Last night I was riding into a parking garage with a steep decline before the entrance. I hit the bottom of the ramp hard and lost most of the tire pressure in my front tire in a split second. I thought it was a pinch flat or blowout right away so I walked it over to a local bike shop where they had a air hose and was able to air up the tire which held the air and is still inflated to the proper pressure this morning. Does anyone know what may have caused the air loss and subsequent flat?

It is a road bike with racing tires and presta valves. I also check the pressure and fill the tires every couple of days so it wasn't flat already.

  • 1
    If you ride a bit, does the pressure go out immediately/pretty quickly? If not, the only logical way the air could have escaped is through the valve.
    – Batman
    May 10, 2017 at 14:51
  • 3
    Do you run on tubeless tyres?
    – Carel
    May 10, 2017 at 15:00
  • 1
    I do not. Which is why I turned to stack exchange for a possible answer.
    – gyoung1986
    May 10, 2017 at 15:43
  • 3
    Then as @CardMechanic suggests, there may be a puncture that is sealed off by the tyre and that the best thing to do is to take out the inner tube and check it for a hole.
    – Carel
    May 10, 2017 at 17:56
  • 1
    Do you have slime in the tires?
    – paparazzo
    May 10, 2017 at 19:08

1 Answer 1


A tube is a sealed system. If the rubber isn't punctured and the valve is closed, there isn't anywhere that air could have gone all at once like that. The only thing I can think of is maybe you do have a small blowout tire side, and somehow the tube is sitting flush against the tire in such a way that it's holding it closed for now. May be worth taking the tire off and checking the tube itself, being prepared to replace it. Because(in the one in a billion chance that this is what happened), if that did happen, it could be hazardous to keep riding on it.

  • Thank you CardMechanic you hit that on the head. Maybe I should've bought a lotto ticket as well.
    – gyoung1986
    May 11, 2017 at 13:47
  • Wow, literally a one in a billion shot! But it was all that made sense. May 11, 2017 at 14:15
  • This was my first guess. I have had a tube do this before, it was a little wet so it held for a day or 2 before it gave out.
    – BillyNair
    May 11, 2017 at 23:05

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