Originally Posted by
Sy Reene
Not exactly, but that's the right idea. The sound of escaping air is from the hose mostly. As soon as you remove the the pump head, the valve closes.
No...as SOON as you stop pushing down on the pump handle the valve closes. You go from more air in the pump chamber to more air (pressure) in the tube/tire instantly. NO air pressure is lost when you remove the pump head from a Presta valve.