Nitrogen in tires.

[Ol' Jeffers]

Just wondered how many of you guys in the 'States have your tires inflated with Nitrogen.
My tyre shop owner over here in the UK uses nitrogen in all the tyres which he fits and doesn't charge extra money for it.
He says that the equipment to produce the gas is cheaper to run and maintain than using ordinary air.
Nitrogen inflation has quite a lot going for it especially on bikes and the pressure in the tire doesn't seem to deplete
as rapidly as air.

[Hottech]

Malarkey, the air you normally put in your tires contain 78% nitrogen to begin with. There is no added benefit to adding any additional nitrogen.

[hank]

Malarkey, the air you normally put in your tires contain 78% nitrogen to begin with. There is no added benefit to adding any additional nitrogen.

You beat me to it. I was gonna say snake oil.

[omg1010]

Why not inject helium into your tires. Might make your bike lighter!

Brgds
Oliver

[kirby]

0

[Ol' Jeffers]

Nitrogen also has a lower co-efficient of expansion and is used on most race bikes and cars.
Different strokes I suppose....but if it's free then I shall continue to take advantage
of the benefits it offers!

[touchton]

The big problem I have with using nitorgen is paying extra for it. Sure, there are some advantages, but they are very minimal. Since it's free for you, it's worth every penny. But, if someone is selling it for a couple of dollars per tire, they are selling snake oil......

Thad

[kirby]

2

[gregor]

No not snake oil, its called choice. Tire pressure will change very little cold or hot or with large altitude changes. No water to cause corrosion. Its just plain better in many ways than outside air. The cost is another matter. I change my own tires and the small amout of benefit to nitrogen is not worth the time to take the tires to the local airport just to fill them..its a convenience thing. Snake oil its not.

So you start with a tyre(tire) full of natural soggy atmospheric air, at one bar. Do do you get rid of that before inserting the dry nitrogen?

[Jed]

There's a lot of bad science thrown around by those that have a financial interest in pushing nitrogen for tire inflation.

1) Nitrogen does not have a "lower co-efficient of expansion". Nor does that term have any meaning. Nitrogen responds to thermal changes just as any other gas does by expanding at a rate proportional to the change in total energy.

1a) The advantage attributed to nitrogen regarding thermal stability is an effect of the reduced amount of water found in compressed nitrogen versus compressed air. It's water changing from a liquid to a vapor (or the reverse) that causes the non-standard variations in tire pressures for a tire that picks up some water due to inflation with compressed air. If the compressed air is well dried, then the response to temp changes would be the same for compressed air and nitrogen.

2) "Nitrogen molecules are larger and hence "leak out" more slowly than the oxygen in compressed air". This is not entirely untrue. Nitrogen molecules are marginally larger than oxygen molecules and so are slightly less inclined to leak out through the pores of the tire. But the difference in size and hence this effect is minimal.

2a) What the nitrogen sellers won't tell you is that the differences in concentrations and pressure between the gas inside the tire and outside the tire with cause nitrogen to leak-out of the tire more quickly and oxygen to leak-in. At any rate the effect that a larger size of molecule may have in reducing leakage is minimal.

3) Nitrogen is not inert, but it is less reactive than oxygen, by a good margin. Tires inflated with nitrogen with therefore have less oxygen available to corrode various steel (rims or belts) that it may come in contact with. Aluminum rims are a different story in that aluminum oxide (aluminum's version of rust) is harder that pure aluminum and is considered a protective layer for anything made of aluminum.

Nitrogen does not support combustion (which by definition is a reaction with oxygen), but when things catch fire it's not the oxygen in the tires that leads to combustion. Tires do not burn from the inside out.

All that being said, it is marginally advantageous to inflate your tires with a dry gas like nitrogen if the cost is not an issue. If I had a free source of compressed (dry) nitrogen, I would use that to inflate my tires rather than compressed air. For use on a motorcycle, keeping tires properly inflated with any gas (air or nitrogen) is better than riding around on poorly inflated tires. Whether it's snake oil or not depends on how finely you want to split hairs.

cheers,

[kirby]

3

[R100CS]

If the O2 leaks out how many refills until there is only N in the tyre?

Lets do some calculations:
Air = 80% Nitrogen.
Fill a tyre with air => 80% N
It deflates, keeping the 80% N in.
Repressurise and fill it op with Air.
80% of 20% is 16% so 16% N is added to the 80% is 96% N.
After another refill, 80% of 4% is 3% you'll get 99% N.

So after a couple of refills the tyre almost only contains Nitrogen.
To use Nitrogen in special applications like aircraft, I understand, but using it for motorbikes...
I think it won't harm, so if you like it go ahead, if it doesn't cost extra OK, but paying for Nitrogen is not for me.

[acejones]

P. T. Barnum was right !

[towerworker]

Jeffers---you just go on and keep puttin' nitrogen in your R's tires and I'll keep puttin' antifreeze in my R's radiators. What do these guys know anyway.

[Ol' Jeffers]

@ Towerworker! I'll do just that. I don't have the choice! My tire shop owner doesn't charge
for it but it goes in all the tyres he fits because he says that for him it's an cheaper option
to compressed air! I get the tyres at a good price and he's been a biker for 30 years so at least I'm
sure that'll it do no harm. I have an added step to changing the anti-freeze! I always use HOT water
in the mix as then the anti-freeze doesn't wear out so quick!

[acejones]

I fail to understand how your shop guy can produce nitrogen cheaper than compressed air.

[omg1010]

Probably that kind of voodoo guy who turns lead into gold ...

Brgds
Oliver

[Ol' Jeffers]

I don't believe that I came here to be insulted, Oliver. The man is a friend who I have known for over 20 years.
I'm sorry, but if it becomes necessary for you to forgo courtesy for a cheap laugh then I'm clearly in the wrong place.

[acejones]

Jeffers,
I don't believe Oliver meant that as a direct insult. Your original question raised an interesting process point. Next time you go to a parts store, hardware store, or mechanics shop, look around and see how many air compressors you find. then look around and see how many nitrogen compressors you find. Nitrogen is a component of air. In order to get pure nitrogen one would have to run some type of separation process. That is going to increase process complexity and therefore raise cost from the raw material (air). That's why it seems incredulous that your friend is producing nitrogen for free.

[kirby]

4