Nitrogen in Tyres (Tires)

TheSkyIsFalling

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How much do you currently pay attention to tire pressures as they warm? What PSI range do you try to keep the tire in when driving?

If you don't have answers to both of these, then nitrogen is probably a waste of your time and money. If you obsess over these things and want to eliminate some variance, then it will help.

I use strictly air

I can say living in a snow climate. Where it’s not uncommon to see -20C temps. Generally it’s about 5psi difference.


But when there are days that start out at -28C and by 2pm it’s +10C. I can see 8-10psi difference there


I will say this about nitrogen. My friend bought a brand new car with nitrogen filled from the factory. She got a brand new set of rims and tires for winter. (Air)

She stores her tires at my place. I can say that over the course of 5 years. Her nitrogen filled tires has lost about 2 psi.

Her winter air filled tires loses anywhere from 5-15psi each time over storage.

I check the tire pressure everytime before she puts her tires on.

No tire has ever had a puncture
 

CPB

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Nitrogen is nice, problem is I never have a tank of it trackside to adjust pressures. Air pump is way too convenient. Having the PSI I want is more important to me than the variance.
 
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GotWake

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Nitrogen is nice, problem is I never have a tank of it trackside to adjust pressures. Air pump is way to convenient. Having the PSI I want is more important to me than the variance.
And if you aren’t keeping the proper pressures, you will wear your tires out early. If you are having to run by the dealership to get nitrogen added, most people aren’t going to do it as often as they should.
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Outside of aviation and racing, I just don’t see much of an advantage for the everyday car.


Consumer Reports conducted a study comparing nitrogen versus air loss in tires to determine if this benefit of nitrogen was worth the extra cost. They used 31 pairs of various tire models, filled one tire of each pair to 30 psi with air and the other to the same pressure with nitrogen, then left them outside for a year. At the end of the year, they found that all tires lost pressure. The average pressure loss with air was 3.5 psi; with nitrogen the average loss was 2.2 psi – a difference of only 1.3 psi over a year.
 
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nicholat

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If you had a tub inside your tire I could see it filled with a higher % of nitrogen. By the way do not racing tires have a tub/tire inside of a tire type construction. In the old days car tire did also have tub inside there tire like your bicycle.
 

kwthom

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unless you put your tires under vacuum before replacing with nitrogen you are only diluting it to begin with.
How much atmosphere do you think can be removed without pulling the tire off the bead of the rim? :haw:

You would reduce the atmosphere inside the tire, you'll never thoroughly evacuate that space.

I did leak testing of aerospace items...98% purity nitrogen wasn't cheap for a 6K cylinder of it. In order to completely inert the assembly, it was purged & filled three times.
 

poolmon

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In 1987 the FAA issued an Airworthiness Directive (AD) requiring nitrogen (or other inert gas) be used in large aircraft after a 1986 air crash that involved an air filled tire with an overheated brake that spontaneously exploded in the wheel well with adjacent fuel lines. The purpose of requiring nitrogen being to avoid fire/explosion on these stowed tires with hot brakes. Don't see much carry over to our daily drivers. Purge required to allow maximum oxygen content of 5% (vs 21% in air).

AD below:
AIRBUS INDUSTRIE, BOEING, BRITISH AEROSPACE,
 
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wjbertrand

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After a while, even if you initially filled your tires with air, the nitrogen to oxygen ratio will rise above the initial 78% anyway. O2 has a slightly higher permeability through rubber than N2 so over time you will lose proportionately more of the oxygen. The main advantage to nitrogen over air (and probably only important in critical racing situations) is that the process of separating and compressing nitrogen from air makes it extremely dry. It's really the excess moisture in air changing phases from liquid to gas and vice versa that causes more pressure variation, not the air itself. Really dry air would perform exactly the same way as pure nitrogen with respect to pressure variation with temperature. The only noticeable difference might be the need to top air off slightly more often.
 

WGSNewnan

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How much atmosphere do you think can be removed without pulling the tire off the bead of the rim? :haw:

You would reduce the atmosphere inside the tire, you'll never thoroughly evacuate that space.

I did leak testing of aerospace items...98% purity nitrogen wasn't cheap for a 6K cylinder of it. In order to completely inert the assembly, it was purged & filled three times.
we ran bead locks so that was a non issue.
 

ILS27L

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I use and am a fan of using 78% nitrogen in my tires - it’s free too. I don’t change the blinker fluid either.


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What ? The dealer has changed mine 2 times. Said it was regular maintenance. :bang:
 

TurboDriver

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What ? The dealer has changed mine 2 times. Said it was regular maintenance. :bang:
I've had a couple muffler bearings go bad before, it made a hell of a racket!
 

Saussie

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One other consideration is whether you'll have nitrogen readily available to top them off. Otherwise, you'll be diluting them with each top off and introducing moisture. I've never had trouble with regular air fill ups.
100% agree with this. Won't find it at your local service station to top up.
If I'm right though, back in the day, a UK petrol station charged money to use the air compressor to fill the tyres. Unsure if they still do this, but guess if you're paying for inflation anyway, maybe it's no big deal either way.
Air is free round my way, so I don't bother, as I can pump my tires up until my heart is content or I get a puncture.
 

TheSkyIsFalling

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100% agree with this. Won't find it at your local service station to top up.
If I'm right though, back in the day, a UK petrol station charged money to use the air compressor to fill the tyres. Unsure if they still do this, but guess if you're paying for inflation anyway, maybe it's no big deal either way.
Air is free round my way, so I don't bother, as I can pump my tires up until my heart is content or I get a puncture.

Back in day here in Canada. Air used to be free at gas stations. I think because most gas stations had a 1-2 bay mechanic station attached so it didn’t take much to give free air. And the gas stations that didn’t have a mechanic bay. Had a compressor to followsuit. But over time as new gas stations were built without mechanic bays and the ones with mechanic bays were closing down. Eventually they started charging for air. 50c to $1 now it’s $1.50
 

Saussie

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Back in day here in Canada. Air used to be free at gas stations. I think because most gas stations had a 1-2 bay mechanic station attached so it didn’t take much to give free air. And the gas stations that didn’t have a mechanic bay. Had a compressor to followsuit. But over time as new gas stations were built without mechanic bays and the ones with mechanic bays were closing down. Eventually they started charging for air. 50c to $1 now it’s $1.50
Incredible!
I have a cigg socket air compressor at home I use to top up should I need it. It's not great, really suits a mountain bike I think or motorbike. Have done a completely flat tyre before, but had to stop halfway to let it cool down, then start again. It might take 20-30min haha (cheap mini air compressor), but gets me out the driveway to the service station.
Guess charging a customer for it pays for the power to run it and the wear and tear on the line and seals.
People used to steal the end sometimes with the press button and gauge, until they made a new automatic air pump, where you set the psi and just connect to the tyre valve and it self inflates.
Rarely see an actual mechanical repair garage now. All fuel only. Some unmanned ones popping up too just operated by card swipe.
 
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BlueV1

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Perhaps of interest as this thread is about tire pressures;

I recently installed an aftermarket TPMS system. First I tested with sensors that screw on in place of the valve caps and then once I was satisfied with the system, I had internal sensors installed. My pressures are always available to look at on the screen.
(Also, I've experienced a few different factory TPMS setups with pressure displays as well in the last few years and have seen the same behaviors that I'm about to describe.)

Temperature differences are definitely part of it. I can start out with 33 PSI when the ambient temp is around 60 degrees F, or if it's already 75 degrees F or so, the PSI readings will be around 35 PSI or 36 PSI.
Either way, I will then drive for a couple of hours at highway speeds and on some twisty mountain roads and the PSI will typically read 38 to 39 PSI. Usually the front tires are a little higher.
This has been a consistent daily pattern with both the "factory/dealer" nitrogen and now regular air since having the sensors installed. Typically a 4-6 PSI increase after driving a couple of hours with ambient temps rising and then back to 33 PSI in the morning.
Also, I change elevations quite a bit throughout the day sometimes. I can be at 650 feet and an hour or so later at 3,700 feet and that might have a little bit to do with my readings at times.

It will be interesting to see what cooler temps reveal.

I would not worry too much about a couple of PSI here or there. The main thing is probably to set your tires to the desired PSI before the sun starts shining on them and be aware that seasonal temperature changes that will affect the PSI values.
If you are going to test nitrogen vs oxygen with 78% nirtogen, make sure all the other factors are identical.
 

poolmon

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Typically a 4-6 PSI increase after driving a couple of hours with ambient temps rising and then back to 33 PSI in the morning.
At Costco's tire shop if you bring in your car to check/add air and tell them the tires are hot (full operating temp) they automatically put in 4 psi more that the door sticker's pressure specification for the vehicle, so this tracks with yours.
 

GernBlanston

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For sure but you forget about the water in the air which results in a greater pressure change with air. This is why race car teams prefer nitrogen.
Yeah, but below 100psi, water vapor behaves like any other gas, and with the small percentage of water vapor in air, it's gonna' be pretty darned close to dry nitrogen expansion-wise. We use nitrogen in the tires of the jets, but it's mostly because it leaks more slowly (supposedly) and there's no corrosion issues on $30,000 wheels.
 

Saussie

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Perhaps of interest as this thread is about tire pressures;

I recently installed an aftermarket TPMS system. First I tested with sensors that screw on in place of the valve caps and then once I was satisfied with the system, I had internal sensors installed. My pressures are always available to look at on the screen.
(Also, I've experienced a few different factory TPMS setups with pressure displays as well in the last few years and have seen the same behaviors that I'm about to describe.)

Temperature differences are definitely part of it. I can start out with 33 PSI when the ambient temp is around 60 degrees F, or if it's already 75 degrees F or so, the PSI readings will be around 35 PSI or 36 PSI.
Either way, I will then drive for a couple of hours at highway speeds and on some twisty mountain roads and the PSI will typically read 38 to 39 PSI. Usually the front tires are a little higher.
This has been a consistent daily pattern with both the "factory/dealer" nitrogen and now regular air since having the sensors installed. Typically a 4-6 PSI increase after driving a couple of hours with ambient temps rising and then back to 33 PSI in the morning.
Also, I change elevations quite a bit throughout the day sometimes. I can be at 650 feet and an hour or so later at 3,700 feet and that might have a little bit to do with my readings at times.

It will be interesting to see what cooler temps reveal.

I would not worry too much about a couple of PSI here or there. The main thing is probably to set your tires to the desired PSI before the sun starts shining on them and be aware that seasonal temperature changes that will affect the PSI values.
If you are going to test nitrogen vs oxygen with 78% nirtogen, make sure all the other factors are identical.
Good way to test and find out.
 

Jammernet

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Well I had the Nitrogen fill done.

I have TPMS so easy to monitor. The pressure still increases as the tyre warms up (seemingly about the same rate as with air) but if anything the change does seem more consistent across the 4 tyres. We will see how it goes as the autumn approaches.
 
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angrypenguin

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I fell for this scam.

Air is 78% nitrogen, sure, that's half of why this is a scam. The other half? All gases follow the ideal gas law. PV = nRT

Any fuel savings achieved (arguable at best) with nitrogen are also wiped completely off when you have to drive to get them topped up/filled up in the winter.
 

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