Jim wrote:
> I'd be skeptical...  If I remember Boyle's Law, inert or no, gas
> pressure will increase with temperature.
>
> <http://www.grc.nasa.gov/WWW/K-12/airplane/aboyle.html>
>
> Jim

Yeah...there are only two benefits I can see to filling tires with nitrogen:

- It may bleed out less quickly through the sidewalls.
- It will prevent any fires from starting inside your tires. ;)

Rumor has it that during development of the U-2 spy plane, they tried
filling the tires with helium to reduce weight.  (Every pound saved
meant a notable increase in the aircraft's maximum altitude.)  They
found it wasn't practical because it leaked out through the sidewalls
too fast.