What is a Presta Valve? Why Use a Presta Valve?
What is a Presta valve and where are they used? Presta valves are found on higher-end road bikes, mountain bikes, and bikes with narrow rims.
Since the more common Schrader vales have a larger diameter, they require a larger hole in the bike's rim. This larger hole can reduce the overall strength and integrity of the wheel.
Presta valves automatically close when there is pressure in the tube or tire. Presta valves also have a small locknut that must be loosened for the valve to open.
Schrader valves have a spring that keeps them closed at all times unless the pin is being depressed by a pump or other instrument.