Does Colder Weather = Slower Biking, and if so, why?

[Colorado Bicycler]

It seems to me that when I bike at about 40F or colder on my mtn bike
with 1.75 slicks, everything slows way down, including me!

So, is it psychological, physical, the tires, the lubricant, SAD, or am
I just imagining things.

[Ron Hardin]

Colorado Bicycler wrote:
>
> It seems to me that when I bike at about 40F or colder on my mtn bike
> with 1.75 slicks, everything slows way down, including me!
>
> So, is it psychological, physical, the tires, the lubricant, SAD, or am
> I just imagining things.

1. Denser air

2. You have to heat all the air you breathe to body temperature.
The harder you work, the more air you have to heat as you breathe more.
So you reach a calorie limit that's self-reenforcing pretty fast.

--
Ron Hardin


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

[Ken M]

Ron Hardin wrote:
> Colorado Bicycler wrote:
>
>>It seems to me that when I bike at about 40F or colder on my mtn bike
>>with 1.75 slicks, everything slows way down, including me!
>>
>>So, is it psychological, physical, the tires, the lubricant, SAD, or am
>>I just imagining things.
>
>
> 1. Denser air
>
How much denser is it at 40 degrees vs 70 degrees?
And how much would such a change slow a rider down?

> 2. You have to heat all the air you breathe to body temperature.
> The harder you work, the more air you have to heat as you breathe more.
> So you reach a calorie limit that's self-reenforcing pretty fast.
>
So your saying that it would be even tougher to ride at 20 degrees vs 40
because your body has to heat the air even more?

Ken
--
On the internet, nobody knows you're a jerk - unless you act like a jerk
on the internet too. - Quote modified by Ken M.

[Colorado Bicycler]

http://www.xenodochy.org/ex/abstract/mileage.html

This website estimates a 6% drop in car mileage from a 30 degreeF drop
in temperature.

Anyone else have some figures relating air density to temperature
change, and its effect on bicycling?

[Ken M]

Colorado Bicycler wrote:
> http://www.xenodochy.org/ex/abstract/mileage.html
>
> This website estimates a 6% drop in car mileage from a 30 degreeF drop
> in temperature.
>
> Anyone else have some figures relating air density to temperature
> change, and its effect on bicycling?
>
I was curious about this and did a bit of surfing and found
this:http://www.icebike.org/Articles/SlowerWinter.htm

Some interesting theories.

Ken
--
On the internet, nobody knows you're a jerk - unless you act like a jerk
on the internet too. - Quote modified by Ken M.

[Colorado Bicycler]

Thanks for the input.

But, even going down familiar hills, where I am not pedaling, the whole
thing goes slower! I know this because I keep pretty good track of my
coasting downhill speeds.

[Colorado Bicycler]

Ken, thanks for the icebiker site. I should have gone to this right
away.

Somewhere, a similar post has gotten lost, so this post may end up
being a repeat!

[Colorado Bicycler]

Thanks - I should have known to look at the icebike site first, as I
often refer others to that site. Appreciate greatly your web search.

I know, I worked really hard today!

[[email protected]]

Check out analytical cycling
http://www.analyticcycling.com/ForcesPower_Page.html
The air density increases by about 0.1 kg/m3 going from 60F to 20F and
they say this demands an increase in power from about 275 watts to 285
watts given all the same other parameters. That is only a 3.6%
increase in power needed.

Ted

[[email protected]]

Colorado Bicycler > wrote:

> So, is it psychological, physical, the tires, the lubricant, SAD, or am
> I just imagining things.

Dunno about you, but I slowed WAY down this morning when I realized how
much black ice there was out there.


Bill

--------------------------------------------------------------
| They that can give up essential liberty to obtain a little |
| temporary safety deserve neither liberty nor safety. |
| --Benjamin Franklin |
--------------------------------------------------------------

[mort]

Colorado Bicycler wrote:
> It seems to me that when I bike at about 40F or colder on my mtn bike
> with 1.75 slicks, everything slows way down, including me!
>
> So, is it psychological, physical, the tires, the lubricant, SAD, or am
> I just imagining things.

Here's a chart of air temperature vs. density.

http://www.ce.utexas.edu/prof/kinnas/319LAB/Book/CH1/PROPS/densgif.html

I think that the effect is greater than posited by Analytic Cycling.
It also seems to make sense that heating the body would take away some
of the energy normally used to power muscles, although that may not be
how it works at all. I certainly eat more after winter rides than I do
in the summer.

Mort

[Colorado Bicycler]

No ice (white or black) today!

[Rich]

mort wrote:
> Colorado Bicycler wrote:
>
>>It seems to me that when I bike at about 40F or colder on my mtn bike
>>with 1.75 slicks, everything slows way down, including me!
>>
>>So, is it psychological, physical, the tires, the lubricant, SAD, or am
>>I just imagining things.
>
>
> Here's a chart of air temperature vs. density.
>
> http://www.ce.utexas.edu/prof/kinnas/319LAB/Book/CH1/PROPS/densgif.html
>
> I think that the effect is greater than posited by Analytic Cycling.

I think the effect is probably no where near as large as the increase in
resistance due to cold lubricants.

Rich

[jkinney2]

IMHO, it is all the clothes you have to layer up in. Be that as it may I do
notice a slow down the colder it gets. Well the extra clothes and the wind
driven chill factor.

Jim


"Colorado Bicycler" > wrote in message
ups.com...
> It seems to me that when I bike at about 40F or colder on my mtn bike
> with 1.75 slicks, everything slows way down, including me!
>
> So, is it psychological, physical, the tires, the lubricant, SAD, or am
> I just imagining things.
>

[Mark Hickey]

"Colorado Bicycler" > wrote:

>http://www.xenodochy.org/ex/abstract/mileage.html
>
>This website estimates a 6% drop in car mileage from a 30 degreeF drop
>in temperature.

I don't think they factored in the volumetric efficiency the engine
gains from ingesting cooler air, but that's probably for the better in
terms of comparison to bicycles!

>Anyone else have some figures relating air density to temperature
>change, and its effect on bicycling?

The biggest effect is that the bicycles remain hanging in the garage
on cold days. Sigh...

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

[Mark Hickey]

wrote:

>Check out analytical cycling
>http://www.analyticcycling.com/ForcesPower_Page.html
>The air density increases by about 0.1 kg/m3 going from 60F to 20F and
>they say this demands an increase in power from about 275 watts to 285
>watts given all the same other parameters. That is only a 3.6%
>increase in power needed.

That would assume that you're still wearing shorts and a short sleeve
jersey while riding in 20F (-7C) temperatures of course. The
aerodynamic penalty for a jacket can be pretty dramatic.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

[Scott]

Mark Hickey wrote:
>
>
> The biggest effect is that the bicycles remain hanging in the garage
> on cold days. Sigh...

Mine is languishing in the basement. So at least it's
warm.


Scott

[Scott]

mort wrote:
> Colorado Bicycler wrote:
>
>>It seems to me that when I bike at about 40F or colder on my mtn bike
>>with 1.75 slicks, everything slows way down, including me!
>>
>>So, is it psychological, physical, the tires, the lubricant, SAD, or am
>>I just imagining things.
>
>
> Here's a chart of air temperature vs. density.
>
> http://www.ce.utexas.edu/prof/kinnas/319LAB/Book/CH1/PROPS/densgif.html
>
> I think that the effect is greater than posited by Analytic Cycling.
> It also seems to make sense that heating the body would take away some
> of the energy normally used to power muscles, although that may not be
> how it works at all. I certainly eat more after winter rides than I do
> in the summer.
>
> Mort
>

What a poorly chosen x axis. Air temperatures of 200 C indeed.
Like *that's* gonna happen.

Note that the difference between mid 80s and 32 (30 and 0 C)
is about 20%

Scott

[Scott]

Ron Hardin wrote:
> Colorado Bicycler wrote:
>
>>It seems to me that when I bike at about 40F or colder on my mtn bike
>>with 1.75 slicks, everything slows way down, including me!
>>
>>So, is it psychological, physical, the tires, the lubricant, SAD, or am
>>I just imagining things.
>
>
> 1. Denser air
>
> 2. You have to heat all the air you breathe to body temperature.
> The harder you work, the more air you have to heat as you breathe more.
> So you reach a calorie limit that's self-reenforcing pretty fast.
>

Air has a pretty low specific heat, i.e., it's
not too hard to warm it up, so I rather doubt
#2 has much of an effect.

A bigger effect probably occurs because the
colder air is dryer, leading to faster
dehydration through exhalation (and mucus
production :) ), so you have to carry more
water at a pound per pint.


Scott

[Ron Wallenfang]

"Mark Hickey" > wrote in message
...
> "Colorado Bicycler" > wrote:
>
>>http://www.xenodochy.org/ex/abstract/mileage.html
>>
>>This website estimates a 6% drop in car mileage from a 30 degreeF drop
>>in temperature.
>
> I don't think they factored in the volumetric efficiency the engine
> gains from ingesting cooler air, but that's probably for the better in
> terms of comparison to bicycles!
>
>>Anyone else have some figures relating air density to temperature
>>change, and its effect on bicycling?
>
> The biggest effect is that the bicycles remain hanging in the garage
> on cold days. Sigh...
>
> Mark Hickey
> Habanero Cycles
> http://www.habcycles.com
> Home of the $795 ti frame

There's no doubt that colder weather reduces speed, big time. I average
about 15 mph in warm weather, maybe 12 in slightly subfreezing temps and
barely 10 in very cold weather, say below 10 F. I wonder what factors are
involved and speculate about the following:

1. Air density
2. Bulky clothing
3. Less efficiency in the bearings
4. Inability to breathe hard for long
5. Breathing stale air when I have a mask on
6. General sluggishness
7. Greater percentage of riding in dark conditions

OTOH, I have a very good long term record of avoiding flat tires in the
winter (knock on wood) Why would that be?

[[email protected]]

STP means Standard Temperature and Pressure.
Standard Temperature is 0C right?
Why does that chart have the line at 32?
I think that scale is in F!

To calculate, 100C =373K Kelvin, 0C = 273 K
Ratio 373/273 = 1.366
40C = 313K, -10C = 263K, 313 / 263 = 1.19 (19 percent denser)
Also water vapor is lower density than air, and more water vapor at
high temps.

Scott wrote:
> mort wrote:
> > Colorado Bicycler wrote:
> >
> >>It seems to me that when I bike at about 40F or colder on my mtn bike
> >>with 1.75 slicks, everything slows way down, including me!
> >>
> >>So, is it psychological, physical, the tires, the lubricant, SAD, or am
> >>I just imagining things.
> >
> >
> > Here's a chart of air temperature vs. density.
> >
> > http://www.ce.utexas.edu/prof/kinnas/319LAB/Book/CH1/PROPS/densgif.html
> >
> > I think that the effect is greater than posited by Analytic Cycling.
> > It also seems to make sense that heating the body would take away some
> > of the energy normally used to power muscles, although that may not be
> > how it works at all. I certainly eat more after winter rides than I do
> > in the summer.
> >
> > Mort
> >
>
> What a poorly chosen x axis. Air temperatures of 200 C indeed.
> Like *that's* gonna happen.
>
> Note that the difference between mid 80s and 32 (30 and 0 C)
> is about 20%
>
> Scott

[Mark Hickey]

"Ron Wallenfang" > wrote:

>There's no doubt that colder weather reduces speed, big time. I average
>about 15 mph in warm weather, maybe 12 in slightly subfreezing temps and
>barely 10 in very cold weather, say below 10 F. I wonder what factors are
>involved and speculate about the following:
>
>1. Air density
>2. Bulky clothing
>3. Less efficiency in the bearings
>4. Inability to breathe hard for long
>5. Breathing stale air when I have a mask on
>6. General sluggishness
>7. Greater percentage of riding in dark conditions

I think most of the above are pretty valid - if you're wearing a mask,
you're certainly recycling some C02, and if it's dark it's reasonable
for the human brain to slow down a bit to try to protect itself. I am
less motivated in the winter just because I've decided that's my
"off-season" (even if the weather is actually pretty good - you can't
ride hammer and tongs all year round).

>OTOH, I have a very good long term record of avoiding flat tires in the
>winter (knock on wood) Why would that be?

It's just too cold to change a flat? ;-)

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

[wvantwiller]

"Colorado Bicycler" > wrote in
oups.com:

> Thanks for the input.
>
> But, even going down familiar hills, where I am not pedaling, the whole
> thing goes slower! I know this because I keep pretty good track of my
> coasting downhill speeds.
>
I've got a 4% grade hill on one end of my circuit and a lower 3% on the
other, and I've noted a general decrease in top speed going down the taller
hill where the effects of air resistance would be most pronounced. About
29mph where 32mph was normal, in a repeatable manner. That's about 10%.

That's in ~40 degree vs ~80 degree temperatures, pedalling all the way,
with intermediate points showing about the same for both temperatures
(i.e., I pass the 10mph, 21mph points about the same place regardless of
temperature). I go over a 1.44 mile circuit for multiple laps, but even
then the differences seem to be beyond normal variability. When the
temperatures drop I rarely get over 30mph by the bottom, while 32mph is
routine. It's a 30mph zone so I don't feel too bad being +/- 10% of the
limit, and that's why I notice the speed.

I'd also submit that the effect of slight breezes are more pronounced.

[Scott]

[Reformatted: I undid the top posting]

wrote:
> Scott wrote:
>
>>mort wrote:
>>
>>>Colorado Bicycler wrote:
>>>
>>>
>>>>It seems to me that when I bike at about 40F or colder on my mtn bike
>>>>with 1.75 slicks, everything slows way down, including me!
>>>>
>>>>So, is it psychological, physical, the tires, the lubricant, SAD, or am
>>>>I just imagining things.
>>>
>>>
>>>Here's a chart of air temperature vs. density.
>>>
>>>http://www.ce.utexas.edu/prof/kinnas/319LAB/Book/CH1/PROPS/densgif.html
>>>
>>> I think that the effect is greater than posited by Analytic Cycling.
>>>It also seems to make sense that heating the body would take away some
>>>of the energy normally used to power muscles, although that may not be
>>>how it works at all. I certainly eat more after winter rides than I do
>>>in the summer.
>>>
>>>Mort
>>>
>>
>>What a poorly chosen x axis. Air temperatures of 200 C indeed.
>>Like *that's* gonna happen.
>>
>>Note that the difference between mid 80s and 32 (30 and 0 C)
>>is about 20%
>>
>>Scott
>
>
> STP means Standard Temperature and Pressure.
> Standard Temperature is 0C right?
> Why does that chart have the line at 32?
> I think that scale is in F!
>
> To calculate, 100C =373K Kelvin, 0C = 273 K
> Ratio 373/273 = 1.366
> 40C = 313K, -10C = 263K, 313 / 263 = 1.19 (19 percent denser)
> Also water vapor is lower density than air, and more water vapor at
> high temps.

The tic is at 30 C, and the standard temperature they've
chosen is 25C/77 F. That's what I see when I click on
the image and it pops up a larger version. Maybe the
software they used to make the smaller thumbnail has
some bugs in it. :)

Water vapor is at most 4% of the atmosphere -- and NO
one is gonna want to bike in *that* kind of humidity.
The difference between moist air and dry air density is
small. The far bigger difference is the effect of the
change in evaporation rates that occur as humidity increases.

Scott

[SlowRider]

mort wrote:
> Here's a chart of air temperature vs. density.
>
> http://www.ce.utexas.edu/prof/kinnas/319LAB/Book/CH1/PROPS/densgif.html
>
> I think that the effect is greater than posited by Analytic Cycling.

Just another data point on air density. I remember reading somewhere a
few years ago that cyclists who train at high altitudes shouldn't
expect to go faster at sea level, and may even go a bit slower since
the increased air density at low elevations more than compensates for
any improved lung capacity. The same principal probably applies to
cold vs. warm temperatures.


-JR