"Al" > wrote in message
. 4...
>> The advantages are said to be that nitrogen diffues through the tire
>> wall about three times slower than oxygen
>
> Utter rubbish. In fact, nitrogen will 'diffuse' faster than oxygen!

Sorry, Al, you are wrong.
Nitrogen (n2) molecules are larger than Oxygen (o2) ones, air is a mix of
primarily n2 and o2, o2 bleeds out of a wheel (beads, valves etc, not
necessarily through the carcass although that also is a factor) at a faster
rate causing a pressure drop.
This same theory is exactly how an on-board oxygen generating system from an
aircraft works, air is passed through a bed of zeolite crystal media, the
larger n2 molecules are trapped in the matrix, allowing an "artificially
enrichened" supply of o2 which is then pressurised for supply as breathing
o2. There are 3 beds, one being back-purged by a small o2 bleed at any given
time ready for its next cycle.

>
>> and that it does not
>> contribute to oxidation of the interior of the tire.
>
> Vulcanised rubber does not oxidise.

Depends on what you class as oxidation, main deterioration of tyres is
caused by ultraviolet light and foreign chemical contact, such as oils and
fuels.

>
> If you believe this crap you'll believe that the earth is flat ;-)
>
> Al.

Ok, then believe an aircraft engineering technician with over 22 years
experience. Or go read up on the subject, a company in the UK called
Normalair Garret might be a good starting point.......
Badger.