C
On Nov 26, 8:50 am, [email protected] wrote:
> On Nov 25, 10:28 pm, [email protected] wrote:
> > On Sun, 25 Nov 2007 20:12:29 -0700, [email protected] wrote:
> > >On Sun, 25 Nov 2007 17:30:49 -0800 (PST), bicycle_disciple
> > ><[email protected]> wrote:
>
> > >>Is there any truth to the fact that in early the early Tours, racers
> > >>inflated tires with CO2.
>
> > >>Supposedly, even race car tires use this gas because of its higher
> > >>consistency than normal air pressure, over varying tire and track
> > >>temperatures. Is this possible in the realm of bicycle tires, since I
> > >>think due to such higher pressures, leakage is elevated? Yet I deem
> > >>the benefits could be minutely small.
>
> > >>And how does the temperature of the air sitting in the tire vary? I'd
> > >>like to see some references to this because some doofus on a bike
> > >>forum thinks air temperature is roughly constant in the long high
> > >>speed descent. That surely can't be possible because of rim heating,
> > >>no?
>
> > >Dear BD,
>
> > >You may have confused N2 in your title and CO2 in your text.
>
> > >Back in the 60's, riders inflated tires with nitrogen from bulky
> > >canisters (gonfleurs) about the size of a mini-pump, often attached
> > >below the downtube.
>
> > >Since the air that you breathe is 80% N2 and 20% O2 (the CO2, water
> > >vapor, and trace gases are about 1%), the N2 from the canister wasn't
> > >much different than what a pump put into the bike tire, so it didn't
> > >leak out much faster.
>
> > >CO2 is used today for quick-inflate because it's cheaply available in
> > >much smaller cartridges because it can be liquified at reasonable
> > >pressures.
>
> > >The trouble with CO2 is that it goes through butyl rubber more than 10
> > >times as fast, so riders who use CO2 for quick fixes on the road find
> > >that they have to pump the tire up a few days later--not exactly the
> > >worst problem ever suffered by bicyclists.
>
> > >For race cars, using pure N2 eliminates the water vapor, which has a
> > >nasty habit of condensing and going back to vapor at race car tire
> > >temperatures, leading to small pressure changes that matter to race
> > >cars, but not to bicycles.
>
> > >Cheers,
>
> > >Carl Fogel
>
> > Here's agonfleur:
>
> >http://images.google.com/imgres?imgurl=http://www.theracingbicycle.co....
>
> > A look in the RBT archives shows that I found pictures of gonfleurs
> > back to 1926:
>
> > http://groups.google.com/group/rec.bicycles.tech/msg/f4f84c6a7b457774
>
> > Riders often carried a pump _and_ agonfleur:
>
> > http://i182.photobucket.com/albums/x300/garyf5354/DSC00131.jpg
>
> > Cheers,
>
> > Carl Fogel
>
> Cool. How much did a cannister weigh about?- Hide quoted text -
Dear Ron,
Still no details about weight, but I stumbled over this 1949 ad:
http://www.wooljersey.com/gallery/v/aldoross/pd/LDC.jpg.html
No price, no weight, no details, but all the road giants use them!
Cheers,
Carl Fogel
> On Nov 25, 10:28 pm, [email protected] wrote:
> > On Sun, 25 Nov 2007 20:12:29 -0700, [email protected] wrote:
> > >On Sun, 25 Nov 2007 17:30:49 -0800 (PST), bicycle_disciple
> > ><[email protected]> wrote:
>
> > >>Is there any truth to the fact that in early the early Tours, racers
> > >>inflated tires with CO2.
>
> > >>Supposedly, even race car tires use this gas because of its higher
> > >>consistency than normal air pressure, over varying tire and track
> > >>temperatures. Is this possible in the realm of bicycle tires, since I
> > >>think due to such higher pressures, leakage is elevated? Yet I deem
> > >>the benefits could be minutely small.
>
> > >>And how does the temperature of the air sitting in the tire vary? I'd
> > >>like to see some references to this because some doofus on a bike
> > >>forum thinks air temperature is roughly constant in the long high
> > >>speed descent. That surely can't be possible because of rim heating,
> > >>no?
>
> > >Dear BD,
>
> > >You may have confused N2 in your title and CO2 in your text.
>
> > >Back in the 60's, riders inflated tires with nitrogen from bulky
> > >canisters (gonfleurs) about the size of a mini-pump, often attached
> > >below the downtube.
>
> > >Since the air that you breathe is 80% N2 and 20% O2 (the CO2, water
> > >vapor, and trace gases are about 1%), the N2 from the canister wasn't
> > >much different than what a pump put into the bike tire, so it didn't
> > >leak out much faster.
>
> > >CO2 is used today for quick-inflate because it's cheaply available in
> > >much smaller cartridges because it can be liquified at reasonable
> > >pressures.
>
> > >The trouble with CO2 is that it goes through butyl rubber more than 10
> > >times as fast, so riders who use CO2 for quick fixes on the road find
> > >that they have to pump the tire up a few days later--not exactly the
> > >worst problem ever suffered by bicyclists.
>
> > >For race cars, using pure N2 eliminates the water vapor, which has a
> > >nasty habit of condensing and going back to vapor at race car tire
> > >temperatures, leading to small pressure changes that matter to race
> > >cars, but not to bicycles.
>
> > >Cheers,
>
> > >Carl Fogel
>
> > Here's agonfleur:
>
> >http://images.google.com/imgres?imgurl=http://www.theracingbicycle.co....
>
> > A look in the RBT archives shows that I found pictures of gonfleurs
> > back to 1926:
>
> > http://groups.google.com/group/rec.bicycles.tech/msg/f4f84c6a7b457774
>
> > Riders often carried a pump _and_ agonfleur:
>
> > http://i182.photobucket.com/albums/x300/garyf5354/DSC00131.jpg
>
> > Cheers,
>
> > Carl Fogel
>
> Cool. How much did a cannister weigh about?- Hide quoted text -
Dear Ron,
Still no details about weight, but I stumbled over this 1949 ad:
http://www.wooljersey.com/gallery/v/aldoross/pd/LDC.jpg.html
No price, no weight, no details, but all the road giants use them!
Cheers,
Carl Fogel
