I have been debating on having my local Big-O fill my tires with nitrogen. The primary reason I am interested in doing this is to control pressure swings during spirited driving. My tires consistently will reach 4-8+ lbs, and I can tell a difference in traction & handling.

My sole question is this; for those that HAVE had nitrogen placed in their tires, has it helped to reduce pressure swings?

Thanks.

 

Unlike air (which is about 70 percent nitrogen) pure nitrogen will not expand or contract with heat or cold. Planes use it since they can experience big changes in temps. The molecules in pure nitrogen are also smaller than air so leakage is minimal. If you can get it, it can only help. There is no known downside.
Pressure swings will be minimal.

 

Wouldn't smaller molecules be able to leak out more easily?

Did a little follow-up research.....

"Molecular size is a bit tricky. As a quick comparison, we can use the covalent radius defined as 1/2 the distance between to identical covalently bonding nuclei. This is measured in picometers (1 pm= 1x 10-12 m). Nitrogen's covalent radius is 73pm so the length of a nitrogen molecule ought to be 4 X 75pm or 300 pm. A molecule of oxygen ought to be just a shade smaller 4 X 73pm or 292pm. So an oxygen molecule ought to be a little less than 3% smaller than a nitrogen molecule."

 

This is what I was hoping for, but so far, the poll results show that those that have nitrogen have NOT noticed a reduction in pressure swings.

 

Maybe it is just me, but this whole pure nitrogen thing feels like a scam to me, just like bottled water.

Air is mostly nitrogen. The differences cannot be significant.

Nitrogen absolutely DOES expand and contract with heat changes, just like any other gas.

 

I don't have it and have noticed no air pressure swings. Just normal increase in pressure as the tire warms.

 

I am with you, but it would be worth it (to me at least) if hot tire pressure increases are cut by say 50%.

 

Junk science.

You may have learned more by expanding your poll to include other options/experiences.

 

Yes, but this is generally adverse to traction & handling, especially when the rear tires get in the 38 PSI range (up from 30 cold).

Again, not to drift off topic, but I am simply trying to validate that nitrogen does/does not significantly reduce hot-tire pressure increases.

 

Such as?

 

Just answer the poll people.....

 

If there was an option:

"wouldn't throw my money away", I WOULD have answered the poll

 

well there isn't....

 

Air is 78% or so nitrogen so the expansion difference between regular air and pure nitrogen is minimal at best and of no real significance. What is different is that depending on where you live, the time of year and the moisture traps on your compressor you may get a large amount of water vapor mixed with regular compressed air. This, when heated or cooled, is what creates a significant differential in pressure change with nitrogen vs regular air. Bottled nitrogen is water vapor free.

If you are racing maybe the pressure change with temperature is of some significance, for the street is just doesn't matter. All the people I race against (drag racing) use regular old air as it is easier to get and free. Since everyone checks tire pressure air right before each run anyway temperature stability is not very important.

Actually you can get the same performance with regular old compressed air by removing the moisture. This can be done is a number of ways. A friend of mine I race against got a drier from the air brake system of a over the road tractor and uses if on the output of his compressor. His pressure change with temperature is the same as the gas from a nitrogen bottle.

The bottom line is for a street driven car using nitrogen to fill the tires is just hype with no significant benefit except to the store who sold you either the nitrogen bottle or the tire fill.

 

N is, as most components of air, a perfect gas, meaning it satisfies the VP=nRT gas law. Therefore, its pressure is subjected to the same swings as dry air. The keyword here is "dry." If the air has water vapor then it will expand differently. It is important to fill with dry air. I stick with air and run my compressor a couple of minutes to dry the air before filling or checking pressures.

I also wonder what is the purity of N in a N-filled tire. They fill it with N on tires that already contain air... they do not fully evacuate the air prior to filling with N.

 

Where did you get this information? Nitrogen, just like every gas will expand when heated. The ideal gas law, while not perfect for real world situations, still applies to nitrogen.

 

Nitrogen fill.......

 

The difference in thermal expansion of gases is in relation to the amount of gas in a given volume at a given pressure. This is what the n (how many moles)in the ideal gas law is.

This is of no practical significance with regular air vs pure nitrogen. What is important if you want more constant pressure vs temperature change is the water vapor content in the air as has been previously stated by a few including me.

 

I use seasonal tire air from KaleCoAuto, it's much better than nitrogen.

http://kalecoauto.com/index.php?main...products_id=45

I also picked up some of their blinker fluid, it rocks.

 

No thanks. Bad science...