Tire fill: Something different in the air
 

I will be trying to attain measureable results from filling the tires with something besides air, or nitrogen.
Since I already tested nitrogen years ago and found no measureable difference from air. Makes sense since air is almost 80% nitrogen. You would expect there to be little difference.

I am going as unair like as possible, while staying with non flammable and non oxidizing gases.
Since summer is coming in New Mexico, a lot of roads have been repaved, making them extra black and there for extra hot. I am going to test cooling gasses on hard working trailer and truck tires.
Possible cooling gasses are any heat pump working fluid or inferred absorber.

I dont plan on it saving a bunch of fuel. I am looking to save tires. At $50 to $80 each not blowing them is pretty economical, not crashing even more so.
My winter test will be aimed at saving some fuel in car tires.

How can I do this? Well I keep inert shielding gasses on tap in pure form to mix on site to feed my welding machine. I have CO2, Argon and Helium. Helium is the most expensive by far. I also have refrigerant, a blend R-404a has caught my attention.
To get the gas into the tire I built a tire gas manifold to unite the welding world, HVAC worlds and bring them to the tire world.

Because I am too cheap to waste gas, even if its $1/lb CO2 doing a bunch of purging I will attach a vacuum pump to the tire manifold. Pumping some of the air out of a tire and then filling will have the same effect as preforming 1 or 2 purges.

First tests will be to make sure any of the gasses used for on road tests dont permeate out at some catastrophic rate.
I already tested this with CO2 and it stays where its put.
Next test will be to fill a small trailer tire with helium and see how fast it leaks compaired to its air filled twin.
Then working up to on road tests with varrious gas mixtures.
Filling a tire with something different and hitting the road, not a good idea.

CO2 seems to like absorbing heat through conduction and absorbing IR. And its not a bad refrigerant, just expensive to employ.
Helium likes to move heat really fast. But is the most expensive by far and the most likely to leak out at a higher rate.
Argon, unlike CO2 and Helium likes to move heat more slowly, much more slowly than air.
R-404a is already a mix. The 2 main ingredients are "canned air" and fire suppressant, both are very good heat movers.

So we know refrigerants are used to transfer heat from one area to another using the compressor some valves and a condenser.
What is your theory , why you can cool a tire with a refrigerant when the heat is not later removed from the refrigerant ?

Or what is your hypothesis with using this gas ?

How worldly of you... :thumbup:


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My theory is that you're going to eventually be on the news after you blow yourself or somebody else up.
There's no reason any of those gases would pull any measurable heat out of your tires any more than the nitrogen would, and it also seems kind of irresponsible to test your theory on the road with no idea how those gases react with the tire material under heat & load, while pulling trailer loads of welding equipment. You could probably keep liquid propane in a tire, buy I doubt that you'd really want to drive around on it

In some related threads, there was talk about the heat capacity of various gases - and there is some considerable difference. I suspect the actual difference in operating temperature would be minimal.

But you haven't told us what you are gauging. That is, what is the thing you are measuring to see if there is a difference. How does that relate to things?

But good luck with the experiment.

How differently do these gases expand when heated?

Perhaps I can answer that.

Not much differently. Pretty much all gases at the temperatures and pressure we encounter behave close to the Ideal Gas Law: PV=nRT.

Measurements will be looking for swings in pressure with temperature.
This will be part of the non road test, fill the tire at night to a set pressure, lay it down on the ground where the sun will hit it, let it get good and hot to simulate being driven and check pressure again. I am not expecting much to happen.
The result I am looking for in the cooling test for the tread package to run cooler. Tread slightly cooler, side wall and rim, slightly warmer.
If the complex gasses stay in the tire longer that would be nice too, (the idea behind stayfill).


Did you read the post?
There is an entire pre-onroad phase to this.
I know the gases I am going to test have been used on road or track before.
A company called stayfill sell a fluorocarbon to fill vehicle tires, likely HFC-125 (fire suppressant), R-134a, or "canned air" aka R-143.
Plus how is fire suppressant going to blow up?
You spray into a room full of fire and it goes out, if that's not a definitive test than I dont know what is.
An R-404a mixture was used in F1. Do you think if it were going to blow up they would use it?
No of course not :rolleyes: .

I'm interested in the results of this, but uninterested in the sense that the results won't amount to any practical application.

The various gasses are infinitely more expensive than (free) air, and will not have significantly better operating properties.

The only way a different gas could keep the tires cooler is to more readily absorb heat, and then transfer it to the wheel. Heat conduction is the property of the gas that would be important here, and the conduction rate can be looked up for the various gasses.

That said, helium would be more dangerous since it will leak out rapidly, requiring a pressure check before each trip.

Further, each time you check the tire pressure, you loose a little bit of pressure. I wouldn't be surprised if you loose 0.5 psi each time you check a trailer tire. This, along with the other variables of heat expansion and the tire just loosing gas will muddy the results of the test, since these variables aren't tightly controlled.

I know that is a lot of negative talk about the experiment, but I'm still curious to read the results, and I think it's great that Oil Pan has the motivation to take on such a test and share the results with everyone. :thumbup:

i'm in for the results. good luck.
maybe have wireless psi/temp instruments IN the tires. can't lose pressure that way.