Why nitrogen?

Nomen Nescio wrote in
:

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From: "Viperdoc"

The thread on brakes raised a question from the past- why nitrogen in
the tires of big jets and heavies? Air is around 78% nitrogen anyway,
and the coefficient of expansion of the remaining 20% that's oxygen
can't make that much difference in volume.

Why not just use dry air?

1) It's AVIATION
2) Nitrogen is more expensive


Asked a grease monkey friend there a few minutes ago.
He says that O2 under pressure is considerably more reactive than it is at
normal atmospheric pressures. So the main reason is to prevent oxidation of
tires and seals. A secondary consideation is detonation in oleos.

Bertie