I get frustrated with ignorance, and I'm having a very boring day at work. So let me clarrify a few points.
1. There are claims that filling up with N2 reduces pressure fluctuations with temperature changes: At relatively low pressures (air pressures seen in automotive tires are considered low in the world of science, especially for you off-roaders) N2, O2 and even water vapor will all behave as ideal gases, and follow the ideal gas law (PV=nRT). Pressure will increase or decrease to the same extent as the temperature increases or decreases regardless of which gas is in the tire. (Even at 300 psi, there is little deviation from ideality.) Thank you Chem105!
2. More on the temperature claim: N2 and O2 both have essentially the same specific heat capacity (the ability to resist changes in temperature), about 1.0 J/gK. Some will argue the water content of some compressed air is what makes the difference, and it would since the specific heat capacity is double that of the gasses discussed, but it's rare to see water content inside air over 1%. Even a cloud that's ready to rain is only about 2%. So to sum it up, your tires will still experiance the same temperature cycles regardless of the gas you use.
3. Another claim is that Nitrogen will not leak out as easy: The rate of effusion (or diffusion) of a gas through a porous membrane (tire) depends mostly on the molar mass rather than the molecular diameter. N2 is lighter than O2 (28 g/mol vs 32 g/mol) so even IF either gas were to effuse out of the tire, nitrogen would do it more quickly anyway. Luckily, tires are designed not to be porous membranes, and the leaks against the bead are so much more signifigant that they can't really be discussed on the molecular level, so none of this really matters anyway. Let's put it into perspective, N2 and O2 are 29 and 31nm respectively, we'll call that an average of 30nm. That's 30/100,000,000 of a milimeter. Roughly 88,000 times smaller than a human hair.
4. This idea that molecules of any kind act as some sort of wedge contributing to blown beads is also a little bit rediculous too. For goodness sake's people, it's 0.0000003 of a mm! Even IF the nitrogen molecule was considerably bigger than oxygen, it would play no role in preventing a blown bead. This is purely the mechanical forces of pressure at work.
5. Some people claim that the absence of oxygen inside the tire will resist oxidization of the tire: It's true that oxygen is necissary for oxidation, but I'm not sure if I've ever had a tire wear out from the inside out, so I dont see this as a concern. Furthermore, the ozone, O3, in the atmosphere, which is a ground level pollutant, will do a great deal more damage to your tires than the O2 inside the tire. Luckily for us, high levels of O3 are mostly seen in the "smog cities" like Los Angeles.
6. And just to top it all off, and maybe seal the deal for those of you wtill on the fence with this issue. Air is 78% nitrogen, and 21% oxygen, and 1% other crap. So even if you put air in the tire, it's already 78% nitrogen. And the real kicker is that many of the so called nitrogen generators often only produce 90% nitrogen anyway! So you're only getting 12% more nitrogen anyway!
This concept is so rediculous it makes my head hurt.
I find no reason to believe that N2 is going to produce a "better ride" or "better handling".
The bottom line is that for general passenger car tires or truck tires there is nothing to be gained by using nitrogen rather than air. The biggest gain will be seen in profits by the companies that sell nitrogen handling equipment and the tire merchants that appeal to ignorant customers. And who is the biggest loser? Yep, you!
Topic: Filling tires with nitrogen? (Read 2828 times)