I don't think the highlighted comment is true. When you pump up a tire, you are increasing the pressure in the tire, pump hose, and of course the pump cylinder. The air may be "expanding" insofar as the tire volume is expanding as you pump it full of air, but the pressure is increasing in the tire and the attached hose. This leads to increased temperature. Sure, the tire "expands" a bit as you pump it up, but you are not letting the air expand freely forever. Expansion is limited by the fixed volume of the tire inner tube. Eventually the pressure in the tire build up (to 100+psi for road tires).

I've already conducted an experiment to check this out, and you can check it yourself. I've used a gadget in my shop (a "Fieldpiece" refrigerant thermometer) to check the temperature of my bicycle pump under two different scenarios. Scenario 1: pumping with the pump connected to open air; and 2: pumping into a tire.

In both scenarios there was a temperature increase, which was greater when pumping up a tire. The only way to explain the increase in scenario 1 is that the heat was generated by friction in the pump cylinder. If what you claim is true, the temperature should havedecreased due to gas expansion.

Just my 2 cents. Correct me if I'm wrong.