CO2 and car tires

[Muzikman]

As some of you know I got a new Xterra last month. Since then I have been reading some Xterra forums. Obviously most of these forums are about off-roading. I was reading a thread about how a group wants to put large bulk CO2 tanks in their trucks so when they are done off-roading they can refill their tires to street pressure.

To me this sounds like a strange idea. As paintballers we know how much CO2 is affected by temperature. If these guys deflate their tires from 35-50psi down to around 18psi which seems to be what they like to run. Then inflate the tires back up to 35-50 psi with CO2. That is replacing about half the air in the tire with CO2. Say you do this 4 times, the amount of normal air in the tire is now a very small fraction.

Does this sound strange to anyone else or is it just me?

[Resurection]

That is a blowout waiting to happen imo. As I recall, the tires will heat up dramatically dependingon the driving they will do after the fill up. Not a scientist, but I think that will have bad effects on the tires.

-Resurection

[NJPaint]

They should just use HPA tanks... Just fill up with air.... As for CO2... I don't think that there will be any serious problems with it. I mean tires heat up, yes, but not enough to have that much of an effect on a tire.

[Muzikman]

I suggested a suba tank...they kinda laughed at me. I am not sure they actually know the difference.

I don't know if it would blow out an off-road tire, but trying to keep the pressure consistant would be a PITA. I mean as it is they tell you to check your tires when they are cold and fill them to the mfg reccomended pressure. If you filled the tires with CO2, not only would the pressure change as soon as you were done filling them (it would be cold when filling because of the quick escape of CO2, and them warm up) but thit would increase a lot just driving down the road.

[68bird]

the owner of the local paintball field has a 20ounce co2 tank with a tire fill nossle on the end that he fills tires up with. hasent had any problems with it.

[Muzikman]

Just because there are no noticable problems doesn't mean it is good for your tire. Incorrect tire pressure can cause problems on cars. But also, a 20 oz tank isn't going to fill a car tire full enough to worry about it.

I also know from my mtb experiance that you should not use co2 to fill bike tires. I figured the same would go for car tires.

[Commissar_Loki]

Well, palmer makes a tire stabilizer of sorts. And according to him, CO2 is extremly stable at less than 150 PSI... Thus why he uses it for his markers and such I would assume.


-Butch

[CKY_Alliance]

I know when we used to race we would fill the tires with nitrogen becasue it is more consistent and doesnt expand and contract as much. As for c02 its as bad if not worse then air at expanding and contracting im pretty sure its worse so deff not a good idea in my opinion.Ask if they mean nitrogen?

WTF~umm what happened to post above me the thread hijack..it was there then gone o my o my..i guess he edited..

[Army]

Pure nitrogen has huge molecules compared to regular air, so it doesn't escape through the membranes of modern synthetic rubber tires. Pure nitrogen will maintain tire pressure for a long long time. NASCAR and Top-Fuel cars use nitrogen filled tires to keep pressures more nominal than air.

Co2 in a tire is asking for a burst at the worst, and widely fluctuating pressures at best.

[Hairball]

Co2 in a tire is asking for a burst at the worst, and widely fluctuating pressures at best.

That sounds like an excellent deal. Err..

[SlartyBartFast]

Pure nitrogen has huge molecules compared to regular air, .

Uhm, you do know that "regular air" is 80% nitrogen. Right?

I don't think the nitrogen fill stations are necessary for regular cars and the benefit are probably mostly hype. Pure nitrogen fills probably belong with race cars and aircraft. Applications that see huge temperature and performance extremes.

As for CO2, don't know what the big danger would be. Under normal use it should be fine, unless someone can point me to an authoratative source.

But for practical purposes, why don't the off-roaders just by a 150psi air tank? Just fill it at the garage before heading out. No need to find CO2 fill stations, or high pressure compressors.

[brianlojeck]

most auto parts catalogs sell on-board compressors, given the safety concerns of off-roading with a co2 or hpa tank in the car I'd rather just carry a compressor...

[SlartyBartFast]

most auto parts catalogs sell on-board compressors, given the safety concerns of off-roading with a co2 or hpa tank in the car I'd rather just carry a compressor...

That's so obvious I feel stupid for not saying it myself.

The only drawback is the time the cheaper compressors take to inflate a tire. You'd need a good quality and capacity compressor to inflate a number of off-road tires.

[mcdkid]

i think we had a thread on this before that tom made???...

anyway, it sounds like a reasonable last resort.

[PyRo]

It took one of those cigerette lighter compressors a good 20 minutes to fill up the tire in my camaro which was flat. So figure it's going to take about 20 minutes on a 33in tire to raise it from 18 to 33. That's an hour and twenty minutes to fill your tires. If you have a standard 135psi big air tank onboard it might raise the pressure up to 25 or so, enough that it's streetable and can make it to a real compressor.

The only options left are high pressure tanks or a belt driven compressor. A lot of guys like to play with old AC pumps and make compressors strong enough to power air tools. I'm guessing no one is going to want to do this on their new Xterra though. So it's down to HPA, like you said rig up a SCUBA tank. If they don't want to listen let them play with Co2 and have treadwear/blowout problems. You can laugh at them 10,000 miles down the road when they're dumping $800 on tires and yours are fine.