nitrogen-filled tires

Waste of time, waste of effort. Little if any benefit for street cars. We've been through it before, and beaten it to death in these very forums.

Your ambient air is already mostly Nitrogen, so knock yourself out and use a regular air pump to get all the nitrogen you'll need. No matter what you fill the tires with, you'll need to chech them regularly anyway.

 

I agree with Darell.

Oh, and nitrogen expands just like any other gas as it heats up. Laws of physics and all that...

 

An old trick to keep you coming back to the store, so that you can buy stuff you don't need.

 

Try argon instead. It costs more than nitrogen so it must be better.

 

<div class='quotetop'>QUOTE(8AA @ Jan 1 2007, 10:51 AM) [snapback]369227[/snapback]</div>

I think use hydrogen so the wheels will be lighter, but make sure to tie the molecules together or they will slip through the rubber.

Tom

 

<div class='quotetop'>QUOTE(qbee42 @ Jan 1 2007, 10:06 AM) [snapback]369231[/snapback]</div>

What if you combined it with oxygen, at, say, a 2-to-1 ratio?

 

<div class='quotetop'>QUOTE(Stev0 @ Jan 1 2007, 07:41 AM) [snapback]369234[/snapback]</div>

Oh yes... Dihydrogen Monoxide

http://www.dhmo.org/facts.html

 

<div class='quotetop'>QUOTE(Stev0 @ Jan 1 2007, 10:41 AM) [snapback]369234[/snapback]</div>

Yes, yes! This is a great idea. Then it would be nearly immune to pressure changes, at least above freezing. :blink:

Tom

 

As Darell and others have noted, plain old regular air is already 78% nitrogen, so you're not gaining much by going with "pure" nitrogen. Also, in accordance with Boyle's law, the change in pressure in your tires as influenced by temperature is identical regardless of the gas contained inside.

This myth has some basis in truth, although its not the nitrogen itself that earns the credit. Seems that aircraft tires were always filled with nitrogen and that translated to racing car wheels and other high performance tires. Everyone assumed that nitrogen was the only way to go...any anyone who wanted the best performance naturally wanted nitrogen.

So what is the real advantage? Compressed nitrogen is completely DRY. As in no water. Anyone who watches TV news knows that plain old air contains water vapor (its called humidity). Put 100 litres of air into a 10 litre compressor and you also put the WATER in that 100 litres of air into that compressor tank. Commercial gasses are dried, but if you just use an air compressor like most tire shops, you're getting air with humidity.

Water in your tires can change the pressure slightly if it goes in as water and then turns to water vapor (or vis versa). But for airplane tires, it means water can condense inside the wheel and then freeze at high altitude. If it gets in the valve stem area, it could cause a leak...very remote possibility...but it could happen.

So its the water you're avoiding when you go with pure nitrogen. You could use any compressed commercial gas - they're all dry - but nitrogen is the cheapest. If you want some real fun, ask for Argon or Xenon next time.

 

<div class='quotetop'>QUOTE(nicos @ Jan 1 2007, 08:43 AM) [snapback]369245[/snapback]</div>

And for my next trick, I will actually drink an entire glass beaker filled with dihydrogen monoxide. In this amazing feat, you will see me swallow one of the most potent solvents known to scientists. I use no mirrors or tricks. No slight of hand. Yes, kids, you may indeed try this at home.

 

<div class='quotetop'>QUOTE(darelldd @ Jan 1 2007, 12:55 AM) [snapback]369158[/snapback]</div>

Only to those who don't want to tr something out, before they knock it, is it a waste of time. And, hmm. As one who is trying this out, of today, no loss in pressure after a month...not one bit.

So, I will check again next month...oh, and my fill ups are free, if I need them. Heck, at most gas stations, you got to pay something...

Knocking something because you don't like it is a waste of time.

 

<div class='quotetop'>QUOTE(Bryanmsi @ Jan 1 2007, 04:30 PM) [snapback]369313[/snapback]</div>

absolutely correct.

Especially on any car with an inside tire TPMS (Tire Pressure Monitoring System) you want as little water in your air as possible.

apart from the no-water benefit, you loose very little air pressure as compared to "regular" air. the heat expansion is MUCH less of a benefit on a street car as it is vs a race car so I wouldn't even consider that a reason to use nitrogen vs. "normal" air.

 

Most good shops have the appropriate water trap on their compressor anyway. They don't want water in the air-powered tools or the lift system.

TJandGENESIS, I wouldn't expect your tires to lose pressure quickly anyway, no matter what they're filled with. Check next month. I check mine every month and they usually get a couple of PSI bump. This is normal.

Now, as for free fill-ups, there is a big issue:

When you drive to the shop for a fill, you've warmed your tires; they now read a few PSI higher than normal. You should check pressure with tires at room temp. So, do you go to the trouble of testing, writing four pressures, driving to the shop, then compensating when you're at the shop? You'd have to say "I want this tire at 38, so fill it to 41 because it's warm."

(Actually, the engineer in me would bleed off a bit from the harder tires so all four are equally low. Then it's just a matter of adding a few PSI for the temperature as you fill them.)

 

I want to being up an old topic since more tire shops are using Nitrogen.

Air is 78% Nitrogen, but the other 22% can hold a lot of moisture.
Air Compressors compress the air and water vapor to 100% Humidity with the water collecting in the bottom of the tank. Most Air Compressor tanks have water traps and air dryers, but many are NOT maintained and will spit water.

I've been putting Nitrogen in my tires for over 10 years at Dunn Tire in Rochester, NY. I get my oil change and tire rotation at another garage for under $20, but I tell them not to check the pressure. I then go to Dunn to get Nitrogen. You don't need an appointment, just drive up and have them add what you need. I add more than I need, 43 psi in all tires. In the morning with cold tires I check, adjust down to 41 psi front and 39 psi rear, re-set the Tire Sensor System and then drop the pressure another 2 psi to remove the Sensor System error, leaving the front at 39 psi and rear at 37 psi, which is 4 psi higher than the door sticker.

I agree with the other Nitrogen advantages of no moisture, less internal tire rot or rim rust and slower loss of volume through the tire walls, but I'm really interested in the pressure vs temp properties. How much will the tire pressure increase as the tire temperature increases?

Has anyone ever used continuous readout Tire Pressure Sensors and can you document the Pressure vs Temp for Air or Nitrogen filled tires? Let us know.

 

The dryness is an advantage, but it's not unique to nitrogen. Dry air works equally well. Likewise you need to ask if your tire shop uses a water based lubricant when mounting tires. If they slop a bunch of water on the rims while mounting, it doesn't make much difference if the gas is dry.

The temperature-pressure curve and diffusion rates for nitrogen are essentially identical to those for air. Don't expect any gains in those areas. Rot and rust should theoretically be better, but the oxygen in a sealed tire will quickly be captured, so that area isn't much of an improvement either.

Nitrogen fill for car tires is essentially snake oil.

Tom

 

hmmm... I have an Argon tank at work... But then Argon is a LOT heavier than air (or nitrogen - 42% heavier than nitrogen). I had argon filled windows put in my house and the panels are noticably heavier than the air filled.

 

I believe "Boyles Law" explains it all.
Standard atmosphere is approx 70% Nitrogen anyway!
5% rare gasses, the rest O2....

42 front 40 rear regular air works just fine for me....

 

Just to be anal about it.

 

No need to go to all that trouble. Nitrogen and Oxygen both follow the Ideal Gas Laws close enough that you can't tell the difference with a tire gauge.