nah, I've certainly asked dumber ones. I've often wondered how much air escapes when I remove the pump, but I don't think they've ever felt squishy. I did stop using the crack pipe and valve extenders (the ones that don't move the valve core) becuase I didn't think I was getting enough air in the tire. I bend the valve out of the disk to pump with a regular pump head. Sorry I can't answer this one.

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Check it with another pump. You shouldn't be losing any air when you take off the pump, so any problems would be with the gauge on your pump. The presta valves should close in between each stroke of the pump. You can probably hear them 'clicking' open while you pump. The rush of air you hear when you take the pump off, is just the pressurized air in the hose. The head on my pump has a pressure release button to let that air out before you take the head off.

I have a (relatively) cheap floor pump from Performance bike, and when I finish pumping up my tires, usually to around 110 psi, I double check with my Accugage, and the pressures are identical.

Here's something to think about: Is it possible that you are attaching the pump to the tire, but not enough that it presses the presta valve in? In such a case, the pressure builds up in the pump hose, and when you release it, you get the big Whoosh! of the pressure being released. I would occasionally have that happen with my old wheels because they were semi-aero, and the short valve stems made it difficult to attach the pump to them.

Do yourself a favor. Buy an Accugage or other good quality tire gauge(around $15), and never worry about your tire pressure being correct again.

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I've noticed that too. My solution. Pump it up until it says like 140 (anything you know will be hire than whats in the tire), then wiggle the pump head and value around little until you hear the valve "Click" open. Then check the pressure, pump it up to what its supposed to be then remove. Like the post above me, the air you hear escaping after releasing the pump head is air from the hose not the tire.

I found another solution (every once in a while I don't stick it on there far enough too) is to tap the head of the presta valve before putting the pump head onto the valve. I get a little whooosh of air coming out (1-2psi loss maybe) but it guarantees that air will be going into the tire instead of just building up in the hose. It takes a little practice to figure out how much pressure from tapping your index finger on the top of the valve, but it works 100% of the time. I also have an old Zefal pressure gauge and it always reads within 1-2psi of the pump's reading.

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I do the same thing by giving it a push before attaching the pump.

I am also glad that I am not the only one who never seats the pump correctly on the first try. It almost always takes about 2 or 3 pumps and then I hear a "twang" and I start pumping air into the tube at that point.

Is there a valve extender on the wheels? It sounds to me like you are trying to pump up the tire with the valve closed down. Your pump will read a nice high number because that is the pressure in the hose, but if the valve is screwed down a ways, not much air is going into the tire.

Before you put on a valve extender you want to open the valve all the way up and give it a good twist into the open position - that way it won't vibrate shut over time. (this of course applies to extenders that don't have that extra core thing in them to get in the way)

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Andy Tetmeyer (I work at HED)

I have a Topeak "Air Hammer" good to 200 psi. It has the bleed valve in the head so you only bleed off the air in the hose and the valve seats right away, although using my other conventional pump doesn't seem to let out any more air either it just didn't pump to a high enough pressure.

Amazingly, that worked! Thanks!

Herschel34,

One other issue. The accuracy of pressure gauges in floor pumps is all over the board. Even within the same model of pump. Get an accurate tire pressure gauge and calibrate your floor pump pressure gauge. My Presta Pista pump gauge is off by 17 lbs when it reads 170 lbs. Its really only 153 lbs. This too, could be an issue. My Blackburn Track Pro-4 pump is right on with pressure readings..

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Ben Cline


Better to aspire to Greatness and fail, than to not challenge one's self at all, and succeed.