Nitrogen has been used in Formula one cars for some years
and other high speed tyre applications such as aircraft tyres
according to the sales pitch.
The benefits are very low pressure loss (larger molecules)
cooler running giving up to 25% lower wear, 5% better fuel
consumption and quieter running.
At £1.75 ($3) per tyre inflation cost (they say at least 3 months
between top-ups) it's worth a try.
It's only just hit the market over here so little user feed-back so far.
We'll see.
Sounds like you were sold a bill of goods.
The only benefits for the average vehicle is the
resistance to corrosion of wheels and deterioration
of the tire construction through removing any available
Oxygen. Apparently this corrosion can also contribute to
the debris which causes the valves to jam partly open
and leak.
Trucks use Nitrogen to increase carcass life by slowing
the effects of deterioration. Car tires rarely last
long enough for this to be a problem. For the Model A
which gets driven a couple of hundred kms a year, maybe
this is a good thing.
Nitrogen is used in racing because it eliminates water
from the gas in the tire and creates more stable and predictable
pressures, which is vital for peak performance.
Warm humid climates can contain as much as 6% water vapour.
I have seen no evidence that tires run cooler or quieter.
Air is mostly Nitrogen, so clearly the size of the molecules
is the same.
Air by volume
Nitrogen N2 78.084 %
Oxygen O2 20.9476 %
Argon Ar 0.934 %
Carbon Dioxide CO2 0.0314 %
Neon Ne 0.001818 %
Methane CH4 0.0002 %
Helium He 0.000524 %
Krypton Kr 0.000114 %
Hydrogen H2 0.00005 %
Xenon Xe 0.0000087 %
