tdracer, forgive me I may not have spelled it out as clearly as you had but I exerted the same primary reason you had for the use of an inert gas in aircraft tires. At high pressures air can become volatile especially with the addition of heat bringing flammable gasses into the mix from the rubber of a tire that reacts with the compressed air. In the past I had heard of allowable use of compressed air for a leg or two if nitrogen was not available to get it home to a station where nitrogen was available. The long term effects of moisture and oxygen on rubber are common knowledge yet are not the reason for the use of nitrogen in aircraft tyres, only an additional benefit.