I've watched several youtube videos on inflating bike tires. i have presta valves on mine.

When I the top is screwed completely on it works but i'm told this is just pressurizing the inside of my pump. When I unscrew the top to open the valve, the tire doesn't inflate at all. What am I doing wrong?

After opening the valve, I put the pump on the stem and push all the way down with the switch perpendicular. In this position I can hear air coming out of the tire.

Then I put the switch up so that it's parallel to the valve and the rest of the pump piece. Then I can hear air stop leaking and it seems ready to pump.

However, when I actually pump to put air in I can hear the air going everywhere except in my tire. What am I doing wrong?

  • 2
    Are you sure you're pushing the switch the right way? some pictures of what you're doing may help.
    – Batman
    Commented Aug 20, 2015 at 22:44
  • Well, like @Batman said, some pictures might be of help here. Also, are you sure that your pump is compatible with presta valves?
    – Weirix
    Commented Aug 21, 2015 at 0:00
  • The pump model also would help.
    – Batman
    Commented Aug 21, 2015 at 0:08
  • After you unscrew the knurled screw on top of the valve, tap it with your finger to release a puff of air. Sometimes the rubber gasket inside the valve sticks, and doing this frees it. And if you hear air escaping as you pump you do not have the chuck properly attached. Sometimes you need to screw the outer collar tighter to adjust it, and there are other things that can go wrong as well. (I had my chuck go bad a couple of years back when the pin holding the lever worked loose, eg.) Commented Aug 21, 2015 at 12:35

2 Answers 2


Practice with a spare tube outside of the tyre. You'll see it start to inflate on one or two pumps.

Could it be the pump you're using locks-on the other way? When its clamped down you should not be able to feel air moving out the end, around the valve.

Possibly your pump is a schrader-only style? There are wee thread-on adapters that let you use a schrader (car valve) fitting on a presta bike valve. They also work as caps to protect the valve.

  • 1
    Some chucks require you to disassemble them and reverse a piece inside to convert from Schrader to Presta. Commented Aug 21, 2015 at 12:36

Sounds like your pump fitting is in schrader configuration. Locate the pump instructions and verify/modify the pump-head.

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