# Problems inflating tires with Presta valves



## utente (Oct 10, 2004)

Just got a pump with a Presta valve on eBay. The pump seems to work great but the air isn't gong into the tires. The pump doesn't have a lever to lock the head onto the tire valve and I must be doing something wrong. Any trick to this?


(n.b. I tried doing a Search but kept getting error messages that the Search function wasn't working.)


----------



## CBar (Oct 26, 2004)

Assuming you're unscrewing the little lock on top of the Presta valve first, how does the pump stay connected to the valve without a locking mechanism of some sort? Are you sure you have a Presta adaptable pump? Maybe there is an adjuster on the pump that switches between Schraeder and Presta? Perhaps consider getting one with a lock, like a Park. Mine works great.


----------



## utente (Oct 10, 2004)

It's a Silca pump and doesn't have a way to lock onto the tire valve. As far as I can tell it is set up for Presta. The valve stem does fit into the pump head, just doesn't lock on.

I know that it's something simple but I just can't figure out what I'm doing wrong.


----------



## Cory (Jan 29, 2004)

*That's why I gave up on Silca pumps*

When I started cycling seriously, in the '70s, everybody said Silca pumps were the hot tip. I bought one with my first bike, and I never could master the thing. I don't remember the details--somebody will, I'm sure--but I think you're right that there's no locking device. You had to hold the thing on the valve against the air pressure. I exploded two pumps, literally blew them into pieces, when I pushed the chuck onto the valve. The rush of air blew the handle back at 90 or so psi, and when it hit the end of its travel, the plastic barrel exploded. I eventually learned to work the things a little, but the Zefal hpX cost about the same and it's absolutely foolproof. I used my first one for 15 years before I ran over it with the car, and I'm still on the second one.


----------



## TurboTurtle (Feb 4, 2004)

utente said:


> It's a Silca pump and doesn't have a way to lock onto the tire valve. As far as I can tell it is set up for Presta. The valve stem does fit into the pump head, just doesn't lock on.
> 
> I know that it's something simple but I just can't figure out what I'm doing wrong.


Have you been succesful with other pumps and Presta valves? - TF


----------



## utente (Oct 10, 2004)

TurboTurtle-- it's sad to admit but, yes, I've had trouble with other pumps. Never seemed to get the hang of pumps that lock onto the valve. Even broke a Presta valve recently and had to replace the tube. Anyway, with the pumps that lock on I was able to inflate the tires after a little practice, but I'm still unsure about it and have some trouble.

I thought that the Silca might be easier. It gets such good reviews here, and I figured that I wouldn't have to fool around with the lock.

Maybe there's a trick to this that I'm just not getting.


----------



## utente (Oct 10, 2004)

Cory- well, I feel a little better that I'm not the only one who's had trouble with the pump. It gets such great reviews that I figured that it would be easy to use. 

I still think that I'm doing something wrong and that it's not the pump's fault. I just have to find out what I'm doing wrong.


----------



## CFBlue (Jun 28, 1999)

I may get slammed for saying this, but I have to start with the obvious. Are you letting a little air out of your tires before you try to pump them up? The valves do get a little bit stuck sometimes.


----------



## QuiQuaeQuod (Jan 24, 2003)

I used silcas for years, but they are a bit of a pain. Light, sure. They work, sure. But a PITA. I am now riding with an zefal HPx. Anyway, back to the silca.

First, unscrew the presta valve, and give it a tap to free it. Next orient the wheel with the valve stem at 12 o'clock. Either on the bike or off. Then you push the pump onto the valve. Put your index finger behind the pump head (think of it as a trigger) and wrap your thumb over the top of the tire. If the tire is totally flat, you can use your thumb to press the stem into the pump head. 

Pump. Your index finger and thumb counter the pumping motion, keeping everything in place.

That should do the trick for you.


----------



## utente (Oct 10, 2004)

BBJ- you won't get slammed from ME for stating the obvious. I know that there's an obvious solution and if I keep trying I'll figure it out (before destroying a couple of valves in the process, I hope). But, meanwhile I appreciate any help I can get. I'd really like to get back on the bike.


----------



## utente (Oct 10, 2004)

It's a floor pump, which should make it easier to use. I have unscrewed the valve cap, and used my thumb against the tire (which IS totally flat by now, after my inept tries at inflating). I will try it when I get home tonight, and try tapping the valve to make sure that it's not stuck.


----------



## QuiQuaeQuod (Jan 24, 2003)

d'oh! My bad! After reading Cory's post I assumed it was a frame pump. I've never actually sprung for a silca floor pump, but I have used them. Unfortunately, I don't have intimate knowledge of the pump construction so I am just going to have to make some guesses.

Take a look at the chuck, the part that goes on the valve. Inside is a rubber bit, and that is the bit that holds the hose on the valve. Two things can happen with these. First, they can get chewed up, but that makes it harder to get them on and off. Second, they can get worn. It is an easy thing to replace, which you might need to do.

One more thing. Check the pump head and make sure all the parts are screwed together tightly. IIRC when the head screws together it compresses the rubber bit, which bulges out a bit, and that makes for a tight seal on the valve. If the pump head is loose, it can stop keep a tight seal from forming.

All this assumes that the pump is actually pushing air. Hold your thumb over the chuck and pump the handle. Does air pressure build up? Or does the handle keep moving? If it does not build up pressure you might need to grease/replace the washer on the plunger. Simple to do.

I hope this helps.


----------



## utente (Oct 10, 2004)

I should have been more clear. It's a Silca Pista floor pump. It does push air and seems to have good pressure, although I have to push the handle down about 1/2 way before it builds up pressure. But that doesn't seem to be the problem. It's getting a good seal. I already took the head apart (and put it back together), but that didn't do anything (either good or bad).

Also-- any idea whether the head is reversible to use with a Schraeder valve?


----------



## soman (Jun 15, 2005)

utente said:


> Just got a pump with a Presta valve on eBay. The pump seems to work great but the air isn't gong into the tires. The pump doesn't have a lever to lock the head onto the tire valve and I must be doing something wrong. Any trick to this?
> 
> 
> (n.b. I tried doing a Search but kept getting error messages that the Search function wasn't working.)


You have to twist it to lock on the valve


----------



## utente (Oct 10, 2004)

*Oh!*

Never even thought of that! Can't wait to get home to try it. Thanks to all of you.


----------



## Kerry Irons (Feb 25, 2002)

*Not so*



soman said:


> You have to twist it to lock on the valve


There is no reason to twist it. I've used Silca pump heads for nearly 40 years and never done this. 

General guidance would be that if there is air escaping from the pump head when you hit the down stroke, then you either need to replace the rubber grommet in the pump head or at least tighten the outer section that holds the grommet in place. My first guess on your problem is either a frozen valve or that you didn't unscrew the valve. Since you've provided absolutely no information describing the problem in detail, it's really hard to say.

BTW, the standard Silca head cannot be used with Schraeder valves. If you have one that can be used with S valves, that may be part of your problem. That pump head from Silca never worked very well.


----------



## Guest (Jul 14, 2005)

*Burp the valve*

It sounds like the pressure is building in the pump, but not going into the tire. Air won't go into the tire if the vavle in the stem doesn't move. There are two reasons it won't move. One is the nut on the top of the stem wasn't loosened (this should be obvious). The second is the valve is stuck. To unstick the valve just push it down (burp it) and let some air out.


----------



## utente (Oct 10, 2004)

Kerry adn dstahl-- I unscrewed the cap on the stem and pushed in the valve stem to be sure that it's not stuck. The grommet looks ok (but who knows for sure?) and the cap is tight on the head. Still can't get air into the tire and I know that I'm doing something wrong but still don't know for sure. Iìll see if I can locate a new grommet just to be sure, but it looks ok. Still think it's me and not the pump.


----------



## Scot_Gore (Jan 25, 2002)

utente said:


> Kerry adn dstahl-- I unscrewed the cap on the stem and pushed in the valve stem to be sure that it's not stuck. The grommet looks ok (but who knows for sure?) and the cap is tight on the head. Still can't get air into the tire and I know that I'm doing something wrong but still don't know for sure. Iìll see if I can locate a new grommet just to be sure, but it looks ok. Still think it's me and not the pump.


How's the rubber grommet look, if it's frayed and worn you won't get a good seal on the valve stem. Unscrew the the cap and see how it looks. Also, as I recall it's possible to switch the rubber around and still be able to get the cap on. If it's there backwards, it won't work. As Kerry said, it's not absolutely nessesary to twist the head once it's on the valve stem, but it won't hurt much either. It will shorten the life of the rubber grommet a little, but I wouldn't sweat it too much. 

I sometimes wet my valve head with a little spit. Does it help....maybe. 

Something to try. Put some dishwashing soap on the valve stem. Drop the head on and pump. If you don't have a good seal, you'll blow bubbles. Where the bubbles appear might help you diagnose your problem. If you don't get any bubbles, well, that tells you something too.

HTH
Scot


----------



## utente (Oct 10, 2004)

Scot-

I took apart the pump head and now at least I see how it works. I took the grommet out of the head and pushed it down onto the valve and it locked right on, without a problem. Now I can see that, if the grommet locks on properly, it should make a good tight seal.

But--- when I re-assembled the head (and trying the grommet in both directions), the tire valve doesn't reach the grommet. Don't know why, but it doesn't. 

I even tried it with a brand new tire straight out of the box, and still it doens't reach. Can't figure out why.

The plastic "pin" inside the pump head hits the valve stem, but the grommet doesn't reach the valve stem. So, it seems that the air is going around the stem.

It seems that a longer grommet would work, but I assume that it's a standard size and that a longer one wouldn't fit inside the head.

Any ideas? This is getting ridiculous. I'm dying to be able to ride!


----------



## CFBlue (Jun 28, 1999)

It sounds like you are trying to put a schrader pump head on a presta valve stem. On my pump, there is no little plastic piece that hits the cap on the valve stem. Air pressure pushes the cap down and lets the air into the tire. Can you take a picture of the parts in the pump head? That might help Kerry Irons or someone with more experience with that particular kind of pump tell you how to fix it.


----------



## Slow Eddie (Jun 28, 2004)

*Post a pic?*

Hi Utente,

What exactly does the pump head look like? Silca has sold the Pista with several different heads over the years - some were Presta only, some were Presta/Schrader compatible. Of those, some had reversible parts inside the pump head that made it fit one or the other, and some had threaded pieces that screwed or unscrewed to the exterior of the pump head to make it fit the valve. I agree with BBJ - sounds like you might have reversed some, but not all, of the parts in the pump head, so the hole for the Presta valve is the right size, but you run into the pin that's supposed to depress the spring on the inside of a Schrader valve.


----------



## Scot_Gore (Jan 25, 2002)

*This One ?*



utente said:


> Scot-
> 
> I took apart the pump head and now at least I see how it works. I took the grommet out of the head and pushed it down onto the valve and it locked right on, without a problem. Now I can see that, if the grommet locks on properly, it should make a good tight seal.
> 
> ...


I've been operating under the assumption that this is the Pump Head you are working with. I started to think that's a bad assumption. Reply back and let us know.
Scot


----------



## utente (Oct 10, 2004)

*Fixed!*

Scot-
my pump head looks a little different. Might be an older model. Anyway, it's similar, but has a second knurled ring right above where the head fits into the hose.

Anyway, what's been keeping it from making a seal is a protrusion (like a pin) on a nylon piece that sits behind the grommet. The pin keeps the valve stem from reaching the grommet properly.

So-- I removed that piece, and it worked great. Next, I tried it again but with the piece reversed, so that the pin faces inward. Worked also. 

I looked up the manual on the Silca website. Wasn't exactly the same, but it seems to me that the nylon piece with the protruding pin is a Schraeder chuck. Apparently the pin pushes in the metal pin at the center of a Schraeder valve, and that's what was preventing the seal.

Seems that the head is reversible, and was set up for Schraeder. Nevertheless, it works great now. 

Once I got that figured out, it does seem to be a good pump. Inflated the tires very fast and with no aggravation.

Does that diagnosis seem right to you?


----------



## Scot_Gore (Jan 25, 2002)

*Good to hear*



utente said:


> Scot-
> my pump head looks a little different. Might be an older model. Anyway, it's similar, but has a second knurled ring right above where the head fits into the hose.
> 
> Anyway, what's been keeping it from making a seal is a protrusion (like a pin) on a nylon piece that sits behind the grommet. The pin keeps the valve stem from reaching the grommet properly.
> ...


Ride On !!!


----------



## utente (Oct 10, 2004)

*Thanks for all the help, guys!*

I knew that it would be a simple solution. It usually is, but you never know when you'll figure it out. Finally, I can ride again!


----------

