CO2 Inflators

[Guy Goldich]

I've used a Zefal HPX frame pump for the last 15 years or
so without problems. I usually carry 2 inner tubes and a
patch kit.

However, at my local bike shop, my eye has been straying
over to the CO2 inflators. Most of my rides are between 20
and 40 miles. I've heard that since CO2 is a smaller
molecule, tires lose air quicker.What has been people's
experience with them? Viable alternative? Weight &
reliability?

 

[Cipher]

Originally posted by Guy Goldich
I've used a Zefal HPX frame pump for the last 15 years or
so without problems. I usually carry 2 inner tubes and a
patch kit.

However, at my local bike shop, my eye has been straying
over to the CO2 inflators. Most of my rides are between 20
and 40 miles. I've heard that since CO2 is a smaller
molecule, tires lose air quicker.What has been people's
experience with them? Viable alternative? Weight &
reliability?

I've used one for approx. 3 years now, and aside from the very first time (I didn't read the directions, hey I'm a guy, what du ya expect?) it's never failed me. I usually ride with 2 tubes an a pair of 12g. cylinders. I can't comment on their loosing the CO2 faster, but I have also heard it's an issue. (I deflate and re-inflate with a floor pump when I get home anyways). I personally would not go back to a frame pump. My 2¢.

 

[carlfogel]

Originally posted by Guy Goldich
I've used a Zefal HPX frame pump for the last 15 years or
so without problems. I usually carry 2 inner tubes and a
patch kit.

However, at my local bike shop, my eye has been straying
over to the CO2 inflators. Most of my rides are between 20
and 40 miles. I've heard that since CO2 is a smaller
molecule, tires lose air quicker.What has been people's
experience with them? Viable alternative? Weight &
reliability?

Dear Guy,

Apart from the question of which molecules you
have in mind (which I leave in good hands), there's
the question of practicality and reliability.

Whoosh! Oops, that spare tube that's been sitting
in your bag for months turns out not to hold air.
Hope the other tube works. Hope your other CO2
cartridge works. Hope you don't get another flat.

Whoosh! Bang! Could have sworn that the tire was
seated properly. Never made a mistake like that
before, so make a note to write bitter post to
rec.bicycles.tech about inferior tire brand. Couldn't
possibly have been my fault.

Whoosh . . . fizzz . . . goddamned valve is leaking!
Bent or defective or something.

Whoosh! There, that's the front tire. Whoosh! And
that's the back tire. Hope I don't hit another patch
of whatever the hell gave both of them flats--only
twenty more miles to go.

In short, a bike pump keeps working as long as
you need it, while CO2 cartridges tend to run
out in bad situations, even when you need only
one more.

Three other points prejudice me against CO2:

1. I don't want to hesitate when I finally spot
a gorgeous super-model stranded with a flat
by the side of the road. With only CO2, I'd
hesitate to give her one of my precious cartridges,
just as I'd hesitate to give her my morphine
styrette on a battlefield--I might need it myself.
With a pump, however, I can string things out
without a care, chatting while she admires my
tire-inflation technique (and secretly wishes that
I had a CO2 cartridge so that she wouldn't have
to listen to me prattle).

2. So far this year, I'd have used 14 CO2 cartridges
to fix my flats. They're only a buck or so each, and
I waste far more on tubes, but I can buy nice pumps
for less than $50 per year and can use the exercise.

3. "Summer is a-coming in, Loud sing cuckoo . . ."
No cuckoos around here, but I expect to see a
rattlesnake coiled up and rattling on the bike
path before May. An extended bike pump works
to shoo them off, but I doubt that waving a CO2
cartridge at them has the same effect.

Carl Fogel

 

[Jim Flom]

"Guy Goldich" wrote ...
> I've used a Zefal HPX frame pump for the last 15 years or
> so without problems. I usually carry 2 inner tubes and a
> patch kit.
>
> However, at my local bike shop, my eye has been straying
> over to the CO2 inflators. Most of my rides are between 20
> and 40 miles. I've heard that since CO2 is a smaller
> molecule, tires lose air quicker.What has been people's
> experience with them? Viable alternative? Weight &
> reliability?

Two tubes and a patch kit for a 40 mile ride? You certainly
are prepared, I'll grant you that. Whatever any supposed
loss of air pressure, you really just need something to hold
you over till you get home anyway, right? My "ULTRAFLATE"
jacks up the tire pressure to around 100 pounds way more
easily than a hand pump would, and if you want you can pack
an extra cartridge or two in case you get that second flat,
you certainly can. Just make sure you match your carttridge
refills to the gauge refill your applicator takes.

Jim Flom

 

[Erik Lindeberg]

"Guy Goldich" <[email protected]> wrote in message
news[email protected]...
> I've heard that since CO2 is a smaller molecule, tires
> lose air quicker.What has been people's experience with
> them? Viable alternative? Weight & reliability?
>
Small molecules e.g. helium, may diffuse faster than larger
molecules through some materials. The CO2 molecule is,
however, larger than the main constituents of air, oxygen
and nitrogen, both with respect to molecular weight and
size. There are other properties, though, that contribute to
how fast the gas molecules diffuses through the rubber, in
particular how easy they dissolve in rubber.

Occasionally I have been using CO2 cartridges to pump
up my tires and I have not notice that CO2 leaks out
faster than air.

Erik

 

[E. Willson]

CO2 will indeed diffuse through rubber faster than air.
Scientifically, I am saying that its diffusion coefficient
is significantly higher. I do not use it, so I cannot tell
you what to practically expect. I have heard people say
that they needed to pump up tires filled with CO2 after two
days. YMMV.

HTH Ernie

Guy Goldich wrote:

> I've used a Zefal HPX frame pump for the last 15 years or
> so without problems. I usually carry 2 inner tubes and a
> patch kit.
>
> However, at my local bike shop, my eye has been straying
> over to the CO2 inflators. Most of my rides are between 20
> and 40 miles. I've heard that since CO2 is a smaller
> molecule, tires lose air quicker.What has been people's
> experience with them? Viable alternative? Weight &
> reliability?

 

[Christopher Mey]

I stopped using a pump a couple of years ago. My rides are
between 20 and 55 miles and to be frank, I love 'em. I've
never had a significant pressure loss due to molecular size
after fixing. My preference for road use is the 16g
cartridges.

CM

"Guy Goldich" <[email protected]> wrote in message newsfCdnRUHuuYIqO7dRVn-
[email protected]...
> I've used a Zefal HPX frame pump for the last 15 years or
> so without problems. I usually carry 2 inner tubes and a
> patch kit.
>
> However, at my local bike shop, my eye has been straying
> over to the CO2 inflators. Most of my rides are between 20
> and 40 miles. I've heard that since CO2 is a smaller
> molecule, tires lose air quicker.What has been people's
> experience with them? Viable alternative? Weight &
> reliability?

 

[Steve Knight]

On Tue, 06 Apr 2004 21:21:38 -0400, "E. Willson" <[email protected]> wrote:

>CO2 will indeed diffuse through rubber faster than air.
>Scientifically, I am saying that its diffusion coefficient
>is significantly higher. I do not use it, so I cannot tell
>you what to practically expect. I have heard people say
>that they needed to pump up tires filled with CO2 after two
>days. YMMV.

I did. and the tire once I let the CO2 out never went flat
again for a couple weeks then it just needed topped off.

--
Knight-Toolworks & Custom Planes Custom made wooden planes
at reasonable prices See http://www.knight-toolworks.com For
prices and ordering instructions.

 

[Psycholist]

"Guy Goldich" <[email protected]> wrote in message
news[email protected]...
> I've used a Zefal HPX frame pump for the last 15 years or
> so without problems. I usually carry 2 inner tubes and a
> patch kit.
>
> However, at my local bike shop, my eye has been straying
> over to the CO2 inflators. Most of my rides are between 20
> and 40 miles. I've heard that since CO2 is a smaller
> molecule, tires lose air quicker.What has been people's
> experience with them? Viable alternative? Weight &
> reliability?
>

They get you back on the road faster and they get you home
where you can/should dismount the flatted tire for further
inspection, and where you can reinflate it with good 'ol
American air.

Bob C.

 

[David Damerell]

Guy Goldich <[email protected]> wrote:
>I've used a Zefal HPX frame pump for the last 15 years or
>so without problems. I usually carry 2 inner tubes and a
>patch kit. However, at my local bike shop, my eye has been
>straying over to the CO2 inflators.

You should consider the correct technique for using these;
when they let you down, stand at the side of the road
looking pathetic until someone with an HPX (like me) comes
by, mocks you gently, and pumps up your tyre.

CO2's all very well _except_ for the worst-case scenario,
and then you're completely shafted. In contrast with a patch
kit as well as spare tubes you're good for eight or so
punctures in one day, and if by some hideous mischance that
_does_ happen, you only have to scrounge another patch off a
passer-by.

If you can live with the idea that very occasionally you'll
be begging cager friends to come and rescue you, fine;
otherwise, stick with the pump.

Don't be concerned, though, about the extra leakage of CO2.
It won't make any difference on the day, and later you can
always reinflate it with air at home.
--
David Damerell <[email protected]> Kill
the tomato!

 

[Jeff Starr]

"Guy Goldich" <[email protected]> wrote in message news:<[email protected]>...
> I've used a Zefal HPX frame pump for the last 15 years or
> so without problems. I usually carry 2 inner tubes and a
> patch kit.
>
> However, at my local bike shop, my eye has been straying
> over to the CO2 inflators. Most of my rides are between 20
> and 40 miles. I've heard that since CO2 is a smaller
> molecule, tires lose air quicker.What has been people's
> experience with them? Viable alternative? Weight &
> reliability?

Hi, I carry a CO2 inflator and for side of the road repairs,
it is just fine. Before I bought a decent floor pump, I did
use my inflator to maintain pressure. It did seem like they
went down a little faster, but we are talking days, not
hours. So an inflator used as designed is not a problem. For
home use, I have a Topeak Joe Blow Sport. Be sure to get an
inflator that will take both threaded and unthreaded
cartridges. It is much cheaper to buy your refills at a
store that sells them by the box for use in pellet/paintball
guns. Life is Good! Jeff

 

[John Rees]

"David Damerell" <[email protected]> wrote in message
news:bJq*[email protected]...
| Guy Goldich <[email protected]> wrote:
| >I've used a Zefal HPX frame pump for the last 15 years or
| >so without problems. I usually carry 2 inner tubes and a
| >patch kit. However, at my local bike shop, my eye has
| >been straying over to the
CO2
| >inflators.
|
| You should consider the correct technique for using these;
| when they
let
| you down, stand at the side of the road looking pathetic
| until someone with an HPX (like me) comes by, mocks you
| gently, and pumps up your
tyre.
|
| CO2's all very well _except_ for the worst-case scenario,
| and then
you're
| completely shafted. In contrast with a patch kit as well
| as spare
tubes
| you're good for eight or so punctures in one day, and
| if by some
hideous
| mischance that _does_ happen, you only have to scrounge
| another patch
off
| a passer-by.
|
| If you can live with the idea that very occasionally
| you'll be begging cager friends to come and rescue you,
| fine; otherwise, stick with the pump.
|
| Don't be concerned, though, about the extra leakage of
| CO2. It won't
make
| any difference on the day, and later you can always
| reinflate it with
air
| at home.

I never believed this story about CO2 'leaking faster' than
plain air, so I looked at some atomic references:

First, the following is the composition of the earths
atmosphere:

Nitrogen 78% Oxygen 20% CO2 0.033%

OK. So not much CO2 in the air we breathe So then I looked
at the atomic weight of the elements I'm examining:

Nitrogen 14 Oxygen 16 Carbon 12

Finally, I calculated the molecular mass of these compounds:
Molecular mass:

N2 28 O2 32 CO2 44

So CO2 has a higher mass than either Nitrogen (most of our
air) and O2. How do these big molecules manage to sneak out
of your tube faster than air?

I think it's just a matter that you really don't know how
much air you managed to get into the tube with CO2
cartridges. I use the 'second wind' inflator. Best of both
worlds. It's a mini pump that accepts CO2 cartridges. Not a
great pump, but it beats walking in cleats. Also, I use the
pump feature when putting the tube back in to make sure I've
got all the kinks worked out before using the cartridge.

John Rees

 

[Peter]

John Rees wrote:

> I never believed this story about CO2 'leaking faster'
> than plain air,
...
> N2 28 O2 32 CO2 44
>
> So CO2 has a higher mass than either Nitrogen (most of our
> air) and O2. How do these big molecules manage to sneak
> out of your tube faster than air?

The problem is neither the physical size nor the molecular
weight. But CO2 does diffuse through thin rubber membranes
faster than N2 or O2. I believe the reason is that CO2 with
its carbon-oxygen double bonds is attracted to the rubber
molecules on the inside of the tube. Once 'stuck' to the
rubber it can gradually diffuse through the tube to the
outer surface. O2 and N2 don't have such an affinity to
rubber molecules so they are more likely to just hit and
bounce off

 

[Werehatrack]

On Tue, 6 Apr 2004 18:56:20 -0400, "Guy Goldich" <[email protected]>
may have said:

>I've used a Zefal HPX frame pump for the last 15 years or
>so without problems. I usually carry 2 inner tubes and a
>patch kit.
>
>However, at my local bike shop, my eye has been straying
>over to the CO2 inflators. Most of my rides are between 20
>and 40 miles. I've heard that since CO2 is a smaller
>molecule, tires lose air quicker.What has been people's
>experience with them? Viable alternative? Weight &
>reliability?

Weight, for one puncture, about the same as a light pump.
For four or more inflations of a road tire, or two mtb
fills, CO2 is going to be heavier. There is, as another
poster pointed out, a more important consideration: Once
you've used the last cartridge, your CO2 inflator (unless
it is incorporated into a pump) is useless to fill
another tire.

I carry a pump. It requires no cartridges. I am more
comfortable knowing that reinflating a tire will always take
a certain *longer* amount of time, regardless of how many
flats I have, than knowing that the n+1 flat will leave me
with no ride.

In a competition situation, with a chase vehicle to carry
the carts, I'd have CO2 as a backup to the high-pressure air
bottle and the 12V compressor.

The leakage issue is a non-concern if you check your
pressures each day before you set out.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

 

[Andrew Webster]

"John Rees" <[email protected]> wrote in message news:<[email protected]>...
><cut>
>
> I never believed this story about CO2 'leaking faster'
> than plain air, so I looked at some atomic references:
>
<cut>
> So CO2 has a higher mass than either Nitrogen (most of our
> air) and O2. How do these big molecules manage to sneak
> out of your tube faster than air?
<cut>
> John Rees

The theory is well covered here:

http://www.cus.cam.ac.uk/~jae1001/teaching/materials/M6_Lec-
ture_6.pdf

There is no mystery about it. The mechanism is well
understood.

The key point is that it's not just a simple case of
diffusion. Sorption of gases also plays a part in
gaseous transfer.

Basically the CO2 "dissolves" in the rubber and is
transported across the tube, then released. For efficient
transfer a gas needs to dissolve well and be readily
released into the air once it has diffused across the tube.
CO2 has appropriate intermolecular forces to "dissolve" in
the rubber and the low concentration outside helps its
release (think of both take up and release as equilibrium
processes, high concentration (partial pressure) of CO2
inside the tube helps drive take up by the rubber, low
concentration (partial pressure) outside helps drive the
release of CO2 once it has diffused across).

Andrew Webster

 

[landon2]

What's wrong with carrying a small frame pump as a back-up
to the CO2 inflator. Two carts (two flats) and if the worst
case scenario occurs, the pump is there. I know weight
weenies will scream, but if you're that concerned, belt and
suspenders. Besides, I always understood that if you carry
the pump in your back pocket, it doesn't count as weight on
the bike (kinda like the diet that says if nobody saw you
eat it, calories don't count).

Chuck

On 07 Apr 2004 14:28:25 +0100 (BST), David Damerell
<[email protected]> wrote:

>Guy Goldich <[email protected]> wrote:
>>I've used a Zefal HPX frame pump for the last 15 years or
>>so without problems. I usually carry 2 inner tubes and a
>>patch kit. However, at my local bike shop, my eye has been
>>straying over to the CO2 inflators.
>
>You should consider the correct technique for using these;
>when they let you down, stand at the side of the road
>looking pathetic until someone with an HPX (like me) comes
>by, mocks you gently, and pumps up your tyre.
>
>CO2's all very well _except_ for the worst-case scenario,
>and then you're completely shafted. In contrast with a
>patch kit as well as spare tubes you're good for eight or
>so punctures in one day, and if by some hideous mischance
>that _does_ happen, you only have to scrounge another patch
>off a passer-by.
>
>If you can live with the idea that very occasionally you'll
>be begging cager friends to come and rescue you, fine;
>otherwise, stick with the pump.
>
>Don't be concerned, though, about the extra leakage of CO2.
>It won't make any difference on the day, and later you can
>always reinflate it with air at home.

 

[Garyg]

"Guy Goldich" <[email protected]> wrote in message
news[email protected]...
> I've used a Zefal HPX frame pump for the last 15 years or
> so without problems. I usually carry 2 inner tubes and a
> patch kit.
>
> However, at my local bike shop, my eye has been straying
> over to the CO2 inflators. Most of my rides are between 20
> and 40 miles. I've heard that since CO2 is a smaller
> molecule, tires lose air quicker.What has been people's
> experience with them? Viable alternative? Weight &
> reliability?
>

Perhaps it's a California thing, but none of my road biking
friends carries a frame pump. Some of my mountain biking
friends carry both CO2 and a mini-pump inside their
Camelbacks...but, they typically ride far off the beaten
track, on trails with sharp rocks and thorns.

On my normal road rides (25-50 miles), I carry 2 or 3
cartridges in a small seat bag, along with a spare tube
(and, sometimes a patch kit). On longer and/or remote rides,
I add an extra tube or two. With this setup, I've not been
stranded once in the last 5 years (roughly 15,000 miles).
Perhaps I've been lucky, but for me a frame pump seems
superfluous and a bit archaic, and I'd rather not have
anything extra hanging on the bike. Of course, YMMV.

--
~_-* ...G/ \G http://www.CycliStats.com CycliStats -
Software for Cyclists

 

[Paul Kopit]

On Wed, 7 Apr 2004 10:26:19 -0400, "John Rees" <[email protected]> wrote:

>So CO2 has a higher mass than either Nitrogen (most of our
>air) and O2. How do these big molecules manage to sneak out
>of your tube faster than air?

CO2 is a solvent. Actually, a pretty good organic solvent.
It's used to extract flavors and fragrances.

 

[Bill]

I' ve used them for years. The smaller CO2 will fill a 23c road tire plenty
full to finish a ride. It will lose pressure overnight and will need to be
pumped the next day. They are a quick and convenient alternate to a pump
and you can carry several CO2s if necessary.
"Guy Goldich" <[email protected]> wrote in message
news[email protected]...
> I've used a Zefal HPX frame pump for the last 15 years or
> so without problems. I usually carry 2 inner tubes and a
> patch kit.
>
> However, at my local bike shop, my eye has been straying
> over to the CO2 inflators. Most of my rides are between 20
> and 40 miles. I've heard that since CO2 is a smaller
> molecule, tires lose air quicker.What has been people's
> experience with them? Viable alternative? Weight &
> reliability?

 

[Joe Faustnospam]

On Tue, 6 Apr 2004 18:56:20 -0400, "Guy Goldich" <[email protected]>
wrote:

>I've used a Zefal HPX frame pump for the last 15 years or
>so without problems. I usually carry 2 inner tubes and a
>patch kit.
>
>However, at my local bike shop, my eye has been straying
>over to the CO2 inflators. Most of my rides are between 20
>and 40 miles. I've heard that since CO2 is a smaller
>molecule, tires lose air quicker.What has been people's
>experience with them? Viable alternative? Weight &
>reliability?
>
A few months back I purchased the Innovations Slim Jim CO2
hybrid inflator:

http://tinyurl.com/29oyd

Fortunately I have mounting pegs under my down tube and
mounted the Slim Jim just forward of the BB. Haven't had a
chance to use it, but I like the idea of having both a small
pump and inflator mounted out of the way.

Joe