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I have dual system floor pump. When I use it with auto valve it is no brainer to use -- after attaching the pump I get the reading right away, I pump, with each stroke there is small spike in reading, but then pressure readings drops to around pressure in the tube. In other words oscillation is very small and it is easy to read pressure just after attachment or during pumping.

However with presta valve it is completely different story (I was wondering if it is my pump fault, but after some googling I see others face the same problem) -- after attaching the pump I have no reading (i.e. pressure is supposed to be zero), with each stroke there is huge spike in reading the pressure, and then the pressure reading drops to nearly zero again.

Two completely different worlds. I already read some tips about pumping, like slow, smooth, strokes so you could have time to read the peak pressure, but this does not suite me (I already blew one tube with presta valve due to misreading the pressure).

My question is this -- is this problem systematic, by design, or are there some pumps which can give the readings as nicely as for auto valve?

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The problem is your pump's valve chuck. Some valve chucks press the valve's center pin, which lets the pressure from tire to pump and allows reading the pressure. Some other chucks, such as the one you have, do not do that feature. If pressure drops to near zero after every stroke, there may also a leak somewhere in your pump.

Replacement valve chucks are available, you can replace it if you do not want to buy an entire new pump.

  • Thank you. So in short if I see for for auto valve progress with each stroke, and for presta valve with each stroke there is spike, but let's say the reading drops to 0.5 bar and there is simply wild variation between the moment the stroke is in motion, and when it ends, it is simply a pump fault. I.e. replacing the ending (or entire pump) will fix the problem? – greenoldman Sep 6 '15 at 15:34
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    Yes. If your pump works with auto valves replacing the hose end should be enough. I had previously something called "clever-valve" that worked the same with Presta and Schrader. I don't know which other brands would have the same function. – ojs Sep 6 '15 at 15:40

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