If atmospheric pressure is 14.7 PSI at sea level, why is a fully deflated tire at 0 psi

Question

Title basically. Why is a tire with no air at 0 psi if atmospheric pressure is at 14.7. Donee just not count that and the psi gauges compensate for it? Or is something else going on?

In: Mathematics

Answer 1

For the same reason you zero a scale when you put a container on it…so you only get the weight of the contents, not the contents and the container.

You want to know what the pressure is minus the atmosphere. So the gauges come with the atmosphere zero’d out already.