"Paul Calman" wrote ...
> I would probably keep the regulator dismounted
> and use a type of tank with a cap, like on an O2
> bottle, I wouldn't want that sucker busting off a
> regulator while in a collision.

CO2 regulators are a little different in that you are supposed to replace
the plastic washer in the connector every time you remove the regulator from
the tank... The internal pressure in the tank varies from 700-1800 psi while
there is still liquid CO2 in the tank... There have been people who have had
the pressure release blow off while in a car and it has been described as
loud and startling, but not a serious safety issue unless you kept the
windows closed and allowed the CO2 concentration to get up high enough that
it might cause breathing difficulties... It is loud and slow enough that you
have plenty of warning and time to roll down the windows and stop the car...

> What is the expansion coefficent of CO2?

From what I've read, it is basically the same as air...

> we used Nitrogen in race car tires because
> it doesn't change the tire pressure when it
> heats up as much as air.

Nitrogen is also used for Guinness beer kegs... All other beer kegs use CO2
for pumping the beer out... Although nitrogen is a better gas for tires, you
have the same limitations with it that you do with air from the standpoint
of capacity... A nitrogen tank will still be a compressed gas in the tank
and not a liquid, so assuming a 3000 psi tank, you're not any better off
than just rigging a scuba tank for an alternate gas supply... CO2 gives you
twice the air supply in the same physical size tank since it is a liquid...
The tank is not completely filled with CO2 since you need to leave a fairly
good size expansion space in case the tank heats up too much... You don't
want the pressure release to be dumping all your CO2...

Since I'm located in the Houston area, we don't have rocks to crawl over, so
we don't have to lower our tire pressure as much as the rock crawlers... I
run my 31x10.50s rather high while on the road, but offroad, I'll drop them
down to around 20 psi... Offroad around here means mud and some sand, but
the sand is usually packed so tight that you don't even need to air down for
it...

 

"Paul Calman" wrote ...
> I would probably keep the regulator dismounted
> and use a type of tank with a cap, like on an O2
> bottle, I wouldn't want that sucker busting off a
> regulator while in a collision.

CO2 regulators are a little different in that you are supposed to replace
the plastic washer in the connector every time you remove the regulator from
the tank... The internal pressure in the tank varies from 700-1800 psi while
there is still liquid CO2 in the tank... There have been people who have had
the pressure release blow off while in a car and it has been described as
loud and startling, but not a serious safety issue unless you kept the
windows closed and allowed the CO2 concentration to get up high enough that
it might cause breathing difficulties... It is loud and slow enough that you
have plenty of warning and time to roll down the windows and stop the car...

> What is the expansion coefficent of CO2?

From what I've read, it is basically the same as air...

> we used Nitrogen in race car tires because
> it doesn't change the tire pressure when it
> heats up as much as air.

Nitrogen is also used for Guinness beer kegs... All other beer kegs use CO2
for pumping the beer out... Although nitrogen is a better gas for tires, you
have the same limitations with it that you do with air from the standpoint
of capacity... A nitrogen tank will still be a compressed gas in the tank
and not a liquid, so assuming a 3000 psi tank, you're not any better off
than just rigging a scuba tank for an alternate gas supply... CO2 gives you
twice the air supply in the same physical size tank since it is a liquid...
The tank is not completely filled with CO2 since you need to leave a fairly
good size expansion space in case the tank heats up too much... You don't
want the pressure release to be dumping all your CO2...

Since I'm located in the Houston area, we don't have rocks to crawl over, so
we don't have to lower our tire pressure as much as the rock crawlers... I
run my 31x10.50s rather high while on the road, but offroad, I'll drop them
down to around 20 psi... Offroad around here means mud and some sand, but
the sand is usually packed so tight that you don't even need to air down for
it...

 

"Paul Calman" wrote ...
> I would probably keep the regulator dismounted
> and use a type of tank with a cap, like on an O2
> bottle, I wouldn't want that sucker busting off a
> regulator while in a collision.

CO2 regulators are a little different in that you are supposed to replace
the plastic washer in the connector every time you remove the regulator from
the tank... The internal pressure in the tank varies from 700-1800 psi while
there is still liquid CO2 in the tank... There have been people who have had
the pressure release blow off while in a car and it has been described as
loud and startling, but not a serious safety issue unless you kept the
windows closed and allowed the CO2 concentration to get up high enough that
it might cause breathing difficulties... It is loud and slow enough that you
have plenty of warning and time to roll down the windows and stop the car...

> What is the expansion coefficent of CO2?

From what I've read, it is basically the same as air...

> we used Nitrogen in race car tires because
> it doesn't change the tire pressure when it
> heats up as much as air.

Nitrogen is also used for Guinness beer kegs... All other beer kegs use CO2
for pumping the beer out... Although nitrogen is a better gas for tires, you
have the same limitations with it that you do with air from the standpoint
of capacity... A nitrogen tank will still be a compressed gas in the tank
and not a liquid, so assuming a 3000 psi tank, you're not any better off
than just rigging a scuba tank for an alternate gas supply... CO2 gives you
twice the air supply in the same physical size tank since it is a liquid...
The tank is not completely filled with CO2 since you need to leave a fairly
good size expansion space in case the tank heats up too much... You don't
want the pressure release to be dumping all your CO2...

Since I'm located in the Houston area, we don't have rocks to crawl over, so
we don't have to lower our tire pressure as much as the rock crawlers... I
run my 31x10.50s rather high while on the road, but offroad, I'll drop them
down to around 20 psi... Offroad around here means mud and some sand, but
the sand is usually packed so tight that you don't even need to air down for
it...

 

On Fri, 17 Oct 2003 15:49:32 -0700, "Paul Calman" <spam@trap.com> wrote:


>What is the expansion coefficent of CO2? we used Nitrogen in race car tires
>because it doesn't change the tire pressure when it heats up as much as air.
>This might be worth another experiment, measure temp variation hot and cold,
>say when you have them down for crawling and the temp goes way up after ten
>miles or so from sidewall flex.

I've been running CO2 in my tires for years without a problem. As an experiment
I filled two tires with CO2 and 2 tires with regular air, carefully checked the
air pressure to make sure each tire read the same, and then ran them in 100 F
weather on the highway at 75 mph for 2 hours. At the end I checked the air
pressure and it was the same for all the tires, just a few PSI higher.

http://www.monograms-inc.com/jeep/co2tire.htm

Dean

 

On Fri, 17 Oct 2003 15:49:32 -0700, "Paul Calman" <spam@trap.com> wrote:


>What is the expansion coefficent of CO2? we used Nitrogen in race car tires
>because it doesn't change the tire pressure when it heats up as much as air.
>This might be worth another experiment, measure temp variation hot and cold,
>say when you have them down for crawling and the temp goes way up after ten
>miles or so from sidewall flex.

I've been running CO2 in my tires for years without a problem. As an experiment
I filled two tires with CO2 and 2 tires with regular air, carefully checked the
air pressure to make sure each tire read the same, and then ran them in 100 F
weather on the highway at 75 mph for 2 hours. At the end I checked the air
pressure and it was the same for all the tires, just a few PSI higher.

http://www.monograms-inc.com/jeep/co2tire.htm

Dean

 

On Fri, 17 Oct 2003 15:49:32 -0700, "Paul Calman" <spam@trap.com> wrote:


>What is the expansion coefficent of CO2? we used Nitrogen in race car tires
>because it doesn't change the tire pressure when it heats up as much as air.
>This might be worth another experiment, measure temp variation hot and cold,
>say when you have them down for crawling and the temp goes way up after ten
>miles or so from sidewall flex.

I've been running CO2 in my tires for years without a problem. As an experiment
I filled two tires with CO2 and 2 tires with regular air, carefully checked the
air pressure to make sure each tire read the same, and then ran them in 100 F
weather on the highway at 75 mph for 2 hours. At the end I checked the air
pressure and it was the same for all the tires, just a few PSI higher.

http://www.monograms-inc.com/jeep/co2tire.htm

Dean