question is whether a runner, with the additional
weight, would still be able to beat the cyclist up the same hill.

It obviously comes down to what someone else called "an impedence match".
To ignore that is to be "too focussed on the weight".

Dan

\R

I would still guess that there are probably climbs in which the bicycle
loses it's advantage.
Burke mountain in Vermont, maybe ? though I don't know if there are any
organized races up that one.

\R

Jonathon Freedner wrote;

"As an example, look to the Mt. Washington Hill Climb. The road climbs
4,727 vertical feet in 7.6 miles at an average grade of 12%
The record on a bicycle was set by Tyler Hamilton in 1999 using 39/25 gears
and finishing with a time of 50:21, beating his own previous record of 51:56

The foot race record was set by Daniel Kihara in 1996 with a time of 58:21,
an even 8 minutes behind the bicycle record."

Thanks,

\R

\R

>

\R

> Cyclists are faster uphill. Look at the result of hill runs
> to bike hillclimbs on the same hill. The bike wins.

The Apple Computer Cycling Club used to have a timed hillclimb of
Old La Honda twice a year. One year, they also timed runners.

There was one fellow who usually beat everyone on his bike, except for
Cat 1s and pros. He was also a runner. His time up OLH on foot
was several minutes slower than on bike (he still beat all the other
runenrs).

I don't remember the actual times, or much else, actually.

--
Stella Hackell ste...@ncal.verio.com

She who succeeds in gaining the mastery of the bicycle will gain the
mastery of life.
--Frances E. Willard, _How I Learned to Ride the Bicycle_

All this data was collected just last month for a science fair
project. Two of the hills were those used in the San Francisco Grand
Prix.

Taylor St Fillmore St. 22nd St.
Greenwich-Union Vallejo-Broadway Church-Vicksburg
21% 24% 32%

Bike 18.7s, 510w 21.6s, 520w 32.2s, 410w
Run 27.3s, 310w 27.6s, 360w 31.1s, 370w

Best time of five runs. Average power was computed from

power (w) = 9.8 * rise (m) * mass (kg) / time (s)

What's excellent about this experiment is that it was the same 12-year
old athlete, running and biking. As you can see, the steeper the
hill, the less difference there is between running and cycling.

This data is sprint-oriented. Climbing below lactate threshold would
probably tell a different story.

Notes:

1. Hill lengths varied slightly, but this was taken into account for
the wattage calcs. Length of hill was measured with a 100 foot tape.
All three hills were between 265 and 285 feet.

2. Gradients used to compute elevation rise were determined by
measuring the hill at the top, middle, and bottom. Measurement was
done with a string level and tape measure over an approximate 20 foot
run. These agreed with 1% with data published by the SF City
Engineer's office.

3. 34f/25r gearing was too high for smooth sprinting on Church St.
Hill. This probably accounts for the power dropoff from ~500 watts to
~400 watts. Biking time could probably have been improved with lower
gearing.

4. Weight of runner, 105 lbs. Weight of runner plus bike 125 lbs.

5. The reason that the running time up Church St. was lower than the
cycling time, yet the power was also less, is due to the weight of the
bike.

Those powers seem pretty high for a 103-lb 12-year-old.....
But also the average grades seem a bit high.

Where did you get the data?

Dan

I provided a simple calculation in a previous message showing that
a 22.5 lb bike would slow a 150 lb cyclist by 15 percent on a hill
steep enough that what limits the cyclist's speed is the steepness
of the hill (i.e., air resistance and rolling resistance are
negligible). The one piece of data anyone produced---the time
difference between a cyclist and a runner going up Mt.
Washington---were, as I recall, within 15 percent of each other.

And that comparison included relatively flat stetches, particularly near
the bottom of the peak.

Old La Honda Road flattens out for the 1/2 mile or so (at most a mile)
from the top, although you still are climbing. I'd bet it would be
closer, ar maybe faster running, if he tried it only on the steepest
section of the road. Old La Honda Road isn't all that steep compared
to some other roads in the area (e.g., Page Mill Rd.).

And when perfectly balanced ...

Of course, a reasonable test would only consider terrain that is low
enough angle to ride a bike without having extreme problems in staying
balanced on it to avoid the problems that Reg mentioned. Otherwise,
we can simply make the slope 50 or 60 degrees, give the "runner" some
climbing shoes, and let him take as much time as he wants.

And if he weighed 230 and got up in the same number of seconds, it
would be twice the wattage. One thing to bear in mind, this was a
100+ RPM high intensity, short duration sprint. The SF GP racers were
taking more like 30-35 seconds to get up these hills--a much better
strategy in a 6-hour race!

As mentioned, the grade was measured with string level and tape at
three different points on the hill, each over a 20-foot run. Also used
a sailboat inclinometer mounted on a 2 meter pole, which agreed within
1%. Finally, for two of the hills there is corroboration from a SF
travel site citing the City Bureau of Engineering:

1. & 2. Filbert between Leavenworth and Hyde; 22nd Street between
Church and Vicksburg, both 31.5 percent gradient.
3. Jones between Union and Filbert, 29 percent.
4. Duboce between Buena Vista and Alpine, 27.9 percent.
5. & 6. Jones between Green and Union; Webster between Vallejo and
Broadway, both 26 percent.
7. & 8. Duboce between Divisadero and Alpine; Duboce between Castro
and Divisadero, both 25 percent.
9. Jones between Pine and California, 24.8 percent.
10. Fillmore between Vallejo and Broadway, 24 percent.

- Pete

At 20% grades a bike would be less efficient whatever its gearing, the
authors claim.

So the 12 year old was faster than George Hincapie up the hill,
even if it was just for one ascent compared to part of a 6-hour
effort....

I still find that rather remarkable.

An absolutely key element in this discussion in W&W is the relative
efficiency versus gradient of walking and pedaling. It isn't
just weight. Which is what I've been maintaining all along, which
Bill Zauman doesn't understand. Either that, or he's just being
argumentative.

This is only a limit. Runners can run up such a hill rather easily but a
cyclist is clearly in trouble for multiple reasons.

It is true that any hill a cyclist can ride up faster than someone can run it,
a cyclist will beat a runner. <g>

But somewhere between Mt. Washington at 14% and a limiting climb at about 38%,
I think one will find that runners are faster.

jon isaacs

\R

I suppose how you define 'efficient' is important. It's clearly not
_faster_ to run up the hills, even at hills much greater than 20%.

From my previous post:

Are we talking about biomechanically efficient or physiologically
efficient? Actually the answer is that biking always rules, unless
you're overgeared, in which case running and out of saddle pedaling
become nearly the same excercise.

I have to say that actually conducting an experiment changed the way I
had always looked at this. Get off the sofa (or trainer) and try it
yourselves!!!

- Pete

I don't know about runners, but I blew past a rollerblading person the other
day, and boy, was she pissed!

Pat
:

> TJTalbert wrote:
> >
> > >No, the muscles work as springs
> >
> > Not true. Look at any basic A&P text for an explanation of muscle
> > function.
>
> Do an experiment and see. Jump up and down, as when doing jumping
> jacks, and see how long you can do it.
>
> Now rest up, and the next day instead of jumping up and down, jump up
> stairs one at a time the same way. The jumping up part is the same
> (same height) but you don't come back down.

Do some experiments and see:
Jump up and down, like a kangaroo, on flat terrain and see how far you
can travel. Try a mile.
Skip rope for an hour.
Run in place for an hour.

> Yet there's no comparison. You can do jumping jacks forever, and
> jump up stairs for only a short time.

You _can't_ do jumping jacks forever, and furthermore the above
movements are more analogous to the activity involved in running anyway.

> That proves that there's a rebound effect and it's highly efficient.

The rebound effect is partially inefficient, and depends on a certain
range of parameters, which is why at some speeds it's easier to walk or
cycle than to run and vice versa. Steepness of grade is one such
parameter that is the topic of discussion on this thread.

Van

--
Van Bagnol / v a n at wco dot com / c r l at bagnol dot com
...enjoys - Theatre / Windsurfing / Skydiving / Mountain Biking
...feels - "Parang lumalakad ako sa loob ng paniginip"
...thinks - "An Error is Not a Mistake ... Unless You Refuse to Correct It"

> It is my observation that the real advantage of a bicycle is this:
>
> Those muscles which are normally used to carry a runner are used for
> propulsion instead.

Yes, bicycling decouples muscle involvement used for propulsion from
muscle involvement (if any) used for maintaining momentum. Skate boards,
scooters, rollerblades, and ice skates serve a similar function.

Runners, by contrast, must continue running to keep going forward.
(Substitute "bipedal locomotion" for the technically prissy.)

> Harris wrote:
>
> > In the TdF, you see fans running alongside to top cyclists on the
> > big climbs, but only for a short distance. On a typical hill, I'd
> > be embarrassed if a runner passed me. And I'm no racer.
>
> I have been passed by a runner on a hill. This was my regular
> "commute" hill on Lehighs' campus, a two-mile climb. In fairness to
> me, I was just riding up to my car at the end of a day, and the
> runner was much younger, and clearly in very good shape. But still my
> pride was hurt when she passed me.

Oh, come off it, Dave. You just wanted a better view of the clearly very
good shape. :-)

Hell, why not go to the extreme? Make it a vertical climb, outfit the
"runner" with a bag of chalk, and the "cyclist" with a crank-type
rope-climbing thingie. RH could do jumping jacks forever till he gets
somewhere. :-)

Well, muscles do not act as springs. Muscles have filaments that slide past
each other. Muscles only deliver power on contraction and this is why muscles
are found in pairs - one for extension and one for flexion. The kangaroo is an
interesting situation - its legs do act as springs (not muscles) when it is
leaping allowing kangaroos to travel at high speeds at a surprisingly low
energy expenditure.

Muscles do indeed act as springs. Highly damped springs, but springs
nonetheless. Try a vertical jump from a static crouch, and measure how
high you can get. Now try the same vertical jump, this time instead
starting with a small "pre-jump". Notice which method produces a higher
jump. Why?

--
terry morse
Palo Alto, CA
http://www.terrymorse.com/bike/

You probably startled her so suddenly that her CD player skipped a
track. :-)

Well, what Whitt and Wilson claim is that for lower power outputs, around
.1hp, it's faster to walk than to cycle up grades greater than 20%. At
grades of 15% to 20% they say that it's close, but that the bike will be
better only if its drivetrain is average or better and if its gears are
proper.

I'd assume they think their findings would hold for somewhat greater power
outputs.

It's not obvious your data are inconsistent with their claims. Perhaps
biking permitted higher power outputs than could be had by running. But if
your data are inconsistent with W and W, I'm not sure what to say. I would
want to read about some more controlled experiments, I suppose.

> Ron Hardin wrote:

> > No, the carrying of the runner involves no significant work. The
> > advantage of the bicycle is an impedance question. A runner has no
> > good way to apply muscle to get a 20mph running speed, a bicyclist
> > does, for a distance of miles.

Humans have been able to attain 20 mph (about 100 yd dash in 10.2
seconds).

Let's try this: Run downhill at 20 mph for a distance of miles. No need
to apply as much muscle to get to speed now. See if you are tired, and
wonder why.

> > It's not the runner's weight that prevents it.

Run with a 30 lb pack. See if it involves no significant work.

> I disagree. The carrying of the runner's weight _does_ involve
> significant work, because the weight has to be lifted somewhat (a few
> inches or so) and even accelerated upward with each step. The energy
> associated with this motion isn't recovered later; it's partly
> dissipated as friction, and partly fought against with even more work by
> the muscles.

It's partially recovered, which is why it's easier to run with running
shoes than with leather-soled sandals. They key is that it's only a
partial recovery, and even then, the elastic properties of muscle are
due to actin-myocin tension in the muscle fibers which _does_ require
some energy, albeit brief.

> On a bike, the rider's mass stays at the same level. For exactly this
> reason, even the original hobby horse (1700s), crude as it was, was more
> efficient than running on level ground. It was only much later that
> transmission systems were designed to take advantage of the increased
> efficiency by providing better impedance matching.

It's also evident in skateboards, scooters, and shopping carts.

?? That's not how I read it.

In the second edition of their book, p. 183, they make a stab at
calculating this. They're talking about pushing the bike uphill versus
pedaling slowly, both at 1.5 mph. It's obviously a rough calculation,
with many assumptions that, at best, could be debated. But the
conclusion of one paragraph says "From the estimations above, it appears
that it is easier to ride up a 15-percent gradient than to walk at the
same speed of 1.5 mph pushing the bicycle by about ... 30 percent."

Then they point out that gearing may not be low enough to pedal 1.5 mph,
and based on that (in a further paragraph) "... the percent difference
quoted above should be taken as about 18 percent." [Still in favor of
pedaling.] "This difference gives only a small margin for the extra
transmission friction involved in the use of a very low gear.
Calculation along the lines of the above show that the 15-percent
gradient may be a critical one, and that at gradients of 20 percent
there is not really appreciable advantage in riding the bicycle, even in
a low gear."

My comments on this: of course, they're walking a bike uphill, so the
weight is the same for rider and walker. Still, it seems to validate
what we've generally been saying - biking is more efficient up to some
certain grade. They don't really mention whether the drivetrain is
"average or better", as far as I can see, but they seem to be saying
it's possible for "extra transmission friction" to eat up 18% of your
power - that is, it may be only 82% efficient!

W & W don't specify what type of transmission they're discussing. A
five-speed Sturmey-Archer internal gear is not very efficient in low
gear, IIRC. Would it be as bad as 82%? But I believe a granny-geared
derailleur bike is quite efficient in the lowest gear. On my bikes, at
least, the chain runs quite straight in low gear (as opposed to being
deflected sideways) and I believe the chain entering or leaving a
sprocket at an angle is one of the things that decrease efficiency. I'd
expect any decent derailleur bike to be well over 90% efficient in low
gear.

For reference, they say (graph, figure 7.2) that 0.1 HP is about 15 mph
on a bike.

--
Frank Krygowski frkr...@cc.ysu.edu

They were also talking about *pushing* the bike up hill. Depending
on your weight and the wieght of the bike, you could easily have a
15% penalty for pushing the bike up rather than walking or running
with no bike at all.

I picked 50 to 60 degrees because one guy supposedly tried to impress
his friends by climbing up a route on the Glacier Point Apron in
Yosemite (a slab about that steep) wearing roller skates. I presume
he had a top rope, but who knows :-).

At least it is an angle that you can get up on something that rolls!

BIll

Read what they said: they were comparing cycling versus walking while
pushing the bike. I showed that you can expect around a 15% penalty
in time (assuming constant power output) in pushing a bike versus
walking without one when you are limited primarily by the steepness.

If you look at the data people provided in actual measurements for
someone running versus cycling up a hill (same person in each case),
it was closer than 15%.

Bill

I have the second edition, too.

Whitt and Wilson begin their discussion by assuming what they take to be a
typical power output: .1 hp. (That's 'point 1' in case the period isn't
clearly visible). (See p. 182.) They say then that at a 15% grade this
power will yield a cycling speed of 1.5 mph (one point five). So, they're
beginning with an assumption about power output and then inferring speed.

Yes, that's right. They started with a cyclist putting out a certain amount
of power, .1hp, and then found he would go 1.5 mph. Then they compare a
runner going at the same speed.

They conclude that the walker pushing a bike will have an easier time of it
at s>20%. That implies for a constant metabolic power output the walker
plus bike will go faster on these grades, which is how I reported the
matter. What I said is equivalent to what Whitt and Wilson are saying.

No, they don't say that the gearing on a typical bike is too low to pedal
1.5 mph. They say that pedal that slowly, 1.5 mph, with a gear of about 20"
the cadence is "suboptimal". (See p. 183). That makes the bike less
efficient than it would be if it had optimal gearing. Since they then use
this reduced efficiency in their continued calculations, they are assuming a
cyclist _is_ pedaling at 1.5 mph with this more typical but suboptimal gear
size.

On the 15% grade, the walker's muscle efficiency is 12.3 % and the cyclists
with optimal gears is 17.5%. So the walker's efficiency is about .7 of the
cyclists. That's what Whitt and Wilson are saying on p. 183. Then, they
say, if we consider the bicyclist with more realistic and suboptimal gears,
the 20" gear, the walker's efficiency rises to .82 of the cyclists. That
means the cyclist's muscle efficiency is 15% with the typical suboptimal
gears. (12.3/.82)

That means that the cyclist can afford to lose less than _3%_ of his muscle
energy to the transmission and still stay ahead of the walker-- _not_ 18%,
as you say below.

Losing 3% more than typical power to a transmission can happen on a badly
maintained chain and sprocket set up.

I summarized this result by saying that on grades between 15 and 20% the
cyclist would be more efficient than the walker only if the drive train were
maintained to an average or better degree. By "proper" gearing I meant the
20" they assume for a granny gear (although "proper" in this case is
suboptimal. See above.)

Yes, W & W are talking about pushing a bike, as I said in my first post.

If the runner _doesn't_ push the bike, and just runs, things are worse still
for cyclist's relative efficiency.

I have the second edition, too.

>

Yes, that's right. They started with a cyclist putting out a certain amount

It's obviously a rough calculation,

No, they don't say that the gearing on a typical bike is too low to pedal

> on a bike.
>
>
> --
> Frank Krygowski frkr...@cc.ysu.edu

For the last umpteen postings by various people, that was being ignored,
so it is important to state whether there is a bike being pushed or not.

On the internet, nobody knows you're a jerk.

The disadvantages which come from a bike at steep slopes, relative
to an "idealized" runner, are :

* weight -- extra weight from the bike
* available gearing
* balance
* rider position
* traction

Real runners also face the last 3 issues, so the key is the grade-dependence
for each mode on a given surface.

"Available gearing" isn't really the issue here, as one can always go to
lower gearing (tire rolling circumference * front ring / rear cog)

For example, at my best on a 7% grade I use a 39/21.
With an "effective grade" of 1, on a vertical wall (I use a
modified definition of grade : sine instead of tangent),
I would want a 39/300. I'll have a hard time finding that.....
Maybe a 20/30 with "140c" wheels :).

Dan

I think it is relevent to ask if anyone actually believes that it is possible
on any normally available bicycle to actually climb a 15% grade at 1.5 mph???
If you have only 0.1 hp available, you will be walking up a 15% grade no matter
what gears you have.

I also point out that this article seems to be discussing pushing a bike up a
hill vs riding it.

As others have pointed, this is quite different than running up a hill.

Consider this example:

Compare the gradient of normal stairs. These are something that every one of
us can run right up and do so for several floors if necessary. No way on a
bicycle to climb an equivelent gradient.

jon isaacs