When they inflate tires.....................

Posted By: Pyper70

When they inflate tires..................... - 06/15/09 09:33 PM

do they use some special air in the compressor or a chemical for sealing?

My old man was telling me this as I noticed all my tires on the 69 went from 32 down to 27.5....he laughs as his GMC van has held 34psi on all 4 tires for 6 years

Posted By: stumpy

Re: When they inflate tires..................... - 06/15/09 09:43 PM

Nothing but compressed air. Loss of air has to do with the outdside temp and porosity of the tire rubber as well as the seal to the rim.

Posted By: Scott Carl

Re: When they inflate tires..................... - 06/15/09 09:43 PM

Yeah its cal t'ar ayre. You just don't have to change yer air as often. Yer dad, OTH is waaaay over due

Seriously, tires should seal on the rim with nothing but the lube (soapy water) they use to mount them. If they leak, there's either a bad valve stem, bent or gouged rim, or a hole in the tire (or dry cracked) or a combination of all of the above.

Posted By: scratchnfotraction

Re: When they inflate tires..................... - 06/15/09 09:47 PM

an inner tube

nitrogine maybe

compressed air

gas co2 out of the fix a flat with sealent from a can

Posted By: Posest

Re: When they inflate tires..................... - 06/15/09 09:57 PM

A lot of the tire shops are going to a nitrogen fill rather than compressed air. The theory is that nitrogen does not expand and contract with temp changes like compressed air does. For example blow up a balloon, tie it and put it in the freezer. Take it out an hour later and see that it has shrunk. Leave it out in the sun and it will expand. Supposedly nitrogen will not shrink or expand. I am not a chemist, just relaying what I have been told. Green valve stem caps indicate nitrogen filled tires. It is also compatible with normal compressed air.

Posted By: MoparforLife

Re: When they inflate tires..................... - 06/15/09 10:30 PM

Quote:

do they use some special air in the compressor or a chemical for sealing?

My old man was telling me this as

Get some respect.

Posted By: 340SHORTY

Re: When they inflate tires..................... - 06/15/09 10:37 PM

Nitrogen molecules are larger than air molecules,,, hench less leakage

Posted By: DPelletier

Re: When they inflate tires..................... - 06/15/09 10:54 PM

The use of nitrogen in passenger car tires is nothing but a sleazy cash grab by the retailers.

Did you use a different gauge both times you checked the pressures? Were the tires at the same temperatures both times?

Dave

Posted By: Publicbottle

Re: When they inflate tires..................... - 06/16/09 12:02 AM

Its true that nitrogen has more resistance to temp changes, there is just not as much compared to regular compressed air which happens to be full of moisture, which is why your air pressure in your car tires would flucuate depending on outside air temp or seasons. In aviation we use dry nitrogen, but I still see effect of temps on tire pressures...just not as dramatic. For example an aircraft tire will be filled to 150psi at room temp. after a couple landings the brakes while heat up that area and the tire pressure will increase to around 160psi due to the increased temp of the friction braking.

Posted By: RodStRace

Re: When they inflate tires..................... - 06/16/09 12:19 AM

and that there nightrogen will clean yer engeen too, I saar it on TV!

The fact that nitrogen is a large part of air means the returns are less to do with moisture and stability ( the other gasses change more easily to temperature) than to the fact some people have to have what the racers have and there are others willing to sell it to them and advertise it to the masses to cover the costs and generate a profit.
Every time I see another grimy set of wheels with those caps, I recognise that there is one more person that doesn't check their tire pressures, but is willing to spend a bit more to keep it stable...

Posted By: deansrr

Re: When they inflate tires..................... - 06/16/09 02:24 AM

Quote:

The use of nitrogen in passenger car tires is nothing but a sleazy cash grab by the retailers.

Did you use a different gauge both times you checked the pressures? Were the tires at the same temperatures both times?

Dave

I must be one of those sleazy cash grab tire retailers because I sell it and install FREE on all tires I sell! Been using it for over 4 or 5 years now, have had great luck. Nitrogen will keep your tires running cooler (longer life), keeps moisture away, less corrisoin between rim and tire bead, less rim leaks (if you have had a Chrysler with chrome rims you know what I mean) and yes air pressure doesn't change as much, It won't stop the air from leaking' but with the larger moducles it slow its down and without the moisture it doesn't change as much. Again I'm only a sleazy cash grab tire dealer, so what do I know after 35+ years in the business

Posted By: deansrr

Re: When they inflate tires..................... - 06/16/09 02:32 AM

to anwser your ?, different tire companies have different bead sizes, so if you have a tire that has a loose fitting bead on a rim that is also a loose fitting rim you will lose more psi as compared to a tight fitting rim and tire. Chrome rims also are know to leak down faster. And no there is nothing that we use except mounting lube. I hope this helps

Posted By: Anonymous

Re: When they inflate tires..................... - 06/16/09 02:50 AM

Quote:

Nitrogen will keep your tires running cooler (longer life),

Can you provide anything to back that up?

Quote:

keeps moisture away, less corrisoin between rim and tire bead

It doesn't keep moisture AWAY, it's just that hopefully there's less moisture in the N2 to begin with. Since there's much less O2, rust/corrosion is slowed way down.

Quote:

air pressure doesn't change as much,

I'm pretty sure the reason for this is the fact that there's not much moisture in N2 Atmosphere is largely N2, anyhow, and I can't imagine that the difference in delta T change for N2 and O2 is very much.

You PROBABLY could accompomplish the same thing with CO2, and except for inhibiting rust/ corrosion, you could probably use dried air the point being that there's nothing really magic about N2

Posted By: RapidRobert

Re: When they inflate tires..................... - 06/16/09 02:57 AM

I'd air em up in your shop rather than at a station as I cant believe the amt of water I see spewing out of the air chucks at most of those places

Posted By: deansrr

Re: When they inflate tires..................... - 06/16/09 03:16 AM

Quote:

Quote:

Nitrogen will keep your tires running cooler (longer life),

Can you provide anything to back that up?

Quote:

keeps moisture away, less corrisoin between rim and tire bead

It doesn't keep moisture AWAY, it's just that hopefully there's less moisture in the N2 to begin with. Since there's much less O2, rust/corrosion is slowed way down.

Quote:

air pressure doesn't change as much,

I'm pretty sure the reason for this is the fact that there's not much moisture in N2 Atmosphere is largely N2, anyhow, and I can't imagine that the difference in delta T change for N2 and O2 is very much.

You PROBABLY could accompomplish the same thing with CO2, and except for inhibiting rust/ corrosion, you could probably use dried air the point being that there's nothing really magic about N2

nitrogen is pretty much dry air, that is what I meant by keeping the moisture out, without the humity of moist air your tirs will run cooler thus extending the life of your tires.

Posted By: Posest

Re: When they inflate tires..................... - 06/16/09 04:12 AM

I have those green caps on my grimy wheels. Sad thing is that I do check my tire pressure. Stays around 40 psi on my Toyota beater. I have more rust than solid panels. I am a firm believer in good tires and keeping the right tire pressure. I have yet to pay for nitrogen in any tire inflated with it. Seems that even in college they are teaching the positive effects of using nitrogen in tires.

Posted By: john55

Re: When they inflate tires..................... - 06/16/09 06:19 AM

Quote:

Nothing but compressed air. Loss of air has to do with the outdside temp and porosity of the tire rubber as well as the seal to the rim.

the air we breathe is almost 80% nitrogen

Posted By: DPelletier

Re: When they inflate tires..................... - 06/16/09 04:54 PM

Quote:

Quote:

The use of nitrogen in passenger car tires is nothing but a sleazy cash grab by the retailers.

Did you use a different gauge both times you checked the pressures? Were the tires at the same temperatures both times?

Dave

I must be one of those sleazy cash grab tire retailers because I sell it and install FREE on all tires I sell! Been using it for over 4 or 5 years now, have had great luck. Nitrogen will keep your tires running cooler (longer life), keeps moisture away, less corrisoin between rim and tire bead, less rim leaks (if you have had a Chrysler with chrome rims you know what I mean) and yes air pressure doesn't change as much, It won't stop the air from leaking' but with the larger moducles it slow its down and without the moisture it doesn't change as much. Again I'm only a sleazy cash grab tire dealer, so what do I know after 35+ years in the business

If you're providing it for free, then you're not sleazy!

It's STILL a waste of time, though.

For airplanes that see SEVERE fluctuations in altitude, temperatures, speed and impacts; sure. For passenger car tires ITS A WASTE OF TIME.

Tire temperature is a function of load, deformation and pressure. I seriously doubt tires running nitrogen at the same pressure as air run measureably cooler in a passenger car application.

Moisture in compressed air is a problem that can and should be addressed with an appropriate air dryer and again, nitrogen isn't needed for that either.

Sorry, but most soccer moms are being sold a bill of goods based on some accurate science that makes little to no difference in the real world and they're being charged an extra $5.00 a tire for it usually.

my 2 pennies, again.

Dave

Posted By: deansrr

Re: When they inflate tires..................... - 06/16/09 09:05 PM

I have seen it help, what are you basing your facts on? do you work in this field and know what is really going on?

Posted By: Anonymous

Re: When they inflate tires..................... - 06/16/09 09:40 PM

Quote:

I have seen it help, what are you basing your facts on? do you work in this field and know what is really going on?

D and I both worked in the HVAC field, and although I'm not to the point of engineering, I think he and I both have a pretty good idea of the thermodynamics of gases.

The idea that a drop or two of moisture in a tire can make some magic measurable degree (no pun) of difference in temperature is ridiculous. I WILL agree that dry air might help prevent rust/ corrosion of rims, but that's about it.

The difference in molecule size between O2 and N2 that would make the arguement of "preventing leakage" is again off the mark.

www.getnitrogen.org/pdf/graham.pdf

The other obvious question we all have to ask nowadays is "is this green?"

So let's add up the tremendous amount of energy it takes to extract Nitrogen from wherever you are going to get it, IE liquify air, all the energy it must take to filter purify, etc, and the transportation of VERY heavy bottles and storage containers as opposed to....

just running a compressor and possibly an air dryer/ filter

Posted By: DPelletier

Re: When they inflate tires..................... - 06/17/09 12:39 AM

Quote:

I have seen it help, what are you basing your facts on? do you work in this field and know what is really going on?

I've worked in the automotive industry for many years as well as the HVAC industry as pointed out by my esteemed collegue. I also spent a portion of my youth hanging around my father's tire store and I worked in a garage when I was young......back when there were garages that did all kinds of things like, yes, mount, balance and install tires (we just used air, though!). I also took physics and thermodynamics in University; a change in direction and an opportunity caused me to discontinue my studies before obtaining my engineering degree.

But enough about me;

So, what EXACTLY have you "seen it help?" hmm.... you've measured the temperatures of tires used in identical applications filled with dry compressed air vs. nitrogen? You've run a study with your customers and have checked thier mileage after time and compared the results using air vs. nitrogen on a significantly large cross section to obtain viable statistically significant results? Let's hear what you've learned. I have no problem admitting I'm wrong if you can come up with something factual that dispels my prior contention.

If one car has 35psi in it's tires and one has 30, then yes! all those wonderful claims of increased mileage and lower emmissions and peace on earth are all true! Problem is that you can have the correct tire pressure using AIR.....you just need to check it once in awhile and make sure the pressure is correct. The tires don't care whether they're filled with 80% Nitrogen or 95% Nitrogen, only that they are inflated properly. Oh, and use dry air and you won't have any corrosion issues either.

Dave

some reading;

http://community.discovery.com/eve/forums/a/tpc/f/9701967776/m/2811947799

http://www.cartalk.com/content/columns/Archive/1997/September/05.html

http://blogs.consumerreports.org/cars/2007/10/tires-nitrogen-.html

Posted By: Mopar67Ply

Re: When they inflate tires..................... - 06/17/09 01:58 AM

Try this...

Attached picture 5297481-195-hug.jpg

Posted By: SportF

Re: When they inflate tires..................... - 06/17/09 07:44 PM

All gases, nitrogen, oxygen, hydrogen, all of them expand and contract at the same rate. Its the law of gases, physics 101.

Posted By: patrick

Re: When they inflate tires..................... - 06/17/09 08:50 PM

Quote:

A lot of the tire shops are going to a nitrogen fill rather than compressed air. The theory is that nitrogen does not expand and contract with temp changes like compressed air does. For example blow up a balloon, tie it and put it in the freezer. Take it out an hour later and see that it has shrunk. Leave it out in the sun and it will expand. Supposedly nitrogen will not shrink or expand. I am not a chemist, just relaying what I have been told. Green valve stem caps indicate nitrogen filled tires. It is also compatible with normal compressed air.

nope, Ideal gas law: PV=nRT

P=pressure
V=Volume
n=# moles (molecules) of gas
R= ideal gas law constant
T=temp

increase or decrease temp, keep volume the same, pressure goes up or down. keep pressure the same, volume goes up or down.

air is ~78% nitrogen, ~21% oxygen and the rest water vapor, argon, CO2, etc, etc.

don't remember the physical size of 02 molecules vs. N2 molecules whether or not there's merit there. the main advantage I can see of using compressed nitrogen from supplied cylinders is there is no oxygen to oxidize the rubber from the inside, and no water vapor and oxygen to oxidize the inside of the rim. the no water vapor is probably 99% of the benefit.

Posted By: hemicar1971

Re: When they inflate tires..................... - 06/17/09 08:56 PM

General Motors on most vehicles only uses a P41 Lube on the tires so they will go on the rims without leakage and damage. I will grab the Label of a 45 gallen drum at work and see just what is said on it for application of this lube.