How To Pump Up Tires With Presta Valve. Engage the pump to inflate your mountain bike tire to your chosen pressure. A typical Presta valve has three parts.
Aug 18 15 at 1007. Cut the tip off a plastic Presta valve cap. Unscrew the screw on the tip of the presta valve.
So if you have a Presta valve tire you either need to get a pump compatible with Presta valves or you get an adapter that fits the valve.
The New Wheel has great videos and guides on how to inflate a tire with a presta or schrader valve. The adapter effectively converts your Presta valve to a Schrader valve so that you can use a traditional air pump to inflate it. Unscrew the cap and loosen the lock nut on the Presta valve. Turn the lock nut on top of the stem counterclockwise until it is loose enough to allow airflow.
