Winter Drag

On 15/03/12 09:44, Ron Hardin wrote:
The open question for me has always been why I'm so much slower
in the winter than the summer.

Guesses we

1. Air density. It has a huge effect on airplanes - a light plane
that barely clears the wires in the summer is 500 feet above them in
the winter. There's a density cubed sort of effect, I think. A lesser
drag sort of effect could affect bicycles.

2. Viscosity. The grease and idler wheels and so forth grind more
stifly.

(2) is very unlikely. So much energy is involved that it would quickly
heat up any grease, if grease were involved.

3. Energy to stay warm.

(3) is almost certainly the one. If you work harder, you breathe in
more cold air, and the more oxygen you need to replace heat lost to the
air. So it's hard to get much ahead of the curve on this.

Today it was suddenly unusually warm and I find I can sprint up ultra
steep hills on my commute that I had been granny-gearing up for months.

That can't be conditioning difference, and being uphill, the speed is
low enough so that no drag term has much affect.

It has to be heating air, and its necessity in the winter.

I reckon you're possibly right, though I also reckon in winter, the
extra clothing restricts movement and adds weight and wind resistance.

On hot summers days I can't go as fast as in moderate temperatures. I
think my body just refuses to overheat and can't cool fast enough to
allow full output.

--
JS.

The open question for me has always been why I'm so much slower
in the winter than the summer.

Guesses we

1. Air density. It has a huge effect on airplanes - a light plane
that barely clears the wires in the summer is 500 feet above them in
the winter. There's a density cubed sort of effect, I think. A lesser
drag sort of effect could affect bicycles.

2. Viscosity. The grease and idler wheels and so forth grind more
stifly.

(2) is very unlikely. So much energy is involved that it would quickly
heat up any grease, if grease were involved.

3. Energy to stay warm.

(3) is almost certainly the one. If you work harder, you breathe in
more cold air, and the more oxygen you need to replace heat lost to the
air. So it's hard to get much ahead of the curve on this.

Today it was suddenly unusually warm and I find I can sprint up ultra
steep hills on my commute that I had been granny-gearing up for months.

That can't be conditioning difference, and being uphill, the speed is
low enough so that no drag term has much affect.

It has to be heating air, and its necessity in the winter.
--


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

On Wed, 14 Mar 2012 17:44:08 -0500, Ron Hardin
wrote:

The open question for me has always been why I'm so much slower
in the winter than the summer.

Guesses we

1. Air density. It has a huge effect on airplanes - a light plane
that barely clears the wires in the summer is 500 feet above them in
the winter. There's a density cubed sort of effect, I think. A lesser
drag sort of effect could affect bicycles.

2. Viscosity. The grease and idler wheels and so forth grind more
stifly.

(2) is very unlikely. So much energy is involved that it would quickly
heat up any grease, if grease were involved.

3. Energy to stay warm.

(3) is almost certainly the one. If you work harder, you breathe in
more cold air, and the more oxygen you need to replace heat lost to the
air. So it's hard to get much ahead of the curve on this.

Today it was suddenly unusually warm and I find I can sprint up ultra
steep hills on my commute that I had been granny-gearing up for months.

That can't be conditioning difference, and being uphill, the speed is
low enough so that no drag term has much affect.

It has to be heating air, and its necessity in the winter.

Dear Ron,

Time-trial testing for 40 km for temperatures from 62F to 90F (all
below body temperature) showed that power output _dropped_ as ambient
temperature rose, the opposite of what you expect:
http://www.ncbi.nlm.nih.gov/pubmed/21725106

It wasn't much of a drop, either--the riders put out 329 watts at 62F,
but they dropped only 20 watts when the temperature rose to 90F.

***

Tire rolling resistance, on the other hand, rises noticeably as the
temperature drops, meaning that tires roll more reluctantly in cold
weather:
http://www.recumbents.com/MARS/pages...other/Crr.html

The testing showed crr dropping from around 0.0085 to around 0.0045
from around 32F to 80F, but this has little actual effect at the
speeds in question, only about 0.4 mph.

Plug 327 watts and an 8% grade into the calculator below, and you'll
see a ~0.6 km/h difference as crr changes from .0045 to 0.0085:
http://bikecalculator.com/veloMetricNum.html

km/h
for
327w
km/h
up 8% crr

16.07 0.0045
15.99 0.0050
15.91 0.0055
15.75 0.0065
15.60 0.0075
15.45 0.0085

***

Similarly, the density of the air changes about 10% when the
temperature drops from 90F to 40F, but this also has little effect at
10 mph up a steep grade, only about 5 watts at around 330 watts.

Plug 10 mph and an 8% grade into the calculator below, and you'll see
a paltry 5-watt difference in the watts needed for the same speed
between 0F and 100F:

watts
for
10 mph F
up 8% temp

331w 0F
329w 32F
327w 75F
326w 100F

***

Probably the best explanation for a claimed massive improvement in
power on an unexpectedly warm day is the massive placebo effect of
spring on riders freed of winter clothes, winter cold, and winter
winds.

Cheers,

Carl Fogel

lack of exercise
then lack of nutrition
fat buildup
bad air
poor circulation fram all of the above
lack of visual perspective.
lack of imagination for winter sports
and sunlight.
sunlight izza big deal...lookit the plants.

The Ides are aturning point of sorts....the sun rises faster....sap flows...read the news...bang bang bang....

I lived ten years on Pa's Northern Tier at 1400-1800' postcard.
then 20 in Florida. Flroida is healthier by a factor of 1000000000

I bought a van. After garaging my Volvo, riding a bike for 10 years.
Two weeks of van, only two weeks now, began eroding my anerobic with longer warmup times to get the anerobioc working.

I assume winter does this and over and over eventually cycling your body into winter wether you're in Bali or Bangor.

On Mar 14, 4:00 pm, wrote:
On Wed, 14 Mar 2012 17:44:08 -0500, Ron Hardin



wrote:
The open question for me has always been why I'm so much slower
in the winter than the summer.


snip


Probably the best explanation for a claimed massive improvement in
power on an unexpectedly warm day is the massive placebo effect of
spring on riders freed of winter clothes, winter cold, and winter
winds.


The "beautiful day" factor definitely boosts my mojo. Another thing
about the cold is the built-in counter-incentive to go fast from the
discomfort of wind chill.

On Wed, 14 Mar 2012 17:44:08 -0500, Ron Hardin
wrote:

The open question for me has always been why I'm so much slower
in the winter than the summer.

Guesses we

1. Air density. It has a huge effect on airplanes - a light plane
that barely clears the wires in the summer is 500 feet above them in
the winter. There's a density cubed sort of effect, I think. A lesser
drag sort of effect could affect bicycles.

2. Viscosity. The grease and idler wheels and so forth grind more
stifly.

(2) is very unlikely. So much energy is involved that it would quickly
heat up any grease, if grease were involved.

3. Energy to stay warm.

(3) is almost certainly the one. If you work harder, you breathe in
more cold air, and the more oxygen you need to replace heat lost to the
air. So it's hard to get much ahead of the curve on this.

That is likely. I've seen people work in temperatures slightly above
Zero, stripped down to an undershirt and sweating heavily. Which I
would assume meant that a substantial amount of energy must have been
necessary to increase body heat over heat loss in 20 degree air.

I suggest that breathing cold air is probably not a great handicap as
runners have experienced sub-zero conditions with no breathing
problems. Amby Burfoot, editor of Runners world, writes that he ran
in -28 F temperature with no breathing problem.

Today it was suddenly unusually warm and I find I can sprint up ultra
steep hills on my commute that I had been granny-gearing up for months.

That can't be conditioning difference, and being uphill, the speed is
low enough so that no drag term has much affect.

It has to be heating air, and its necessity in the winter.

A little research shows:

Richard Donovan, a runner who was the first to complete marathons at
the South Pole (2002) and North Pole (the last three years). He says
conditions were worse at the South Pole, including -50 temps, strong
winds, and the 9,300-foot altitude. Donovan won the race, but it took
him 8:52, so his lungs had plenty of time to freeze. That never
happened. "I never had any breathing problems at all," he says, "no
burning throat or anything."

A veteran mountaineer Sean Burch joined Donovan at the North Pole
Marathon just 11 months after he had summited Mount Everest. It was
Burch's first marathon, but he won it in 3:43:17. "The North Pole is
heaven compared with Everest, especially Everest in the death zone
[26,000 feet and up]," he says. "Up there, you can barely breathe or
talk. Your throat and lungs burn as if you poured boiling coffee down
them. But I can't say I ever got frozen lungs.

--
Cheers,

John B.

On Wed, 14 Mar 2012 17:00:55 -0600, wrote:

Time-trial testing for 40 km for temperatures from 62F to 90F (all
below body temperature) showed that power output _dropped_ as ambient
temperature rose, the opposite of what you expect:
http://www.ncbi.nlm.nih.gov/pubmed/21725106

But did they do any tests in cold weather? 62F is just barely cool;
I'd expect performance to continue to improve with cooling at least as
far down as 55F.

--
Joy Beeson
joy beeson at comcast dot net

On Wed, 14 Mar 2012 23:21:09 -0500, Joy Beeson
wrote:

On Wed, 14 Mar 2012 17:00:55 -0600, wrote:

Time-trial testing for 40 km for temperatures from 62F to 90F (all
below body temperature) showed that power output _dropped_ as ambient
temperature rose, the opposite of what you expect:
http://www.ncbi.nlm.nih.gov/pubmed/21725106

But did they do any tests in cold weather? 62F is just barely cool;
I'd expect performance to continue to improve with cooling at least as
far down as 55F.

Dear Joy,

Look at the other studies on the right, such as the 100 km test:
http://www.ncbi.nlm.nih.gov/pubmed/20391088

That was 34C/93F versus 10C/50F, with more power again at the colder
temperature.

It would be strange if the gently rising power curve dramatically
reversed itself at some arbitrary ordinary winter cycling temperature.

And it's well-known that you have to supply ventilation for cooling on
stationary bikes to make up for the loss of cooling due to wind.

Overheating is the usual problem in cycling, not shivering.

Cheers,

Carl Fogel

John B. wrote:
Richard Donovan, a runner who was the first to complete marathons at
the South Pole (2002) and North Pole (the last three years). He says
conditions were worse at the South Pole, including -50 temps, strong
winds, and the 9,300-foot altitude. Donovan won the race, but it took
him 8:52, so his lungs had plenty of time to freeze. That never
happened. "I never had any breathing problems at all," he says, "no
burning throat or anything."

A veteran mountaineer Sean Burch joined Donovan at the North Pole
Marathon just 11 months after he had summited Mount Everest. It was
Burch's first marathon, but he won it in 3:43:17. "The North Pole is
heaven compared with Everest, especially Everest in the death zone
[26,000 feet and up]," he says. "Up there, you can barely breathe or
talk. Your throat and lungs burn as if you poured boiling coffee down
them. But I can't say I ever got frozen lungs.

It's not a breathing difficulty but that you have to use the oxygen
intake to produce heat rather than to power muscles, owing to the cooling
of the body core from the very air you're using.

At least that's what's making sense to me.
--


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

On Thu, 15 Mar 2012 08:12:15 -0500, Ron Hardin
wrote:

John B. wrote:
Richard Donovan, a runner who was the first to complete marathons at
the South Pole (2002) and North Pole (the last three years). He says
conditions were worse at the South Pole, including -50 temps, strong
winds, and the 9,300-foot altitude. Donovan won the race, but it took
him 8:52, so his lungs had plenty of time to freeze. That never
happened. "I never had any breathing problems at all," he says, "no
burning throat or anything."

A veteran mountaineer Sean Burch joined Donovan at the North Pole
Marathon just 11 months after he had summited Mount Everest. It was
Burch's first marathon, but he won it in 3:43:17. "The North Pole is
heaven compared with Everest, especially Everest in the death zone
[26,000 feet and up]," he says. "Up there, you can barely breathe or
talk. Your throat and lungs burn as if you poured boiling coffee down
them. But I can't say I ever got frozen lungs.

It's not a breathing difficulty but that you have to use the oxygen
intake to produce heat rather than to power muscles, owing to the cooling
of the body core from the very air you're using.

At least that's what's making sense to me.

But, on the other hand exercise results in an increase in core
temperature. If surface radiation is insufficient to cool adequately
then energy is required to cool the body - sweat, heart rate increase,
and breathlessness.

I suspect that the degree of heat or cold relative to the exertion is
the determining factor, rather then a simple "faster then when cold,
or hot" rule.
--
Cheers,

John B.