Nitrogen in Tires

Gimmick waste of time nonsense.

 

Tires are a gel made from rubber and carbon black oil. The rubber is EPDM, SBR, or natural rubber and is usually a blend of all 3...plus special additives.

That gel is permeable to oxygen and nitrogen. So with no other barriers, tires would lose pressure in a matter of weeks.

That's why modern tires have a lining on the inside made from halobutyl rubber. Butyl rubber is basically impermeable to oxygen and nitrogen. It has lots of uses where sealing air is important (like the stopper on those vacutainers they use to draw blood samples).

But pure butyl rubber won't bond to tire rubber. So, they add a chlorine or bromine to each monomer isobutylene and then it's still impermeable and will bond to the inside of the tire. This barrier (halobutyl rubber) all but stops air diffusion.

If you're losing 1 psi per month, you have a leak. It's not diffusion.

BTW, if you have white-walls or raised white letters, there's a layer of halobutyl under the white rubber. It stops the carbon black oil from diffusing and yellowing the white part.

Nitrogen is a cheap source of dry gas. They have to dry the air when they make nitrogen because the separation process operates at over 100 degrees below zero. Water would freeze and plug the equipment.

When you compress air, the water content in and out of the compressor is the same, beacuse the compressor heats the air. When it cools in the tank (at pressure) water may condense out if there was enough to start with. So, the air in a compressor tank, at pressure, but also at ambient temperature can be drier than the source air. In Houston you have to drain the tank periodically. In Phoenix, you probably don't.

When the compressed air goes into a tire, whatever water was in the tank air also goes into the tire, but the pressure is lower. This drop in pressure lowers the relative humidity of the tire air. The problem is that water holding capacity of air varies very strongly with temperature. So, even if the water is a vapor when warm it still might condense on a real cold day or at altitude. The water might lead to an imbalance in the tire, so if it rotates real fast (airplanes, race cars) this is a problem. At 65 MPH, a gram or 2 of water won't be noticed.

Nitrogen and oxygen (and the mix, air) are all ideal gasses at low pressures (less than ~500 PSI). They expand at the same rate.

For two different conditions (1 and 2), P1T1 = P2T2 (where P and T are absolute). What the molecules are doesn't even appear in the equation and doesn't make any difference.

 

Re: What about the overal environmental impact?

Chiropractics - disagree, it does help someone with spine misallignment conditions, but useless for generally healthy people.

homeopathy - agree, just snake oils.

acupuncture - absolutely disagree. Please research a little bit on the subject, you'd be surprised what this 5000 year-old Chinese medicinal practise can do, and that even the governing bodies of medicine have approved it worldwide. There are fully qualified MD's in Canada who also practise acupuncture. Please do not disregard something lightly just because it originated from a foreign country long time ago.

 

When I was buying the Pontiac G5 for my son last year, one of the dealers wanted to charge me $200 for nitrogen in the tires. I said thanks but no thanks, but the salesman said it's not optional, because ALL of their cars have already been pumped up with nitrogen. He was not lying just didn't say there's 20 odd % of the gas in the tires are oxygen.

Obviously I didn't buy from him. It's something the dealerships allow the sales people to do just to fatten their pockets.

 

Re: What about the overal environmental impact?

One of our local MDs practices acupuncture.

Tom

 

Another worthless message.

I tried to post on another thread a message with helpful links, but the Prius Chat system informed me that as a new user I must post five messages before it will permit me to post one with links. I've now posted four relevant messages in some other threads, but I need to post one more.

Having now skimmed through the nine pages of this thread, it appears quite appropriate to post another irrelevant, time-wasting message to this thread. Certainly, no PC user who values his or her time will wade through the nine pages of this thread to get to this.

 

We run Helium in our lab, and have found swapping the air increases mileage my 3.14 MPG! That from Nitrogen - which is kinda silly to use - since nitrogen is what is really in all our tires anyways - due to our atmosphere.

We found the Helium slowly gets diluted (nature), but it really works great on mileage, and driving 'feel'.

 

Lemme guess - when you corner hard, or panic stop, the screech is much higher-pitched, and kind of warbly-sounding?

 

LOL! I was going to joke about helium, too.
Wait, you are not serious, are you?

 

increase mileage my nice person...

 

Re: What about the overal environmental impact?

The very large HMO I use has acupuncture departments at some of it's locations.

 

When I tried it the tire popped off the rim and twisted itself into the shape of a little dog.

 

I tried helium and it made no diff in the tires. But in the cabin it makes enough diff because it's a much greater volume. I put better sealant on all the doors and when making a trip I now close the doors then an exchanger removes all oxygen and replaces with helium from a tank under the dash. So that I can breath I use a SCUBA tank. Gives me about 12 extra MPG, particularly on hills.

 

We tried helium in our lab and when she barked she sounded like a chihuahua

 

Why replace just the oxygen? If you replace the entire interior atmosphere, including nitrogen, you can get 5x more buoyancy and mpg increase, and delete the expensive exchanger.

 

All that talk about helium. People, hydrogen or even vacuum is lighter than helium! BTW, myth-busters did a study on helium in footballs. Guess what, they flied a couple of inches shorter.

 

Good idea! Fill those tires with vacuum; all you need is a vacuum pump.

Tom

 

You, sir, have caused me to laugh out loud. But I know I can get this stuff in the store. It's sold in vacuum bottles.

 

Does the helium make the car lighter?

 

Re: What about the overal environmental impact?

Well a year later, 40 lbs per tire, all still there, winter tires last checked at 40lbs per tire atmospheric air are at 22lbs and dropping. Works for me.