[Spitfire]

Originally Posted by Spitfire

My comment was on whether a miss aligned wheel make more noise then a non aligned one.

Correction: My comment was on whether a miss aligned wheel will make more noise then an aligned one.

Originally Posted by kaushik_s

Can any of the people who are claiming about less tire noise with nitrogen put some logic behind it?

OYE!! you are in queue. I asked the question first

[anupmathur]

Originally Posted by Spitfire

Correction: My comment was on whether a miss aligned wheel will make more noise then an aligned one.

OYE!! you are in queue. I asked the question first

When Nitrogen gets into the head, very heady things begin to happen, LOL!

[kaushik_s]

Originally Posted by Spitfire

OYE!! you are in queue. I asked the question first

OK, anyone else wanna know then please stand in the queue . Even google God is not helping me much in finding the answer.

[71Convertible]

Originally Posted by alpha1

You know this reminds me of the everlasting argument audiophiles have about "snake oil" items like power conditioners and gold/silver cables etc. Which can bring in a "perceived" level of improvement in audio quality.

Another incident that comes to my mind is about the Blues/Rock guitar playing circles. There is this great musician - Eric Johnson, makes lovely music. However, he is extremely quirky.
The grapevine says he gets his overdrive pedal painted specifically in his preferred color, because he feels that brings the tone to life better than other color.



... oops, I know many ppl here wouldn't be able to gauge what I am saying ... but still

Exactly... same effect as lifting your speaker cables on porcelain stand-offs, or directional cables ...

ha... ha...

[71Convertible]

BTW, for claims of N2 diffusing slower a few things to consider:

1. Actually, Nitrogen has lower Molar Mass than Oxygen (~14 vs. 16gms/mol). According to Graham's Laws of Effusion and Diffusion, Nitrogen will effuse or diffuse faster than O2.

([COLOR=#800000] "The relative rates at which two gases under identical conditions of temperature and pressure will diffuse vary inversely as the square roots of the molecular masses of the gases." It shows us that, at equal pressure and temperature, less massive gases will diffuse more rapidly than more massive gases.)
[/COLOR]
One of the advantages of tubeless tires is that when punctured it has a slower rate of air loss and can be driven safely longer distance. Theoretically, a tire filled with pure N2 would lose pressure under this condition faster than one with a mix of O2 and N2. (In reality, diff would not be material).

2. The purity of N2 created by the N2 generators commercially used is not 100%, but is closer to 95%.

3. I believe the molecular size of water H2O is actually smaller than N2. So, by the diffusion argument, most of the H20 should diffuse first (at least until the partial pressure of H2O on both sides of the membrane (tire wall) are equalized.

4. Most of the benefits of N2 in tires have been in racing, commercial, and high temp usages where wheel corrosion is a bigger issue. When was the last time you had today's car alloys see corrosion as the failure mode?

[watashi75]

Just to clarify a few things, molecular weight of oxygen (32) is more than that of nitrogen (28) but molecular size of nitrogen is more which results in slower leaks.

Source: http://www.getnitrogen.org/pdf/graham.pdf

Originally Posted by Spitfire

Any technical reasoning as to how nitrogen can reduce tyre noise?

This is my hypothesis. Air has moisture which conducts sound faster. At certain speeds this can lead to resonance from the tyre vibrations. Nitrogen being dry conducts sound slower and hence avoids this resonance from occuring. If my hypothesis is correct nitrogen filled tyres should have more tyre noise at less speeds but less noise at high speeds.

Sorry for adding more fuel to the debate!

[anupmathur]

Originally Posted by 71Convertible

2. The purity of N2 created by the N2 generators commercially used is not 100%, but is closer to 95%.

This is a point that is yet not quite understood. What kind of Nitrogen producing equipment are these various bunks using?
Further, no compressor will yield 'dry' gas! Filters and dryers will necessarily need to be used to obtain DRY gas! And that is exactly the same for compressed air.

Originally Posted by watashi75

Nitrogen being dry conducts sound slower and hence avoids this resonance from occuring.

Inherently, Nitrogen is no dryer than compressed air!
Filter/dryers have to be deployed to make the nitrogen dry, same as with compressed air!
Also, to get the final 99% plus purity is something that is entirely 'process' dependent!

All in all, it is safe to say that there is tremendous scope for 'fooling' the customer and making BIG bucks in this game!

[kaushik_s]

Originally Posted by anupmathur

All in all, it is safe to say that there is tremendous scope for 'fooling' the customer and making BIG bucks in this game!

Exactly Anupji, that's also my worry about. Already the car enthusiasts been fooled a lot by many such kind of things. And if I list out similar things then it'll be a war of words .

[Spitfire]

Originally Posted by watashi75

This is my hypothesis.

I have seen this hypothesis proved by a lot of... guess who? - Nitrogen Filling equipment manufacturers

Do a google you will come with a few.

Air has moisture which conducts sound faster. At certain speeds this can lead to resonance from the tyre vibrations. Nitrogen being dry conducts sound slower and hence avoids this resonance from occuring. If my hypothesis is correct nitrogen filled tyres should have more tyre noise at less speeds but less noise at high speeds.

Now lets try and prove this hypothesis.

As per the above hypothesis noise within the tyre(tube) due to resonance is reduced by N2 instead of Air.

A brief on how sound is produced:

When an object vibrates in a medium it creates vibrations through air(like waves) that are picked up by our ears and our mind decodes them as sound.

When a tyre vibrates and the corresponding vibrations inside the tube will create a sound inside the tube.

Again as per physics sound will be propogated through a continuous medium. Now inside a tube which is sealed the sound cannot propogate beyond the walls of the tyre tube. So the sound propogated inside a tube by either N2 or Air will not be heard outside.

The sound waves (vibrating molecules pushing each other) will bounce off the walls of the tube.

So we prove that the hypothesis is wrong.

The other part of the hypothesis, slow speed and high speed... well thats totally baseless.

Another example soundtight rooms - Try and find out why the sound never comes out. Remember the key word - Continuous Medium.

Instead of trying to prove the above, i could have just mentioned that the sound that you hear from a tyre is not from within the tyre but due to the fact that the tyre is in contact with the road. Rubber compounds which make up the tyre determine the noise level.

Ever wondered why a bullock carts wheel(the old wooden ones with a metal strip) make more noise even though they have no air in them

On another note: Einstein sir, we are here for you, please do not get uncomfortable in that grave.

Sorry for adding more fuel to the debate!

Oh its loads of fun and a lot of learning and unlearning. Keep going.

[enzo10]

Originally Posted by kaushik_s

Exactly Anupji, that's also my worry about. Already the car enthusiasts been fooled a lot by many such kind of things. And if I list out similar things then it'll be a war of words .

totally agree, the list will look some what like this:

1) K&N or green air filters for Maruti 800 and alto
2) Koni suspension and alloy wheels for sub-1.6ltr cars

members please feel free to add to this list

[71Convertible]

Originally Posted by watashi75

Just to clarify a few things, molecular weight of oxygen (32) is more than that of nitrogen (28) but molecular size of nitrogen is more which results in slower leaks.

Source: http://www.getnitrogen.org/pdf/graham.pdf

with the molecular size argument -- There is more likelihood of losing pressure due to faulty valves or punctures than thru the tire wall. The openings in those cases are bigger than molecule size and in those cases N2 filled tires will actually lose pressure faster.

[watashi75]

@Spitfire, one more hypothesis.

Nitrogen filled tyres will have less temperature fluctuations than regular air. Hence brownian motion, which is essentially noise, will be less and hence lead to less tyre noise. I can hardly understand what I am saying but if this hypothesis is correct, dry compressed air will also produce less tyre noise.

Now beat that!

OT: Does dry NO2 lead to dry humor?

[kaushik_s]

Let me add that K&N FUEL filter thingy also.
And Iridium plugs for our normal daily drive cars.

So now the list is,
1) K&N or green air filters for Maruti 800 and alto
2) Koni suspension and alloy wheels for sub-1.6ltr cars
3) K&N Fuel Filter
4) Iridium Plugs for our normal daily drive cars
5) Nitrogen in the Tires he he
What else??

BTW, spitfire is on full fire

Originally Posted by enzo10

totally agree, the list will look some what like this:

1) K&N or green air filters for Maruti 800 and alto
2) Koni suspension and alloy wheels for sub-1.6ltr cars

members please feel free to add to this list

[mobike008]

I followed a simple policy. Filled Nitrogen in my head..uhh..sorry in my tyres, everything seems so good now that I forgot all logic and simply enjoying the pleasure that it provides coupled with the fact that i now check my air once in 2-3 months ( that itself proved as a joy point) and just sit back and enjoy you N2 gurus discussing its logics,physics and chemistry.Sounds good?

[Spitfire]

Originally Posted by mobike008

Filled Nitrogen in my head

Try Helium next time. Cheaper then Nitrogen too. Just dont take your head close to a burning candle.