Why does a tyre get hot during inflation

Looking again at Equation (3.5), AU = q + w, we see that if q = 0 and w increases (w is positive), then AU increases. This increase in AU explains why the temperature of the gas in the tyre increases. 

Let us return to the assertion that q is zero, which implies that the system is energetically closed, i.e. that no energy can enter or leave the tyre. This statement is not wholly true because the temperature of the gas within the tyre will equilibrate eventually with the rubber of the tyre, and hence with the outside air, so the tyre becomes cooler in accordance with the minus-oneth and zeroth laws of thermodynamics. But the rubber with which tyre is made is a fairly good thermal insulator, and equilibration is slow. We then make the good approximation that the system is closed, energetically. We say the change in energy is adiabatic. 

In fact, a truly adiabatic system cannot be attained, since even the most insulatory materials will slowly conduct heat. The best approximations are devices such as a Dewar flask (sometimes called a vacuum flask ). 

A thermodynamic process is adiabatic if it occurs within a (conceptual) boundary across which no energy can flow. 

The temperature of a tyre also increases when inflated, and is caused by interparticle interactions forming see p. 59. 

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