the sci guy 

So both my wife and I have presta valves on our bikes, and we have lezyne frame-mount hand pumps. I specifically have this one: https://amzn.com/B005X7AHK8, she has a slightly smaller one. (They have a hose hidden inside you screw on to the valve)

Anyway, it takes us about 30 minutes to add just a little bit of air to the tires: 27 minutes to actually get it so air goes in, 3 minutes to top off all 4 tires.
Yes we have unscrewed the stem thingy at the top to let air in.
What happens is when we screw on the hose and then try to pump but it just doesn't go. It's like pushing the pump handle against a brick wall. OR, it'll just shoot air out from between the hose/valve like it's not sealed. Most it's the former though. We have to fiddle with it - unscrewing it half a turn or down 3/4 or take it on and reset it about 10 times then again trying to dial in the perfect amount.

It only works when you push hard like before and finally there's a little pop/push and then you can pump air into the tire.

Has anyone else had this issue? Is it a presta thing or is it our pumps?
I took it to the LBS once and they had a similar issue briefly but they said we just weren't pushing hard enough on the pump. But seriously I push so hard and nothing happens. I think they got lucky.

HillRider

Presta valves often stick after they have been closed for a while. The standard procedure is to "burp" the tube before you attach the pump by opening the nut and tapping the stem to unstick the valve by allowing a small amount of air to escape. Then attach the pump and it should work fine right away.

BTW, frame pumps are a poor way to top off tires routinely. Buy a good quality floor pump for daily use and limit the frame pumps to emergency road-side flat repair.

Bill Kapaun

+1

FBinNY 

+1 to Hillriders comments.

Burping the valve before pumping is absolutely critical on most valves made in the far east. This was never an issue in the past, but it seems that today's valves use a softer gasket material and they routinely stick closed.

Also, save the hand pump for on the road use, and buy a decent floor pump, preferably with a gauge so you can easily top off at home. The easier it is to pump the tires, the more likely you'll be to do so, and you won't be working harder by riding under inflated tires.

the sci guy 

we will buy a floor pump once we move, it's already planned. right now though that's not my concern because i'm going to go ahead and assume we're going to have the same problem with it.

also we do "burp" the valve before pumping as well. but i do it by using my fingers to push down on the nut. should I tap the top of the valve stem itself instead?

my pump has a schrader valve as well, and i used it to fill up a friends tire while we were riding with zero issues.

FBinNY 

The valves can stick pretty hard, and if you're topping off four tires, your finger may not be too happy afterward. My floor pump has a fairly heavy brass head and I give the valves a quick tap with it. Or you can use anything you like as a pad when pushing with your fingers. There's no rule and the goal is to pop the valve open for as short a time as possible to keep air loss at a minimum. (especially if using a hand pump)

Homebrew01

Doesn't matter how you burp it, as long as it breaks the seal and you hear a quick "pssshhhh" of air come out.

Bill Kapaun

Are you screwing the valve all the way out?
My pump won't push the "pin" unless it's nearly all the way out.

the sci guy 

ok so no problem here.

yes. I've tried screwing the nut all the way to the top where it stops, and a little just below.

at first i was willing to chalk it up to my tires being wonky, but not if it happens with my wifes pump and her tires too. it's got to be something to do with the way the pump works i guess?

Soil_Sampler

it could be the operator?

get a good floor pump and chuck. SKS, Silca,etc.

the sci guy 

pretty sure it's not my fault.
besides, if i do need to use it while out riding because of a flat i don't want to spend 30 minutes trying to get the damn thing to function.

MRT2

I have the Topeak Road Morph and unfortunately, I had to use it the other day as I got a flat. Not as good as a good floor pump, but pumped up my tire to 95 psi in just a minute or two.

FBinNY 

Try burping the valve and seeing if that solves the problem. Some pumps also are sensitive to how far they're pushed down onto the valves, so experiment until you dial it in. I agree that you want a reliable pump on the road, so make sure you clear that hurdle ASAP.

If it still doesn't work well and a stuck valve isn't the issue, then ask a local dealer or friend for help, or scrap the pump. In any case, be aware that mini pumps tend not to be the most effective pumps in the world, so be willing to accept, less than full inflation, but enough to get you home as a workable compromise, or consider a full length pump, or mini combined with a CO2 inflator.

PiLigand

Some thing like this happened to me today. It threw me off for a bit, but I think I may know what's going on in there. Personally, I have a cheap pump without very precise geometry in the nozzle. Rather than hitting the back of the nozzle, as some do, this one goes for a taper in the nozzle that catches that little pin you unscrew on the valve and pushes it forward. I believe this is how most presta nozzles work. The lever is then opened or closed, which engages the cam which clamps down and makes a seal on the valve.

in my case, the imprecise nature of my pump meant that the taper wasn't steep enough to quite catch the unscrewed valve head to depress it. Then, once the cam seal was engaged, it was basically just pumping against the nozzle, not into it. This is the brick wall feeling.

i got around it well enough by unscrewing the valve nub a bit further, and putting just a little pressure on the nozzle lever. This engaged the cam just enough to catch the pin and depress it, at which point I engaged it the rest of the way and the pump worked fine. It sounds to me like this is what is happening in your case. Your pump isn't catching the valve head, so it never opens into the tube. Try moving that lever by about 7 degrees, or just to where to feel the cam's resistance, and then put it on the valve.

cxwrench

The Lezyne pumps are very good. I've had their frame pump and floor pump for years and never had a problem. I work as a professional mechanic and i'm constantly amazed by how hard people make simple things like inflating tires. Don't overthink it.
Open the valve.
Tap it so it's not stuck.
Attach pump head...push it on, then thread it on 'til tight.
Inflate...(wishing you had a floor pump).
Unscrew head.
Close valve.
Ride.
If this takes longer than 1 min per wheel, you're doing it wrong.

the sci guy 

my pump doesn't have a clamp. the hose just threads straight on the valve.
here's a pic

i have felt like it wasn't catching the valve right and pushing down to allow air in myself. see the weird thing is the way it screws on is when you start there is resistance like you're threading it, then it gets loose and can wobble, then gets tight again - this all occurs as you go from top and screwing down. if it's not down enough, the air just shoots out around the valve and you can hear it.

i'm not a moron. i'm not doing it wrong. something else is wrong.

jland

With presta valves the valve stem is not supposed to be pushed in when the air chuck is put on the valve. With schraeder valves, which were designed for automotive use and have a spring loaded valve stem, yes, the pin should be pushed in by the pump head. That's why schraeder air chucks always have central pin and presta don't. In the 80s we had these flimsy plastic Silca frame pumps which would shoot the handle straight out into your chest when the valve stem bottomed out in the pump head... good times...

HillRider

The pump head will thread onto the valve stem using the threads for the plastic dust cap. If your valve stems are smooth above that it will thread it on further until it clears those threads and looses its seal. No, you're not a moron but you are doing something wrong.

PiLigand

Whoops, my bad. I really should have checked out closer what you posted in the original post. I apologize. unfortunately, I can't offer much beyond that. I've never used a thread-on pump. Best of luck, though. I hope one of these knowledgeable people has given you a good answer.

Al1943

Well said.
With presta valves there is no need for any internal part pushing the valve open. The pump's air pressure should open the valve once it has been "burped". I use a Silca pump chuck that has no internal parts other than a rubber grommet that slides down over the valve stem. I use valve stems with no threads. There is nothing other than friction between the rubber and the smooth valve stem holding the pump chuck in place. The valve pops open from the air pressure. I rarely need to burp the valves.

jsharr

I know on my Specialized Air Tool floor pump, I have to be precise in how I attach the head to presta valves or they will not take air. It seems that modern tube valves are more finicky than they were years ago, because I do not recall battling with them like I do now as well. I also burp as others have noted.

phatjonny

I have several pumps, one of my mini pumps is a bit naff. Have you tried borrowing a different pump? Maybe you just need to ditch the ones you have, I believe that is more likely than a technique issue with user.

Update us in the fullness of time?

Al1943

I think that some of the problems and misconceptions expressed in this thread are due to the pump heads on many of the pumps on the market today are designed with the idea that they can be used on either presta or Schrader valves. I think that's not a good idea.

Soil_Sampler

I use co2 with small road pump as backup.