OT; Nitrogen filled tires

Nitrogen Tire Inflation vs. Temperature Change
There is no significant difference in expansion and contraction
characteristics of nitrogen compared to air when moisture is absent.
Expansion or contraction of either gas, in relation to temperature change,
occurs to a similar extent over the commonly encountered pressure and
temperature ranges relevant to the discussion of tire inflation. There is
no practical difference as long as the gases are dry in a fixed volume
container such as a tire.

On the other hand, water is usually present in the case of conventional
compressed air where dewpoints can be as high as 70F, compared with -50F for
nitrogen. At lower temperatures, water (as a liquid) occupies very little
volume. However, as temperature increases liquid water vaporizes to become
a gas and its volume expands. This causes total tire pressure to be higher
than it would be in the case of a dry gas, such as nitrogen. Thus the
presence of water in a tire contributes to wild pressure variations as
temperatures change.

The pressure in nitrogen filled tires will change when the temperature
changes, just as it does with compressed air filled tires because nitrogen
responds to changes in ambient temperature in a similar manner. For
example, when your vehicle is parked, it will lose 1.9% of its pressure for
every 10F change in temperature. These calculations are based on the ideal
gas law. If a tire is filled to 32 psig at a temperature of 75F, and the
outdoor temperature is 35F, the tire pressure will drop to 29 psig. These
fluctuations will occur as the temperature rises and falls, regardless of
the inflation gas. Fortunately, tire manufacturers are readily aware of
these parameters and set their cold inflation pressures accordingly.

So, the bottom line is that you will still see pressure changes with
nitrogen. But they should be more consistent and run cooler than if they
were filled with compressed air.



The properties of nitrogen tire inflation are well known:


1.. Nitrogen filled tires retain their pressure longer than those filled
with compressed air. A typical tire filled with compressed air will lose up
to 2 psig/month, it takes 4-6x as long to lose that 2 psig with a nitrogen
filled tire.
2.. Nitrogen is very dry, with a dewpoint of about -50F. This eliminates
any moisture (liquid or vapor) within the tire casing.
3.. Nitrogen is non-reactive and practically halts breakdown of the
rubber.
These properties yield a variety of benefits for the average driver

1.. Fuel Efficiency Improvements: By maintaining proper tire pressure
longer with nitrogen inflation, gas mileage will be maximized.
2.. Tire Life Improvements: Since the permeation of oxygen through the
sidewall is minimized with nitrogen tire inflation, rubber retains its
strength longer. This, coupled with the better pressure retention, provides
longer tire life.
3.. Safety: Underinflation was a factor in 32,000 automobile fatalities
in 1999. This is minimized with nitrogen.
4.. Environment: Underinflated tires waste 2.8B gallons of gasoline/year
and emit additional greenhouse gases. Maintaining your proper tire pressure
longer helps to minimize both wasted gasoline and greenhouse gases.
Here is a piece of literature from Bridgestone that explains these benefits
well.

http://www.getnitrogen.org/pdf/Bridgestone.pdf

 

eh? but fill air is not heated, and certainly not to 75'F when it's
35'F ambient. that's a bogus argument.

bogus reasoning.

that's because of partial pressures, not because nitrogen diffuses
through rubber slower.

no, it's not "dry" any more than air without water vapor in it.

ok, not that oxidation is a significant problem though...

if they are.

tires wear out /long/ before they oxidize.

not any more than with air and properly checked tires it doesn't.

bogus - that assumes underinflation which can occur just as easily with
nitrogen if neglected.

 

OK Jimmy. I guess I am not a literary expert so I shall comment for each of
your comments to try to clarify the meaning. Some of the statements might
be applicable to some people more than others. Each person has to determine
if the value is there for them before changing to Nitrogen. I have used
Nitrogen in my aircraft tires and have found if the tires are on a hot
airport ramp in the summer or in the middle of a Minnesota winter the tire
pressure does not change much. A small tank of Nitrogen with a regulator on
it does not cost very much and will fill all the tires the average person
has for many years. Even the tire on my wheelbarrow has Nitrogen as I just
don't check it's pressure every time I use it.

Enough said Jim. Lighten up a little.

Paul

eh? but fill air is not heated, and certainly not to 75'F when it's 35'F
ambient. that's a bogus argument.[/QUOTE]
**I think it would be warm in a service shop in the winter. Also
compressing air creates heat so the air being used to inflate a tire could
easly be 75'F when the outside temp would be not only 35F but maybe -35F.**

**I wonder what your source is in making that statement?**

**I wonder why many tire company's say nitrogen filled tires hold pressure
longer**

**We have used Nitrogen for many years to fill communications cables because
it is dry. I suppose if you filled your tires in the middle of the Saraha
desert the air would be fairly dry but in Minnesota it would be about 50%
wet most of the time.**

**Gee, I'm glad you agree with one statement. LOL**

**A lot of people do not check their tire pressure very often.**

**Maybe your's do but there are many vehicles that have older tires on
them.**

**Again many people do not check tire pressure on a regular basis.**

**Somewhat true but if they don't loose pressure as fast then they would not
be underinflated as often.**

 

for a/c, you want to make sure you have all the bases covered. for cars
though, it's simply pointless, although a great additional source of
revenue for tire shops.

that's a joke, right? wtf would anyone, who understood the facts at any
rate, spend money doing that when they can use air for free at the gas
station???????????????

ok, that's just ridiculous.

and you keep inflating your aerospace grade wheelbarrow with nitrogen
paul!!! got to make sure those tire pressures are safe after re-entry!

**I think it would be warm in a service shop in the winter. Also
compressing air creates heat so the air being used to inflate a tire could
easly be 75'F[/QUOTE]

in the compressor, but not in the tank or the feed lines. and even if
it was "hot" in the tank and feed lines, it still loses temperature
immediately it gets into the tire - it's an adiabatic process.

bogus. see above.

it's true, they do because of partial pressures - look it up.

but that means the tire fills with other atmospheric gases while it's
losing nitrogen.

that's a water vapor/freezing thing. for a car, the only time it's
going to be an issue is if the valve freezes. and by far the most
likely cause there is not using a dust cap - hardly an issue solved by
nitrogen.

do /you/ think oxidation is a significant problem???

so? which do you think makes the most difference? not checking
nitrogen pressures or not checking air pressures? and which are more
likely to be checked - the tires you can inflate at the gas station or
the ones you have to go to the tire shop for and wait in line???

do /not/ confuse oxidation with u.v. deterioration. the former is
almost never seen, the latter is endemic.

particularly so if they have to go to a tire shop and wait in line!!!

but that is negated by the inconvenience of unavailability.

 

"Each " is singular, therefore each person must determine if the value
is there for him, not for them.

 

My tires have, what--78.084% nitrogen in them.

Problem solved.

 

What if it is a her?

 

Great! Your 78% there....

LOL

 

78% of the way to not wasting your money on making your aerospace grade
wheelbarrow fit for re-entry to earth's atmosphere after orbiting planet
ain't-gotta-clue.

and it's "you're" as in "you are", not "your".

yes indeed.

 

If you are referring to a specific individual AND know that it's a
woman, you use "her". Otherwise, you use "him" as a general use
singular pronoun.

(I wonder what the politically correct crowd is going to do when they
finally attack Spanish and French and all those masculine and feminine
nouns...)

 

Is your glass half full or half empty???

 

Kind of comical when you consider he doesn't know where or how to use a
shift key...

JT

 

does that somehow switch off top posting??? if so, maybe you should
look into using one.

meanwhile, unlike you two, i know what diffusion is and know what
partial pressures are. maybe if you two redeployed the time you spend
wasting electrons on usenet posting irrelevant garbage, you'd learn
something useful.

 

Hello there Mr. Jim Beam;

I think from now on instead of using Google and the other search engines,
the encyclopedia, television, the Library and others for information I now
can just ask you because you know everything.

Paul