Originally Posted by Iain.Oglethorpe
Nitrogen has a larger particle/atom than the Oxygen which over time can pass through the tyre carcass, therefore Nitrogen inflated tyres do not deflate over long periods especially if the car in question is stored.
in theory yes, nitrogen has a little advantage over air.
but the nitrogen that is put into car tyres by the machines in tyre shops is processed nitrogen, merely nitrogen rich air.
and all the air isn't taken out of the tyre by vaccuum or anything before the "nitrogen" is put in thereby diluting it even further.
it really isn't worth doing unless you go for pure nitrogen as per the aircraft industry etc..
i know a bloke who works on the typhoons at raf connibgsby up the road.
they have the tyres stored inside a room filled with pure nitrogen before they are fitted, they have to go in there with breathing equipement.
the nitrogen they use is hugely expensive, plus the associated costs with using it.
still doesn't prevent heat build up though.
they have to use infra-red heat reading guns to monitor the tyres after landing, usually have to wait about 90 secs after landing to allow the tyres to cool enough before they are safe enough to approach.
quite a bit different than the stuff peddalled by the fast fit tyre industry..
there may well be a marginal increase in the resistance to pressure drop through the tyre carcass but most pressure loss when wheels are stored is through poor bead sealing, nitrogen doesn't help in that case.