Science Question!! quick!!15點~

the gas has volume
it occupies the space inside the tyre
with this "outward" force, or tension
the tyre is inflated

This is because when you set the gauge to 34 psi , if the pressure in the tyre is less than 34 psi , the gas will be pumped into the tyre , when the tyre reaches 34 psi , no gas will pumped into it . Always gases move from high pressure to low pressure .