What the small valve is
The thin valve on many road, gravel and performance bikes is called a Presta valve. It is slimmer than a car-style valve, and it has a small nut at the tip that locks the valve closed. That nut is the part that confuses most first-time users, because the valve will not take air until it is loosened.
What you need
- A pump that fits Presta valves, or a pump plus a small Presta-to-Schrader adapter.
- Optionally, a pressure gauge, if your pump does not have one.
For the overall process, including choosing a pressure, see our guide to how to inflate a bike tire properly.
Step-by-step
- Remove the cap if your valve has one.
- Unscrew the small nut counterclockwise until it stops. It stays attached to the valve, so do not try to remove it.
- Press the tip briefly. A short puff of air confirms the valve is free. Valves can stick a little after a time sitting closed.
- Push the pump head on straight. Keep it aligned with the stem, to avoid bending it.
- Lock the head if it has a lever.
- Pump to your chosen pressure, holding the head steady with one hand.
- Release the lever and remove the head with a quick, straight pull.
- Tighten the nut lightly by hand and replace the cap.
Which side of the pump head?
Some floor pump heads have two openings, one for the wider valve and one for the thin one. Use the smaller opening for Presta. Other pumps have a single head that adapts automatically. Check the markings on your pump, or the instructions if there are any. If you use the wrong opening, air will usually leak out around the valve, so it is easy to tell.
Can I use a Presta valve without an adapter?
Yes, if your pump head is made for it. Many modern pumps are. If your pump only fits the wider valve, a small adapter that screws on to the open Presta valve usually solves it. Leave the adapter on the valve if you wish, or remove it after you are finished.
Common problems
- Air escapes when you attach the head: the head may not be fully seated, or the lever may not be locked.
- No air goes in: the nut may still be closed, or the valve core may be stuck. Press the tip again.
- Bent stem: a bent valve can sometimes be gently straightened, though a bent stem may leak. Replace the tube if it does.
- The tip of the valve unscrews with the pump head: the core can loosen in some valves. Tighten it with a valve core tool or small pliers, if your valve has a removable core.
- Tire loses air afterwards: the nut may not be closed, or the tire may be punctured. See how to safely deflate a bike tire for related valve handling and slow-leak tips.
If you have no pump with you, see inflating a bike tire without a pump.
FAQ
Do I need a special pump for a Presta valve? Not necessarily. Many pumps fit both valve types. If yours does not, an adapter is a cheap fix.
Do I need to close the nut after pumping? Closing it lightly helps prevent air from escaping, and is a good habit.
Why does my pump lever not lock? Make sure the head is fully pushed onto the valve before flipping the lever.