Nitrogen is NOT an inert gas!! Lol
And your tyres will be at lower pressure when cold!
If you heat a gas up it expands, if you cool it it shrinks, ever heard of the Ideal gas law/Boyles law??!!
The term inert may also be applied in a relative sense. For example, molecular nitrogen is inert under ordinary conditions, existing as diatomic molecules, N2. The presence of a very strong triple covalent bond in the N2 molecule renders it unreactive under normal circumstances.
