You gonna ask a tire salesman about nitrogen? Make sure to get the undercoating put on your tires too


It would be very easy to look up the thermal expansion rate of N2. The lexus dealer told me it was waaaaaaaay less than air so basically don't worry about any pressure change, however, after driving my wife's car 200 mi in 90+ degree weather, I noticed the tires were over-inflated (with pure nitrogen in them from the dealer). Thus, I released some nitrogen from the tires. When it cools off, I will fill them back up with air from my compressor.