multiple pumps in odd places?
carl...@comcast.net
Centennial 1903-2003," a mammoth coffe-table book from the
library, when I began noticing that something was odd about
the pumps back in the early days.
On page 89, a huge picture of Lucien Buysse, the winner in
1926, gives a clear example. He has two pumps on his frame,
one leaning forward inside the front diamond, and the other
leaning backward between the rear tire and the seat post.
Why carry two pumps? Could one be some bizarre tool that
just looks like a pump? Or did riders expect to damage one
pump whacking aggressive dogs and spectators and need a
spare pump?
Why do so many early pictures show single pumps hanging
behind the seat post? Apart from what it says about frame
clearance, isn't it a poor place to put a detachable hand
too, exposing it to mud on the dirt roads while running the
risk of it tangling up in the wheel?
Somehow I doubt that those guys were stupid, so I suspect
that there's an explanation.
The last pumps that I spotted were in the 1959 Tour
pictures, and they were even weirder. On page 198,
Bahamontes, Anquetil, and Riviere all appear to have short
mini-pumps (or maybe long CO2 tanks?) mounted down low on
the outside of the downtube, perfectly positioned to keep
spray from the front tire from spattering the frame.
What was going on?
Carl Fogel
Scott Goldsmith
> pictures, and they were even weirder. On page 198,
> Bahamontes, Anquetil, and Riviere all appear to have short
> mini-pumps (or maybe long CO2 tanks?) mounted down low on
> the outside of the downtube, perfectly positioned to keep
> spray from the front tire from spattering the frame.
>
> What was going on?
>
> Carl Fogel
The behind the seatpost widgets are "gonfleurs", compressed air inflators.
Nothing is new in bicycling, everything has been invented at least twice.
Frame clearance was more in the bad old days of unpaved roads,
400 kilometer stages and no team cars, bikes had to be more comfortable
and reliable. Think how much fun a Jobst Brandt style unpaved 300k
mountain stage would be without radios and team cars, Real Racin'
as Junior Johnson used to say.
Scott Goldsmith
Now where is my Rema Tip Top Cardon fork repair kit ?
Tom Nakashima
"Scott Goldsmith" <sg8...@getcoactive.com> wrote in message
news:e8e69f4c.04082...@posting.google.com...
In my elementary school days, I had a Schwinn Varsity 10sp, yes a real 10
speed with a cluster of 5 on the rear. We played baseball at the school
yard on the weekends, and I used to transport my Mickey Mantle bat (real
bats are made of wood) to the baseball field in the drops of the bar, with
my glove dangling on the loop. I guess this might count as a odd place to
carry a pump, but I actually did transport a Silca floor pump to work once
by this method. One rider yelled to me, "Hey, have you ever heard of frame
pumps?" I had an extra Silca floor pump to give to my friend at work
-tom
carl...@comcast.net
Goldsmith) wrote:
Dear Scott,
The older 1926 behind-the-seat-post ones really do look like
long modern hand pumps, just tucked away in an odd place.
The odd short ones below the down tube in 1959 might well be
air tanks--the level of detail in the picture isn't good
enough to be sure, but they look sort of solid, like
cannisters, with no visible line where a pump handle slides
down over the body.
Another picture in the same book on page 193 from 1957
shows the odd short ones from a different angle with their
short air hoses dangling free under the bottom bracket,
presumably clogging with dust and mud.
I'm still wondering why they were stored in such odd places.
Carl Fogel
jobst....@stanfordalumni.org
> The older 1926 behind-the-seat-post ones really do look like
> long modern hand pumps, just tucked away in an odd place.
You mean like the one in this picture?
> The odd short ones below the down tube in 1959 might well be
> air tanks--the level of detail in the picture isn't good
> enough to be sure, but they look sort of solid, like
> cannisters, with no visible line where a pump handle slides
> down over the body.
> Another picture in the same book on page 193 from 1957
> shows the odd short ones from a different angle with their
> short air hoses dangling free under the bottom bracket,
> presumably clogging with dust and mud.
> I'm still wondering why they were stored in such odd places.
Behind the seat tube means the pump isn't dislodged when carrying the
bicycle over ones shoulder as I do on occasions like going over the
Col Ferret that is too steep to push a bicycle. On local rides, I
need to carry the bicycle as well on some of the forest roads.
Jobst Brandt
jobst....@stanfordalumni.org
bfd
<jobst....@stanfordalumni.org> wrote in message
news:ILqXc.9879$54.1...@typhoon.sonic.net...
In addition to carrying a pump *behind* the seat tube is to place one along
the left seatstay/above the left chainstay, like here:
http://www.bikefanclub.com/gallery/showphoto.php?photo=525&password=&sort=1&cat=506&page=1
This position allows me to carry a full frame pump and is out of the way if
I need to carry my bike over my shoulder.
carl...@comcast.net
Dear Jobst,
Aha!
That might explain both the behind-the-seat-tube and the
back-of-the-down-tube positions.
Even if the Tour riders back then never faced stretches of
road bad enough to make them carry their bikes, they would
have naturally placed their pumps where ordinary riders
likely to carry road bikes were placing their pumps.
Thanks,
Carl Fogel
John Thurston
> Why do so many early pictures show single pumps hanging
> behind the seat post? Apart from what it says about frame
> clearance, isn't it a poor place to put a detachable hand
> too, exposing it to mud on the dirt roads while running the
> risk of it tangling up in the wheel?
I've carried the pump behind the seat on my mountain bike for years.
In the early days (about the first four years) I had a plug that I
kept in the pump head to keep the dirt and mud out. I finally lost
that bit so have carried the pump "unplugged" for the last twelve
years.
It has never fallen off, or presented any danger to my rear wheel or
tire. The sticks in the trails and trees to the sides concern me far
more than my pump tangling in my wheel.
Yes, it does get some dirt in it. Before I use it, I lightly cover
the hole with my thumb and give it a few fast pumps to blow the mud
out. If it is really caked up I may need to first splash some water
on it from my bottle.
Behind the post is a great place to keep that pump. I highly
recommend it.
John Thurston
Juneau, Alaska
Trevor
carl...@comcast.net wrote in message ...
spectators.
Trevor
A Muzi
The small 1960s things are gonfleurs, mini compressed
nitrogen cyinders.
I don't know about any double pump convention, sorry.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
carl...@comcast.net
Dear Andrew,
Why nitrogen instead of CO2?
I looked back through the pictures. It's surprising how hard
it is to find clear shots of the damned things, but I found
more and more of them.
Some of the behind-the-seat-post ones turn out to be short
tanks, not pumps, but others are clearly long hand-pumps.
Many of the bikes with short tanks behind-the-seat-post also
carry long hand pumps mounted on the inside of the
down-tube.
For some reason, pumps are carried on the inside of the
down-tube, but the short tanks are carried on the outside of
the down-tube when they're not behind the seat-post. Some
pictures even show the empty tank clips under the down tube,
presumably on short speed stages.
The earliest picture that I can find so far of a short tank
behind-the-seat-post is a profile of Bartali on his way to
second place in 1949. It's opposite a picture of an
anguished Kubler with a pump in one hand, fixing a flat.
Carl Fogel
Trevor
>
Gas pressure differential for nitrogen filled tubes to atmosphere is lower
than that for carbon dioxide and so will lose pressure through permeation at
a slower rate.
Do not know over what period this would be significant.
Trevor
Peter
> carl...@comcast.net wrote in message ...
>
>>Why nitrogen instead of CO2?
>>
> Gas pressure differential for nitrogen filled tubes to atmosphere is lower
> than that for carbon dioxide and so will lose pressure through permeation at
> a slower rate.
Nitrogen will permeate through the rubber tube at a slower rate, but I
don't understand your comment about a lower pressure differential.
If I fill my tires to 100 psi-gauge (assume that pressure is needed to
avoid pinch flats), then the pressure differential relative to the
atmosphere will be 100 psi regardless of whether air, nitrogen, or
carbon dioxide are used to fill them.
The greater permeation rate of carbon dioxide is due to its high
solubility in rubber as a result of the affinity of the carbon
dioxide molecules for the long carbon chains in the rubber.
Nitrogen and oxygen molecules tend to bounce off the rubber but
carbon dioxide molecules stick to it and become absorbed by the
rubber. They are then able to slowly migrate through the rubber
and eventually escape from the tube. See
http://www.madsci.org/posts/archives/may98/895552329.Ch.r.html
for additional description.
Robin Hubert
> On Thu, 26 Aug 2004 19:31:23 GMT, "bfd" <bfd...@mindspring.com> wrote:
>
> >http://www.bikefanclub.com/gallery/showphoto.php?photo=525&password=&sort=1&cat=506&page=1
>
> I do that too, with the same pump.
>
> JT
Me too, me too, me too! JK
One note regarding this pump placement is that, in rainy rides, the
handle end gets filled with grit, making it impossible to turn the
lockout lever without first disassembling and cleaning the handle.
I've tried riding it with the head down, but doesn't clear the spokes
(?) or something. I don't remember exactly, though I'm pretty sure I
tried it.
Robin Hubert
B.B.
Peter <prat...@comcast.net> wrote:
[...]
>The greater permeation rate of carbon dioxide is due to its high
>solubility in rubber as a result of the affinity of the carbon
>dioxide molecules for the long carbon chains in the rubber.
>Nitrogen and oxygen molecules tend to bounce off the rubber but
>carbon dioxide molecules stick to it and become absorbed by the
>rubber. They are then able to slowly migrate through the rubber
>and eventually escape from the tube. See
>http://www.madsci.org/posts/archives/may98/895552329.Ch.r.html
>for additional description.
Question: is the diffusion of CO2 into the rubber promoted by the
pressure within the tube? If so would a deflated tube partially
reinflate again due to CO2 evaporating out of the rubber of the inside
walls?
--
B.B. --I am not a goat! thegoat4 at airmail.net
Peter
There would be an equilibrium reached between CO2 molecules sticking to
the inside wall of the tube and molecules that had previously become
absorbed being released. A sudden drop in pressure would shift
the equilibrium since fewer CO2 molecules would be hitting the wall, but
the effect would be tiny. The inner tube is pretty thin and
doesn't hold very much CO2 and only a small fraction of that would be
released.
Robin Hubert
Excuse me, Jobst, but how about in front of the seat tube, where
there's no crud being flung up by the rear wheel. As I understand it,
you don't use water bottles, so this ought to be a good position.
Robin Hubert
carl...@comcast.net
Hubert) wrote:
Dear Robin,
In front of the seat tube, a long frame pump running up and
down would probably get knocked loose when Jobst puts his
shoulder through the frame where the top tube and the seat
tube meet.
On the other hand, running a long frame tube diagonally up
from the bottom bracket to the stem inside the frame would
work--and that's where a number of the riders with both long
pumps and short behind-the-seat-post tanks carry their pumps
in the older pictures.
Carl Fogel
Trevor
Peter wrote in message ...
Only compare like with like regarding pressure differentials Air is made up
of 80% nitrogen and lesser amounts of other gases. permeation occurs
because the absolute pressure of the gas is lower on one side of the
membrane than the other. Air would be best to fill tubes but nitrogen comes
close because it is close to air itself.
Trevor