I agree, just use air.
Nitrogen is best for track days as it reduces tire temps.
Too bad there is no one trying to use Helium.
I wonder if that would even work?
Having worked with Helium, it is much more difficult to contain, being a very small, non-reactive atom, is even harder than containing hydrogen. With something like a rubber car tire with a simple low pressure bead seal, your tire will likely be flat in a matter of days.
Thereās a reason that vacuum chambers and many other systems that are designed to be sealed really really well use whatās called āhelium leak testingā to verify seal integrity, which is basically a leak down test where you fill the system with helium gas and measure how slowly the pressure drops.
The reason to use nitrogen in a tire is that it has little to no water vapor and behaves more like an ideal gas than the humid air coming out of a compressor (which can only be dried so much with a dessicant cartridge), so the pressure will change less with temperature. Good for race cars where tire temperatures get pretty toasty because you can run several PSI lower hot pressures for that tiny sliver of extra grip without having your tires go flat when they get cold.
Also, nitrogen gas is basically a waste product of the āair productsā industry that produces stuff like bottled oxygen, liquid nitrogen, welding gasses, etc etc, so itās dirt cheap. For most tire shops, itās cheaper to have nitrogen bottles filled to air up tires than it is to invest in a proper desiccant cartidge setup for their shop air system, or separate small compressors with driers just for filling tires, both of which can get pretty spendy. And the cheap advertising to most consumers that think it must be a good thing.
For a street car the benefit is minimal at best, but if youāre using your own compressor at home, a very small dessicant air drier can be had for pretty cheap.
That said, Nitrogen is really cheap too - itās just the upfront cost of bottle rental, regulator and the extra hoses and fittings that will cost you.