Nitrogen fill for tires?

[Camper63]

I work in a trucking company shop and we do the Nitrogen in the tires when we get new trucks. We still have tire blow-outs from picking up things on the road. I only have it in my RV because the dealer filled them as they do all of theirs, no charge to customer.
If you don't like having to check all the time a tire monitoring system is the way to go. There are various types out there to choose from.

[Don Juane]

Originally Posted by wolfe10

OVERCOME PHYSICS!

I was about to say the same. I often fill HVAC suspected leaking equipment with nitrogen over night and it looks like it has leaked out due to low pressure in the morning but then by the same time of day I took the last reading, the pressure is back up to what I measured before, assuming no leaks of course.

[plumber64]

In the Plumbing and Heating Profession you always read the installation instructions that come with the equipment. Tire manufacturers post the same thing when giving installers the technical bulletins. It's their tire; do what they say. If not you will have no recourse when it fails.

[SUBVET30]

Theory to practice. Only because I have access to Nitrogen, I just filled my front tires.

Just 2 weeks ago, I inflated my front tires to 120psi with good old air compressor air @t 70 degrees in the shop. I dropped 5 psi because I knew we were driving into 100 degrees + that afternoon. It hit 109 on Highway 12 before we stopped.

When we stopped, the tires read 138psi.

I decided to add balance beads (whole other topic for the haters), and thought I would try Nitrogen. I purged the tires as best you can by inflating to 15psi and deflating. I then inflated to 128psi @ 72 degrees.

I checked them an hour later and the pressure was a touch lower between 127 and 128 psi.

I don’t expect any big temperature changes this weekend, but my experience tells me normal driving will raise tire pressure between 6 and 10psi and we are climbing about 1500 feet.

We are going from Washington to Lake Havasu later this year and that will give me a good indication of any validity to this whole Nitrogen discussion.

On a side note; I did not anticipate the amount of Nitrogen filling this super single front tires would use. Good thing it’s inexpensive.

[TXiceman]

Originally Posted by Don Juane

I was about to say the same. I often fill HVAC suspected leaking equipment with nitrogen over night and it looks like it has leaked out due to low pressure in the morning but then by the same time of day I took the last reading, the pressure is back up to what I measured before, assuming no leaks of course.

The Ideal Gas Laws are what they are, and advertising cannot change them, The three Ideal gas Laws are summarized as follows.


Gas Laws: Overview - Chemistry LibreTexts
Boyle's Law tells us that the volume of gas increases as the pressure decreases. Charles' Law tells us that the volume of gas increases as the temperature increases. And Avogadro's Law tell us that the volume of gas increases as the amount of gas increases. Jan 29, 2023



Ken

[SUBVET30]

Originally Posted by TXiceman

The Ideal Gas Laws are what they are, and advertising cannot change them, The three Ideal gas Laws are summarized as follows.


Gas Laws: Overview - Chemistry LibreTexts
Boyle's Law tells us that the volume of gas increases as the pressure decreases. Charles' Law tells us that the volume of gas increases as the temperature increases. And Avogadro's Law tell us that the volume of gas increases as the amount of gas increases. Jan 29, 2023



Ken

Good morning Ken,

Yes, I do know everyone is referring to basic assumptions of gas laws.

I have worked with so many people that are so much smarter than I am over the years. And they are always so shocked when the basic assumptions of (insert scientific law) don't work like they thought.
Not saying the science is wrong, because we have been taught to "trust the science". But the variables in real world scenarios are often over looked.

Take for instance the post a ways back. There was discussion of a temperature change of like 70 degrees. And according to the science, there should be a 14 percent increase of pressure. Well, I had a roughly 14 percent change in pressure with an increase of 39 degrees.

So, laws are written within a controlled environment. Our tires are not in that controlled environment. Is there any expansion of the tire causing the volume capacity to change? I don't know. I just know my tire pressure increases much more than the science says it should.

Thanks again,

R/Lance

[n2zon]

Originally Posted by SUBVET30

Good morning Ken,

Yes, I do know everyone is referring to basic assumptions of gas laws.

I have worked with so many people that are so much smarter than I am over the years. And they are always so shocked when the basic assumptions of (insert scientific law) don't work like they thought.
Not saying the science is wrong, because we have been taught to "trust the science". But the variables in real world scenarios are often over looked.

Take for instance the post a ways back. There was discussion of a temperature change of like 70 degrees. And according to the science, there should be a 14 percent increase of pressure. Well, I had a roughly 14 percent change in pressure with an increase of 39 degrees.

So, laws are written within a controlled environment. Our tires are not in that controlled environment. Is there any expansion of the tire causing the volume capacity to change? I don't know. I just know my tire pressure increases much more than the science says it should.

Thanks again,

R/Lance

I bet my life on the gas laws when blending breathing mixes and diving them. They work just fine, but you need to look at it holistically.

The combined gas law is PV=nRT, where P is pressure, V is volume, n is the number of gas molecules (basically), R is the gas constant, and T is absolute temperature (that is, counting up from absolute zero).

You have to plug them all in unless one or more are small enough to ignore. (Scuba tanks expand when filled but not enough to be more than a rounding error, for example. On the other hand, the high-volume compressed air tanks used to blow ballast are big enough to gain measurable volume under pressure when full. But they're a *lot* bigger than a scuba tank!)

Tire expansion is limited by the cords in the tire, which are much less flexible than the rubber. How much they increase in volume at different inflation pressures is a great question for Roger Marble, but I suspect it's negligible.

Can you provide actual numbers for pressure and temperature for what you observed? If so, we can at least see if they're close to what the gas laws would predict.

[Tireman9]

Originally Posted by SUBVET30

Theory to practice. Only because I have access to Nitrogen, I just filled my front tires.

Just 2 weeks ago, I inflated my front tires to 120psi with good old air compressor air @t 70 degrees in the shop. I dropped 5 psi because I knew we were driving into 100 degrees + that afternoon. It hit 109 on Highway 12 before we stopped.

When we stopped, the tires read 138psi.

I decided to add balance beads (whole other topic for the haters), and thought I would try Nitrogen. I purged the tires as best you can by inflating to 15psi and deflating. I then inflated to 128psi @ 72 degrees.

I checked them an hour later and the pressure was a touch lower between 127 and 128 psi.

I don’t expect any big temperature changes this weekend, but my experience tells me normal driving will raise tire pressure between 6 and 10psi and we are climbing about 1500 feet.

We are going from Washington to Lake Havasu later this year and that will give me a good indication of any validity to this whole Nitrogen discussion.

On a side note; I did not anticipate the amount of Nitrogen filling this super single front tires would use. Good thing it’s inexpensive.

Tire pressure should be set before the tire is driven. If your weight indicated you should inflate to 125 psi then that is what you should do whether you use Air or N2.
Yes pressure changes as tires heat up and air or N2 both will change as temperature changes.

[Tireman9]

Originally Posted by n2zon

I bet my life on the gas laws when blending breathing mixes and diving them. They work just fine, but you need to look at it holistically.

The combined gas law is PV=nRT, where P is pressure, V is volume, n is the number of gas molecules (basically), R is the gas constant, and T is absolute temperature (that is, counting up from absolute zero).

You have to plug them all in unless one or more are small enough to ignore. (Scuba tanks expand when filled but not enough to be more than a rounding error, for example. On the other hand, the high-volume compressed air tanks used to blow ballast are big enough to gain measurable volume under pressure when full. But they're a *lot* bigger than a scuba tank!)

Tire expansion is limited by the cords in the tire, which are much less flexible than the rubber. How much they increase in volume at different inflation pressures is a great question for Roger Marble, but I suspect it's negligible.

Can you provide actual numbers for pressure and temperature for what you observed? If so, we can at least see if they're close to what the gas laws would predict.

well you dragged me into this so..


Yes my calculation of 2% for 10F change is approximate. A couple of observations. Has the accuracy and repeatability of the pressure gauge been checked? Are the temperatures stated Ambient or from the tire? TPMS temperature readings are not the same as Ambient or the same as found with a hypodermic needle thermocouple which measures the temp. of the tire structure. If someone wants to test the Gas law then I suggest they inflate a tire, measure it's pressure and the Ambient. Then with a change in Ambient of 20 to 30F compare pressure.
No idea how someone could accurately establish the temperature of a tire other than using Ambient or the temperature in a controlled chamber such as an oven.

[RVWheeler]

I want someone to do the following test with a standard TPMS system.
Get a baseline with both front tires inflated with shop air. Drive the rig for a minimum of 30 minutes. Also record the approximate free air temperature.
Then the next day after the tires have returned to their pre drive temperature, inflate one front tire with nitrogen and one with shop air. Then repeat the drive again with the same pre drive pressures, route, time and temperature.
Tell us what the tire pressures were at the beginning, mid point and end of each test.
Sound like a fun experiment?

[NXR]

Originally Posted by RVWheeler

I want someone to do the following test with a standard TPMS system.
Get a baseline with both front tires inflated with shop air. Drive the rig for a minimum of 30 minutes. Also record the approximate free air temperature.
Then the next day after the tires have returned to their pre drive temperature, inflate one front tire with nitrogen and one with shop air. Then repeat the drive again with the same pre drive pressures, route, time and temperature.
Tell us what the tire pressures were at the beginning, mid point and end of each test.
Sound like a fun experiment?

While the results would be interesting there is no real world point to it.

Why? Because tires are designed for and tested with air and perfectly safe to run with air.

While nitrogen can reduce the variation an RV's tires are not spinning up from zero to 170 MPH in less than 30 seconds as they do on a jet that uses nitrogen.

An RV's tires are not spinning up from zero to 150 MPH in less than one revolution as they do when a jet lands.

And an RV's tires are not going from ambient temperature to -30 F in a half hour, staying there for hours, and then going back to ambient in a short period of time when landing as they do on a jet.

As one person noted, nitrogen is cheap. An entire cylinder of nitrogen that would last a month or two was less money than what a car shop charges to fill one car. Nitrogen has to have a 10,000% or more profit margin for them. That's why it's pushed so much.

Ray

[jadatis]

I wrote it before here, but might be lost in the pile of posts.

Recently made a pressure/tirepressure calculator for wet and dry.
Can send it to you in return if you mail me at my hotmail. com adress with username jadatis.
Combine yourselfes, spamm-machines cant this way.

Then you can check acurately, and dont need to rely on rules of tumb

Long ago I wrote an article about that filling with normal air is better then with nitrogen.
So turned it around. Someone known and respected on fora, adviced me not to first give the the alledged advantages of Nitrogen filling, and then demith them. Because then those "advantages" are already set in the mind of the readers as true.

Here it is, try to demith this.

Filling car tires with normal air is better then with Nitrogen.

A. Oxygen, which makes 21% of normal outside air, in volume absorbs more energy to rise a degree in temperature then Nitrogen.
Difference is only 1% , but in selling argument is sometimes mentioned in energy/ mass so Joule/kg.degr. Kelvin and there Nitrogen wins by 13 % . Tires though are filled with a certain volume so that counts .
This selling argument can be de-myth simply by the fact that its untrue.

B. Water in a tire transports the heat more then dry air or Nitrogen-filling ( which is by its production process free of water).
Not for no reason water is used in central heating and cooling system of cars as main substance.
The tire inside will have lower temperature which is better for cooling down the important spots of the tire wich have to keep a low enough temperature to prevent hardening and damage in next bending of those parts.
When incidentally the tire inside gets hotter ( sunshine on tire or severe braking, or high ambient temperature) more water goes over to gas wich highens the pressure inside the tire more then dry gas. Also then more water as gas in tire so even better cooling.
So advantage of water is 2 ways when needed, better cooling and lesser heat production.
Disadvantages of water as oxidation only happen at outside . Tire specialists will confirm that when they remove a tire of the rim , the rim inside the tire is not corroded.

C. When a Truck, transporting flammable substance, is on fire, the little oxygen in a tire will , when exploding ,probably even kill the fire .
In tunnels experiments where done to kill the fire with air current , and it worked, despite the oxygen in it.

D. A normal car tire up to truck tire is not a race-car tire, for which a constant as high as possible contact area, so best grip , is needed to give half a second better round time.
For that reason they are filled with as dry as possible air or Nitrogen.
That this gives low lifetime is not important, and for a normal car tire it is.
Often blowing tires at racing, is seen there as collateral damage, but we don’t want that for normal car tires.

E. A car tire is also not a airplane- tire in which the water can freeze and when landing this can give misbalance , which can lead to tire-failure or accident, when suddenly going from zero to about 200m/h.
The water in a car tire does not freeze that often, and when it does and the car begins do drive , it begins slow and the misbalance is not a big problem . then pretty soon, certainly when on speed the ice is melted to water and problem will be gone.

F. When filled with normal air the user is aware of checking the tires regularly, which takes better care of a saver tire, because regularly filled up to the right pressure and optical checking of the tire .
The illusion that Nitrogen filling makes the tire to loose almost no pressure, which is often exaggerated to 5 times , while in real a poor 2 times and then only in the very beginning, makes the user less caring .
The tire also looses air when hitting pavement so temporary leak between edge of tire and rim, Filling with whatever gas-combination won’t prevent that.
This idea is even stronger when TMPS is used which is often inaccurate , so the user thinks to maintain the right pressure, while really riding with to low pressure for longer time, which can lead to tire damage. Aftermarket sensors for TMPS when screwed on the valve can give leakage trough hole where valve is placed , because of the bending of the valve by centrifugal forces at speed.

G. Filling with normal air is always possible, even with a bicycle- pump, is only to fill up so won’t take that long. When you keep driving with to low pressure , in order to find a place to fill with Nitrogen, you damage your tires. So just fill up with normal outside air, even when the tire is filled with Nitrogen. Then also you don’t need to have the tire refilled with pure Nitrogen by your tire specialist when at home again, not worth the trouble, and normal air is even better then nitrogen because of the water in it.

[Dieselgem]

Originally Posted by buddy110

You have to evacuate all the air first then fill. The actual fill isn't expensive, but the purge process is tricky




I monitor my pressures all the time. On more than one occasion I have had to bleed off excess pressure while driving in the extreme heat, then recheck and often refill in the morning. I'm just a bit lazy and I love the convenience of not hauling out the compressor and filling tires. Perhaps I should just bite the bullet and get an air doubler.

Best way to go no fuss, no mess! I use mine all the time.

[brobox]

Air Doublers can still be found on eBay in the $100. range. One of our forum members picked one up last week, with all the fittings and gauges like new for $119. Still lower than a compressor, and 100% filtered air. Watch daily, they come available often. https://www.ebay.com/itm/28507514611...Bk9SR4rngufIYg

Here's one that slipped through for less than the $20. I paid. He got his for $3.25
https://www.ebay.com/itm/29580926992...Bk9SR7y80-bIYg