help needed with presta valves please!

Paul Turner said:

I've bought a bike with presta valve tubes.
I am used to schrader valves. I went out and bought a large hand
(detonator type) pump, and the shop also gave me this little metal
adaptor, which I can screw into a Schrader valve pump, and should then
work on my presta tubes.

Cut off the chuck at the end of the hose, and replace it with a brass Silca
Presta chuck using a hose clamp.
http://www.sheldonbrown.com/harris/tools-h-z.html#pump

Before pumping, loosen the screw fitting on the valve, and give it a quick
tap to free it up. Now attach the Silca head and pump.

Using this method, I can top off a tire in a few seconds with no lost air.
BTW, I use a silca track pump:
http://tinyurl.com/dtqmz

Art Harris

On 4 Jul 2005 06:35:18 -0700, "Paul Turner" <[email hidden]>

Quoted message said:

I've got a bike problem. I've bought a bike with presta valve tubes.
I am used to schrader valves. I went out and bought a large hand
(detonator type) pump, and the shop also gave me this little metal
adaptor, which I can screw into a Schrader valve pump, and should then
work on my presta tubes.

It's really not that easy. Firsly, when I am using my new pump, I find
it really hard to get an initial reading before I start pumping. And
when I am done, I have REAL trouble pulling the end of the pump off the
valve. I've made sure I take it off lock-mode, but I have to pull
really hard for the thing to come off, which it does in the end, but
lets out LOADS of air (and I often hurt my hand after it hitting to
spokes!).

Can anyone tell me what the problem is here?! and if there are any
really good pumps for the presta valve? I am so used to the Schrader
valve, it was much easier!

The most common type of adapter is a brass bit about half an inch long
which gets *screwed* onto the Presta valve. It's next to impossible
to check the pressure in a Presta-equipped tire in my experience; you
end up getting good at estimating the pressure via thumb and
forefinger.

The inflation procedure for me goes this way:

- Remove dust cap and unscrew adapter from Presta valve (I keep the
adapters on the bike.)

- Loosen Presta valve nut and wiggle stem to break seal.

- Screw adapter back on to Presta valve.

- Clamp tire pump or hose connector on to adapter (if using a hand
pump with a Schrader chuck) and inflate, or use air hose with standard
Schrader valve inflation chuck if inflating from a compressor.

- Disconnect hose or pump from adapter.

- Unscrew adapter, tighten locknut, replace adapter and dust cap,
feel pressure, and ride.
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I've never had much good luck with that adaptor either. It's not a bad
thing to carry for an emergency, but for routine use, it's a pain!

I've not been all that happy with the big brass Silca chucks, either,
but some folks swear by them!

Topeak has a nice "smart head" chuck and hose which can be (somehow)
fitted to your pump. It automagically adapts to either Presta or
Schrader valves. I've not acually used this one, but my pump is a
T-headed Topeak. Topeak has a reputation for great customer service, too.

Paul Turner said:

I've got a bike problem. I've bought a bike with presta valve tubes.
I am used to schrader valves. I went out and bought a large hand
(detonator type) pump, and the shop also gave me this little metal
adaptor, which I can screw into a Schrader valve pump, and should then
work on my presta tubes.

Paul Turner said:

I've got a bike problem. I've bought a bike with presta valve tubes.
I am used to schrader valves. I went out and bought a large hand
(detonator type) pump, and the shop also gave me this little metal
adaptor, which I can screw into a Schrader valve pump, and should then
work on my presta tubes.

It's really not that easy. Firsly, when I am using my new pump, I find
it really hard to get an initial reading before I start pumping.

Loosen lock nut, crack the seal and then put your adaptor on.

Wes

--
Reply to:
Whiskey Echo Sierra Sierra AT Alpha Charlie Echo Golf Romeo Oscar Paul dot Charlie Charlie
Lycos address is a spam trap.

Concur... IMO, this kind of chuck (or head) is THE ONLY WAY TO GO for
home or shop use.

I've an old, reliable floor pump (Husky Zefal, similar to the Silca
model linked to and available at CC) and I upgraded it years ago with
a presta-only valve chuck just like the one pointed out. Now it takes
only a few moments to top off the tires when I'm on the way out the
door -- no fuss, just air.

Just push the chuck over the valve stem (with the valve side of the
tire to the ground), pump to desired pressure, and pull the chuck off.
Any pressure -- no problem.

( http://www.sheldonbrown.com/harris/tools-h-z.html#pump )

No manual actuation of the chuck is required because the internal
rubber bushing (which is under some pre-load compression by the
female-threaded knurled retaining collar) provides an air-tight seal
and sufficient grip around the valve stem to stay in place when you
are pumping. As air pressure on the tube-side of the bushing inceases,
so does the friction exerted by the bushing against the stem
proportionately increase. Thus, you don't have to hold the chuck in
place when inflating the tire and the chuck remains easy to remove
with a gentle tug, even at higher tire pressures.

After hundreds of sessions over a period of years, the original rubber
bushing in the head is looking a little shredded. It still works
perfectly, but I note I can order a replacement bushing with my next
parts procurement from Harris Cyclery.

/* Mykal */

mykal said:

Concur... IMO, this kind of chuck (or head) is THE ONLY WAY TO GO for
home or shop use.

I've an old, reliable floor pump (Husky Zefal, similar to the Silca
model linked to and available at CC) and I upgraded it years ago with
a presta-only valve chuck just like the one pointed out. Now it takes
only a few moments to top off the tires when I'm on the way out the
door -- no fuss, just air.

Just push the chuck over the valve stem (with the valve side of the
tire to the ground), pump to desired pressure, and pull the chuck off.
Any pressure -- no problem.

( http://www.sheldonbrown.com/harris/tools-h-z.html#pump )

No manual actuation of the chuck is required because the internal
rubber bushing (which is under some pre-load compression by the
female-threaded knurled retaining collar) provides an air-tight seal
and sufficient grip around the valve stem to stay in place when you
are pumping. As air pressure on the tube-side of the bushing inceases,
so does the friction exerted by the bushing against the stem
proportionately increase. Thus, you don't have to hold the chuck in
place when inflating the tire and the chuck remains easy to remove
with a gentle tug, even at higher tire pressures.

After hundreds of sessions over a period of years, the original rubber
bushing in the head is looking a little shredded. It still works
perfectly, but I note I can order a replacement bushing with my next
parts procurement from Harris Cyclery.

Good summary. A presta valve can 'stick' closed. Tapping
the valve stem with a finger(after unscrewing the knurled
nut, before pressing the pump head on) is a good habit.

It is not obvious to everyone that installation of the Silca
brass head involves slicing the hose just before whatever
crimp secured your original head. Use a stainless hose
clamp with your new head.

The internal rubber washer is a good fit when new. As it
wears, tighten the end cap to compress the washer.
Overtightening that cap makes sliding the head over your
valve difficult and wears the washer faster - easy does it.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

I second the idea to get a Topeak pump head or a new Topeak pump. I
find mine to be way more easy to use and reliable than the traditional
"press on and pray Silca." The Topeak locks on and you never have to
hold it on with one hand and pump with the other. Delightful customer
service...as mentioned above.

Paul Turner said:

I've got a bike problem. I've bought a bike with presta valve tubes.
I am used to schrader valves. I went out and bought a large hand
(detonator type) pump, and the shop also gave me this little metal
adaptor, which I can screw into a Schrader valve pump, and should then
work on my presta tubes.

It's really not that easy. Firsly, when I am using my new pump, I find
it really hard to get an initial reading before I start pumping. And
when I am done, I have REAL trouble pulling the end of the pump off the
valve. I've made sure I take it off lock-mode, but I have to pull
really hard for the thing to come off, which it does in the end, but
lets out LOADS of air (and I often hurt my hand after it hitting to
spokes!).

Can anyone tell me what the problem is here?! and if there are any
really good pumps for the presta valve? I am so used to the Schrader
valve, it was much easier!

Are you sure your pump is intended for Schrader valves? If it's *really*
hard to pull the pump off the valve, maybe your pump head is intended
for presta valves. If so, you shouldn't be using the adapter.

One of the benefits of the presta valve is that you don't lose any air
when you pull the pump off the valve. I wonder if the escaping air that
you mention is coming from the tube or the pump. Is the tire noticeably
softer after the "loads of air" escape?

As others have mentioned, let a little air out of the tube before you
hook up the pump. That will free up the valve, which tends to get stuck
in place after a while.

--
Dave
dvt at psu dot edu

Don't unscrew the valve all the way, just loosen it enough so air comes out
when you tap the valve. Many connections tend to leak if the valve is
unscrewed too far.
Tom
"dvt" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Paul Turner said:

I've got a bike problem. I've bought a bike with presta valve tubes.
I am used to schrader valves. I went out and bought a large hand
(detonator type) pump, and the shop also gave me this little metal
adaptor, which I can screw into a Schrader valve pump, and should then
work on my presta tubes.

It's really not that easy. Firsly, when I am using my new pump, I find
it really hard to get an initial reading before I start pumping. And
when I am done, I have REAL trouble pulling the end of the pump off the
valve. I've made sure I take it off lock-mode, but I have to pull
really hard for the thing to come off, which it does in the end, but
lets out LOADS of air (and I often hurt my hand after it hitting to
spokes!).

Can anyone tell me what the problem is here?! and if there are any
really good pumps for the presta valve? I am so used to the Schrader
valve, it was much easier!

Are you sure your pump is intended for Schrader valves? If it's *really*
hard to pull the pump off the valve, maybe your pump head is intended for
presta valves. If so, you shouldn't be using the adapter.

One of the benefits of the presta valve is that you don't lose any air
when you pull the pump off the valve. I wonder if the escaping air that
you mention is coming from the tube or the pump. Is the tire noticeably
softer after the "loads of air" escape?

As others have mentioned, let a little air out of the tube before you hook
up the pump. That will free up the valve, which tends to get stuck in
place after a while.

--
Dave
dvt at psu dot edu