newwallet said:Adam2004 said:Uhhh, filling your tires with Nitrogen is actually very smart. Why? When you fill your tires with air, the current humidity (amount of water in the air) goes into the tire. This means your tire pressure will fluctuate a lot more than you want it to depending on the weather. Nitrogen reduces the variation in tire pressure, increasing tire life and keeping your miles per gallon high.

I think we covered this before. If they're giving 100% unadulterated N2 gas, this is true. But chances are they're not. Any good gas station should be giving you 'air' with very low humidity to avoid precisely the problems you describe. Again, there's not much difference between 89% N2 and 99%, as long as most of that other 11% or 1% is O2 and CO2 and not H20.

TRUE!!

Don't make me bust out the ideal gas equation and the law of partial pressures. Any gas will expand at a high temp. Also, the real difference between an inert N2 molecule and a h20 molecule is the amount of hydrogen bonding in the water. I just can't see that small amount of hydrogen bonding being significant enough in the gas state to account for a detectable difference in the tire, let alone mpg or handling.

thnnwallet said:hellmutt said:douggie said:I wouldn't bother with the hassle. At the speed we're driving, it's not THAT critical if pressure fluctuated while driving.

It's different in racing because they are running at much higher speeds and that every fraction of a second counts.

Apparently you've never had a blowout. You know those people you see on the side of the freeway? It's usually because their tire is flat, and it's usually because the heat of driving (or ambient heat on hot days) expanded the moisture inside the tires, causing it to burst.

You have got to be kidding. Basic science: the "heat" of any tire at highway speeds cannot blow a tire! Look at a steam table. From 5 deg C to 60 deg C at 100% rel humid only causes a Max of 8% increase in presure.

Even over-inflating by 20% cannot blow a modern tire.

Thanks for backing me up with numbers, thnnwallet. It's just common sense that the difference is not that significant to cause an instant blowout. Well, I take that back... unless you over inflated your tires nearly to the MAX pressure stated on the sidewall (while it was cool), then you went driving. The heat would then push it OVER the max pressure and MIGHT cause a blowout.

And yes, I've never had a blowout due to pressure fluctuations. From nails, potholes and other crapp, yes.

"You have got to be kidding. Basic science: the "heat" of any tire at highway speeds cannot blow a tire! Look at a steam table. From 5 deg C to 60 deg C at 100% rel humid only causes a Max of 8% increase in presure.
"

Actually, what happens is if your tire pressure is low, your sidewall tends to flex more. As the sidewall flexes back and forth, back and forth, the heat buildup in the sidewall can cause the side to literally "melt" away. I should know, I've had it happen - at 25mph, my tire lost air from a nail or something. When I stopped (for a smoke break), I looked in my rearview mirror to see smoke rising up. Went to the back of the car (rear wheel drive v8, didn't notice it) and my tire was pretty friggin warm... and the sidewall had a nice crease the whole way around from heating up so much.

Kinda sucked, seeing the tires were 120$ a piece. Oh well.... That's not the point of this thread though.

Just fill up with air and check once a month. And make sure you're not leaking from your valve stems - go buy a valve stem tightener and a 4 pack of valve stems just in case....

arct said:69ragtop said:here is a link for the coffin sales at costco

AJC link

That link is dead. No pun intended.I revived it...

nquinn said:For all of you out there who think Nitrogen is expensive...

The fabrication lab I used to work at bought nitrogen gas for CHEAPER than oxygen. The stuff in NOT expensive.

It's commonly used in tons of manufacturing operations where an inert gas in needed.

Take a look at paintball guys too... many use nitrogen instead of co2 for its stability. The price of fills is about the same.


Nothing you're saying is relevant to the N2 vs. compressed air argument. Pure O2 is very expensive, very flammable and no one would ever consider putting that in a tire. You could put C02 in a tire (in fact, they do put that in bike tires at times, etc), but that tends to have more moisture and would be prone to blow outs. They use N2 in paintball guns because it's easier to regulate and, if I remember correctly, results in fewer broken rounds in the barrel. Of course nitrogen is cheap compared to O2, look at its abundance in the atmosphere. Not to mention you can pull it out of NH4NO3 relatively easily. But compared to compressing some air and making sure its humidity is low? Give me a break.

Edited: for clarification on pronouns.

Well...now we have FW Jokes + FW Deals. Thats another deal in itself....look for a deal and get a free joke .

delta901 said:douggie said:Thanks for backing me up with numbers, thnnwallet. It's just common sense that the difference is not that significant to cause an instant blowout. Well, I take that back... unless you over inflated your tires nearly to the MAX pressure stated on the sidewall (while it was cool), then you went driving. The heat would then push it OVER the max pressure and MIGHT cause a blowout.

And yes, I've never had a blowout due to pressure fluctuations. From nails, potholes and other crapp, yes.

Did you watch those police car chase? What happen at the end? The tire blow-up right?

Dude, we're talking about NORMAL everyday driving conditions. I have nothing to say if you drive like that everyday LOL

If you do burnouts and lots of wheel spinning, the tire temperature/pressure will increase a lot more than just crusing on the highway.

clearanceman said:I heard on the radio that Costco is test marketing coffins. They are trying it in the midwest, Chicago first. There would be a display in the store and you could order a coffin. $799 for any style they have which is actually very inexpensive for what they are. Local Pittsburgh radio guy talked to the vp of Costco about it today. Should change the funeral business a little, there is normally a huge mark up on coffins.

You think I am kidding but I am not.

Good then, this works out great! Fill My coffin with liquid nitrogen, and when a cure is found for whatever kills me, thaw me out and fix me!

love it OP. Great find! Especially for the 1k I just shelled out for my new high performance sports tires.

MillionairesNextDoor said:newwallet said:Adam2004 said:Uhhh, filling your tires with Nitrogen is actually very smart. Why? When you fill your tires with air, the current humidity (amount of water in the air) goes into the tire. This means your tire pressure will fluctuate a lot more than you want it to depending on the weather. Nitrogen reduces the variation in tire pressure, increasing tire life and keeping your miles per gallon high.

I think we covered this before. If they're giving 100% unadulterated N2 gas, this is true. But chances are they're not. Any good gas station should be giving you 'air' with very low humidity to avoid precisely the problems you describe. Again, there's not much difference between 89% N2 and 99%, as long as most of that other 11% or 1% is O2 and CO2 and not H20.

TRUE!!

Don't make me bust out the ideal gas equation and the law of partial pressures. Any gas will expand at a high temp. Also, the real difference between an inert N2 molecule and a h20 molecule is the amount of hydrogen bonding in the water. I just can't see that small amount of hydrogen bonding being significant enough in the gas state to account for a detectable difference in the tire, let alone mpg or handling.

Tell you what, try and bust out the law of partial pressures and the ideal gas eqn. I call your bluff, seems like you fell asleep in the latter half of the lecture on partial pressures. It actually does support the use of nitrogen in tires.

Without going too much into it, just by removing the majority of water vapor from the tire's inside, we get pretty good results. For example, assuming static values for n & V in the ideal gas law, and referenced values for "air" and "water" densities, we can come up with the well known density derived form of Daltons Law of Partial Pressures as applied to :

P=(p1)287T + (p2)455T ; Where (p1) is the density of the "dry" gas and (p2) is the density of water vapor.

Simple algebraic manipulation yields that the pressure and temperature in this compound gas system is related in the following way:

P=[(p1)287 + (p2)455] T

Whereas in an isolated system free of water vapor, pressure and temperature will vary as follows:

p=[(p1)287] T

This shows that when you eliminate water, or in fact ANY other compound with a higher density (mole for mole, gaseous nitrogen has a lower density than water and even oxygen), you will get a lower coefficient in front of the temperature in the equation, thus you end up with a lower fluctuation in pressure.

BTW, you just made yourself look really stupid from this ...

MillionairesNextDoor said:Also, the real difference between an inert N2 molecule and a h20 molecule is the amount of hydrogen bonding in the water. I just can't see that small amount of hydrogen bonding being significant enough in the gas state to account for a detectable difference in the tire, let alone mpg or handling.

Besides the fact that N2, and H2O (O for oxygen not H20 for zero, what ... like twenty hydrogen atoms strung together?), are comprised of TOTALLY DIFFERENT ATOMS, They have almost nothing in common. N2 is a one dimensional, linear, diatomic molecule with 2 or 3 sigma bonds if you have seen its resonance structures. For those who have taken more advanced courses, its bond order is 2.88. It has one effectively non polar bond is a non polar molecule. H2O (Once again O for oxygen not 0) Is a two dimensional, bent, triatomic, planar molecule with two clear polar bonds resulting in an overall molecular dipole. Each hydrogen has one sigma bond with the oxygen, and actual bond orders are around 0.90. I could ger into molecular bonding theory where the differences increase ten fold but I think I've made my point.