[audioholic]

Those bridgestones on the Crysta develop cracks if they are deflated within a short time. My dad had a tyre blow out after driving less than 1km with a flat tyre and the tyre got shredded. So definitely not a good way to swap air by first pulling out all the air from all tyres and then inflating them one by one.

[Toni]

Originally Posted by Mr.Boss

Best solution is to deflate and fill Nitrogen during wheel balancing, where the wheel is off the vehicle without any load.

Yes, this is the best way to deflate and fill Normal air or Nitrogen.

Of course there will be some damage to the tire if they are deflated with the full load of the tyre.

[Dibyendu Bose]

Saw in a blog recently that the TPMS sensors get damaged if the tyres are fully deflated. Do not know whether it’s true but it is best avoided.

To my mind, an in between practice may be to top up with Nitrogen whenever the air pressure goes down. That way you will be improving the percentage of N2 over the years and while you will not be perfect on this aspect, directionally the trend line will be constantly improving….and after a few years the percentage of N2 in the tyre air will be significantly higher than normal air

[ais]

Originally Posted by SS80

Is there a real-world difference between the two air-filling options? I mean a major portion of our normal air is nitrogen. I also highly doubt if a petrol bunk machine can extract pure nitrogen from the air. May be possible in a lab, but not at this scale and place.

There is absolutely a real world difference.

I've gone through the posts and links above and disagree that it's a placebo effect or myths.

These are the differences-

1. Most important is that the tyre pressure remains steady for a few weeks. Changes are mostly due to change in weather. I have TPMS in both my cars, and a digital pressure guage. Also, I maintain pressure in my performance Polo right down to 1/10th PSI. So I know!

2. Pressure changes due to driving are certainly lesser than normal air.

3. The ride does feel softer, though I dont know why, but its probably because nitrogen is less dense than oxygen, so more pliable.

4. Nitrogen is an inert gas. The pumps supply it from bottled nitrogen (just checked- I am at Indian Oil pump, Bandra, as I type this). So the nitrogen is 100% pure and dry. This will definitely extend the life of whichever parts come in contact with it compared to air.

I would not think of reverting back to air.

[StrykerEV05]

I have a slightly unique use case with Nitrogen

I have a Nexon EV so I don't visit petrol pumps for fuel. Due to this almost 80-90% of the staff at the pumps used to make faces while filling free air, besides that even I used to feel a slight guilt. I was tipping them 20 rupees on every visit because of this.

Turns out the same pump had Nitrogen filling service for Rs 20. So i invested Rs 100/200 (Don't remember) for once and got Nitrogen filled in all 4 (in a similar method as described by the OP, except for the passengers - The car was empty).
After that on every visit I'm paying 20 for the top up and the top is less frequent than the one with Air. I top up around once a month and the PSI comes down from 34-30 in this duration.

I think I achieved break even in about 3-4 months and have been in the money since then

[Ravi Parwan]

In my humble opinion, most of the benefit you see from filling nitrogen is from the better "dehumidified" air which expands less with lower water vapor content, which gives you more consistent pressure, which also means that the pressure does not change as much with temperature.

As the normal air compressor air has higher moisture (probably since it is a non glamorous machine which has not seen any maintenance or repair of the air filter) it expands more on heating with the tyre being used on the road. the higher pressure means some of it gets lost from the tyre due to the higher differential (when compared to a dry-er air filled tyre)

this also leads to a change in the manner of ride offered by the tyre as well as more air required for refill.

Most of these nitrogen machines have normal compressors (unless they have cylinders, which I have not seen anywhere) but these are less used, due to the usage fees. Plus they are newer so the dehumidifier is probably still working. So you get dry-er air from these machines, which gives you lesser variation in pressure with temperature. This fuels the myth that nitrogen is good for your tires.

most industrial processes accept gases at 95% purity, not 99%. so highly unlikely these dispensers at petrol pumps can generate more pure gas on site. and if they are getting it from some supplier, it would not be more than 95%.

so 78% (normal air) versus 95%(best case scenario- bottled air). Hard to fathom if any benefit can be derived from such usage. Most likely it is the benefit from dry-er air that is attributed to nitrogen.

[fhdowntheline]

I have been a nitrogen user for over a decade now and my cars have been checked/refilled once every 15 days on an average. It may be placebo or whatever, but I have had less wear and tear and a more even tread wear out as well. Also the tyres do not overinflate during highway runs. Maybe a 38 or so over 36 (filled) on a typical day trip. So I'd say it works.

[Small Bot]

Without getting into the regular air vs nitrogen debate, since it's not time for me to rotate the tyres (my car is just about 10 months old), I just keep topping up the tyres (which came with regular air) every month with nitrogen. I assume that within the next year or so, it will all be nitrogen instead of air if I keep doing this.

For the old i20 Active, I remember that we went to a tyre shop, asked the car to be lifted around two feet with their hydraulic lift so that there was no load on the tyres, and then deflated and reinflated with nitrogen. The same with the old i10. This worked perfectly.

[Jeroen]

Originally Posted by ais

1. Most important is that the tyre pressure remains steady for a few weeks. Changes are mostly due to weather changes. I have TPMS in both my cars and a digital pressure gauge. Also, I maintain pressure in my performance Polo right down to 1/10th PSI. So I know!

A couple of basics on normal air filling and nitrogen filling. Contrary to popular belief on the internet, when it comes to pressure fluctuations due to changes in temperature, air and nitrogen behave almost identically. It is basic physics and the internet can't change that. (At least that is what I think/have been taught).

In practice, it means that a tyre filled with air or nitrogen will increase or decrease pressure in a nearly identical way due to changes in ambient temperature. They just follow the basic gas laws. If memory serves me right I think the difference is less than 0,1%.

When it comes to leaking of air/nitrogen, on a tyre two main reasons can cause these leaks. (apart from punctures and so on)

Rubber tyres permeate the air. So air molecules can make their way, very slowly, through your tire. Nitrogen molecules do so too!!! Just a bit slower than air molecules, about 40% slower.

These days modern tires are made with a special inlay on the inner layer of a tire, so permeation is a lot less. It's always there, but these days it is really small. There is as far as I know legislation in many countries that regulates how thick this layer needs to be. I am not sure if it applies to tyres in India.

Various consumer organisations around the world have looked into this. On average, they found only about 1.3 PSI less over an entire year,

The other possible problem is how well the tyre seals on the rim. This is, by a long shot, a much larger area of concern for most of us car owners. If you need to fill up all your tyres every few weeks, it is never due to permeation, always due to a problem with the sealing of the tire/rim. Or incorrectly fitted items, such as valve stems or TPMS sensors.

Very often this can be solved by removing the tyre, cleaning the rim thoroughly refitting the tire and balancing it.

But then again, adding a bit of air is much quicker and cheaper of course. Also, regardless of whether you have TPMS, it is good practice to check the pressure in your tyres now and then. (And don't forget the spare!)

I would be very interested to learn a bit more about a pressure gauge that can read with 0,1PSI accuracy. Just because your pressure gauge shows values with 1/10th increments on its digital display does not mean it is accurate to 1/10th of a psi. I can almost guarantee it is not. It would have to be a pretty accurate pressure gauge and it would require a lot of calibration too!

I am not quite sure why you would want to measure air pressure at 1/10 psi either. I don't think car or tyre manufacturers specify tyre pressures at that level.

I will say this though: The biggest problem with pressure in tyres, be it air or nitrogen filled is the accuracy of the gauge used. Very few, if any pressure gauges get calibrated regularly. I have experience in my own shop with how quickly, even high-quality pressure gauges, become in accurate. I just buy a new one every 12-18 months. The only way to ensure I get good, sort of half-decent, accuracy. One simple check is to use two different gauges and see if they indicate differently.

Originally Posted by ais

2. Pressure changes due to driving are certainly lesser than normal air.

Maybe according to you, but not according to physics. There could be other reasons for your observation of course. For the average driver, there’s no discernible difference between driving with nitrogen-filled and air-filled tires

Originally Posted by ais

3. The ride does feel softer, though I dont know why, but its probably because nitrogen is less dense than oxygen, so more pliable.

The molecular weight of pure nitrogen is 3% less of typical air.
Again, not due to physics. There must be something else to cause this observation of yours.

Originally Posted by ais

4. Nitrogen is an inert gas. The pumps supply it from bottled nitrogen (just checked- I am at Indian Oil pump, Bandra, as I type this). So the nitrogen is 100% pure and dry. This will definitely extend the life of whichever parts come in contact with it compared to air.

I doubt very much that the nitrogen is 100% pure. There are two reasons for this. It is very expensive to produce 100% nitrogen. The other reason is that at a percentage of over 93% nitrogen, oxygen from the outside air starts to migrate back into the tire! Look it up.

Nitrogen for tyres is always somewhere between 93-95% pure.

Originally Posted by ais

I would not think of reverting back to air.

If it makes you happy and comfortable, by all means, keep doing it!

Lastly, if you want to fill your tires with nitrogen, for any effect, because of the effects (mainly slightly slower permeation losses) the tires need to filled and flushed with nitrogen several times over. If you just deflate the tire and fill it up with nitrogen, it is not going to make any difference whatsoever.

Just my 2 cents of insights. It is enormously valuable to debunk all kinds of crap on the internet.


Jeroen

[ais]

Originally Posted by Jeroen

A couple of basics on normal air filling and nitrogen filling.

I'd suggest you use nitrogen in 2 tyres of 1 side and air in the other 2 of the other side. Observe for a couple of months, then kindly update here.

Digital guage- there are many that measure accurately to 1/10th PSI. I use this-

STHIRA® Tyre Pressure Gauge Digital, Tyre Air Pressure Gauge 150 PSI 4 Settings for Car Truck Bicycle with Backlit LCD https://amzn.eu/d/4KnDGWb

It tallies with the Sensairy TPMS.

I keep exactly the same pressure in front tyre and lower in the rear (but same left and right) in my present car- Polo TSI MT. Manufacturers specifications are only a guideline. One has to find the optimal pressure based on load, road surface and climate (lower in summers to compensate for higher expansion and hotter roads compared to winters). For BMW 3 series F30, 31PSI all across with no passenger worked best in Bridgestone RFT in 320d and same and Michelin PS4 in 330i. In Baleno with Apollo Alnac, 29 PSI in winters and 28 PSI in summers works well all around. In Polo, Bilstein B12, with Michelin Primacy 4 30 PSI front and 28.5 PSI rear work best in present whether. As to why such precision is needed, it's about the car feel. I can tell if a tyre pressure is off by 1PSI.

For replacing air with Nitrogen, best is to jack up the tyres one by one, deflate, fill with Nitrogen to 40 PSI, deflate again and fill to 3 PSI higher than desired (in filling, gases heat up). We may still not have 100% nitrogen, but that's good enough given that air was anyway 80% nitrogen.

I'm not an average driver! Also hold a distinction in Physics.

[Jeroen]

Originally Posted by ais

Digital guage- there are many that measure accurately to 1/10th PSI. I use this-

STHIRA® Tyre Pressure Gauge Digital, Tyre Air Pressure Gauge 150 PSI 4 Settings for Car Truck Bicycle with Backlit LCD https://amzn.eu/d/4KnDGWb

Not to put too fine a point on it: but the pressure gauge you refer to says:

Precisely Measurement: Digital display for clear and accurate readings, with high precision in +/-1.5psi. 4 units with range: 0-150PSI

That is not the same as a 1/10th psi accuracy. In fact, they don't even quantify the accuracy. As I suspected you (and these guys) are mixing up accuracy and reading resolution, which are two completely different things.

You also don't know how accurate this thing is after six months of use. There is a reason that MOT stations in the west, need to replace their tyre pressure gauge every 12 months. And they start with a way better, more robust and more accurate gauge than this thing.

Jeroen

[ais]

Originally Posted by Jeroen

Not to put too fine a point on it: but the pressure gauge you refer to says----
That is not the same as a 1/10th psi accuracy.

So long as the readings correspond with another guage (in my case the Sensairy TPMS), I know both are accurate to 1/10the PSI. For instance, the digital guage reads .6 PSI lower than the Sensairy, but that difference is totally consistent for all 5 tyres in the pressure ranges that refilling and corrections are made at the filling station and then at home on cold tyres 25-35 PSI. The Sensairy TPMS also shows temperature, so we know that a couple of degree rise in a tyre is causing the pressure to rise there.

Similarly, an older digital guage I've used for about 8-10 years in the Baleno (Digicop- no longer available) reads to .5 PSI and corresponds within .5 PSI with that cars Sensairy TPMS. Therefore, it is accurate to .5 PSI. It's going strong, so I'll change it only when there is a discrepancy, not because MOT stations in the west do so.

Again, I suggest you try these things personally, observe over time, and then provide us feedback from such experience.

Before digital guages arrived, I was using PCL pen type guages since I've been driving- about 40 years. Still have one.

Here is a screenshot of the Sensairy TPMS readings and matching of pressures. This was in cold tyres in peak summers.

[Redex]

Paying to fill your tyres with nitrogen is a SCAM !!!!!

Just consider these points. Assuming an average tyre filled to 2 bar (approx 30 psi). The flat tyre will contain 20ltrs of air.

1. Even if you fill with nitrogen, you are starting with a tyre full of air containing 22% oxygen, co2, other gases and a fraction of a gram of water vapour.

2. Even inflated with 60 litres of nitrogen, on top of the 20ltrs of air already in a flat tyre, to reach 2 bar it will stil contain 5.5% oxygen, co2, other gases and a fraction of a gram of water vapour.

3. Weight saved if you could fill with 100% nitrogen would be 1.5gms for each wheel !!!

4. Nitrogen "molecules" are only 2.7% larger than oxygen "molecules". Using normal air the tyre will only contain about 21% oxygen anyway.

5. The type of gas used to fill the tyre will make absolutely no difference to the ride dynamics of the tyre. What matters is the "pressure". Unless of course Pascal and Boyle are wrong and all our calculations of pressure and temperature in Applied Physics are wrong.

6. Hot lap testing has shown that a nitrogen filled tyre starting at 20c and finishing at 40c is only 1/10 of a psi lower than using normal air.

7. A 1 year study on 31 pairs of nitrogen vs air filled tyres at 31psi (approx 2.1 bar) has shown nitrogen filled lost 0.042 psi/week and air filled lost 0.067 psi/week.

8. If you believe that using nitrogen means you don't have to check your tyre pressure as often as using air, you are deluded. Tyre pressure must be checked at least every month, ideally every 2 weeks, and more often for high mileage drivers.
I check my pressures weekly as I drive about 900 kms a week cruising at 110/120 kmh for 80% of the journey. If you extend the time between tyre pressure checking just because you fill with nitrogen you are endangering yourself and every other road user.

9. Use any gas you like (within reason). The MOST IMPORTANT thing to do is CHECK TYRE PRESSURES REGULARLY.

Any perceived effects, felt or otherwise, are just the placebo effect kicking in. As they say "a fool and their money are easily parted"

Sorry if this offends anyone just want to debunk the nitrogen myth. They are my opinions as a vehicle mechanic and trained tyre fitter (also Qualified in Applied Physics).

While checking tyre pressure also check the condition.

Drive safe.

Regards Neil

[ais]

Originally Posted by Redex

Paying to fill your tyres with nitrogen is a SCAM !!!!!

Just consider these points. Assuming an average tyre filled to 2 bar (approx 30 psi). The flat tyre will contain 20ltrs of air.

1. Even if you fill with nitrogen, you are starting with a tyre full of air containing 22% oxygen, co2, other gases and a fraction of a gram of water vapour.

This is getting 'interesting'.

Where have "weight" and "litres" come from now?!!!. What's the relevance? Even my distinction in Physics is failing me now! And how I dread the Moles from Chemistry.

Few key points here-

1. Nitrogen is free in India. Once upon a time it used to cost some Rs.10-20/- per tyre, but nothing since quite a few years.

2. The roads in India are very different from UK. On baby buttock smooth roads, I'd agree that it may be impossible to distinguish the ride quality between air and nitrogen. Here in India, the difference is easily noticable. Not sure about the average driver. But couple of months back, I started hearing a mild "pach pach" cyclical sound that matched frequency with car speed even while coasting, so I guessed its from the tyres. Seemed to come from the right rear. On the car lift at VW workshop, the mechanic and I spun each wheel, and I aligned the edges of the tyre to a dot type light (like a modem LED) behind. It turned out that the rear leight tyre was wobbling slightly (alloy wheel was fine). Then at the tyre vendor (Saifee), the wheel was checked in a balancing machine. The defect was debated at length between the Michelin representative and me before the vendor. Finally, the Michelin official put that tyre up for replacement as soon as new stock arrives. The tyre was also swapped to the front right where its making less noise. Higher pressure also reduces the noise.

Point is that some drivers are that sensitive to what's going on with the car. Others may not be. So air, nitrogen or any other fancy gas wouldn't matter.

3. We have TPMS (OEM or aftermarket) so leave aside checking the tyre pressure weekly, it gets checked in every ride. Any fall below the limit we set rings an alarm. Mine is set at 26 PSI. For cars without TPMS, yes, a weekly check at least, and before each highway ride is ideal.

[Redex]

Hi,
don't understand your first comment, what do you mean ? "Where have weight and litres come from". Gases have weight. Fitted tyres have volume measured in litres. The SI system uses Mass for weight and Moles for quantity. It is easier for non-technical people to understand Grams and Litres as opposed to Mass and Moles. Do you buy 55.55 Moles of water or 1 ltr of water when you go shopping.
Likewise do you buy 9.81 Newton's of rice or 1kg of rice ?
Key point 1.
The U.K. has plenty of bad roads, the exceptions are some major town/city roads and most expressways. Most other local roads are very poorly maintained, even after filling 1.4 to 1.7 million holes per year. The Royal Automobile Club says that potholes are now one of the major reasons for breakdowns in the U.K. 57% of British drivers say they have hit at least one pothole a week over the last twelve months, with the impact causing damage to over 13 million cars. In the last 12 months 2.7 million cars were forced off the road to undergo repairs following pothole damage.
I am getting tired of the comment that Indian road conditions are unique, they are not. Nor are the weather conditions. The only real difference is the quality of driving and driver education/testing and lack of compliance with road rules. Just look at the death rate compared with the Western World.

I base my comments with experience of driving cars and riding two wheelers for 8 months of the year in the U.K and the remaining 4 months in India.
I have been driving/riding in India over 17 years, totalling nearly 5 years on Indian roads. How long have you been driving in the U.K. ?

Quote :
There is no evidence in the entire gamut of applied physics or chemistry that any particular gas is going to produce a tangible benefit to the dynamic performance of a tyre, or reduce the failures. Cornering, braking, steering, rolling resistance, ride quality - they’re all irrelevant to which gas you use.

As a vehicle mechanic aged 67 I am fully aware of changes in a vehicles ride/performance/sounds etc. It's all part of the process of diagnostics when servicing/repairing any vehicle. I have never experienced anything at all to justify filling with nitrogen. Don't forget there are multi millions of vehicles on the road without any form of TPMS.
If filling with nitrogen is free carry on, it's not doing any harm apart from damaging the environment, but please don't fool yourself into thinking that you are getting any benefit. The Laws of Physics "PROVE" that there is no quantifiable benefit.
We haven't even begun to discuss the detrimental global warming effect of the carbon footprint of producing nitrogen !!!