On the topic of presta valves

[jtaylor]

"Roy Zipris" <[email protected]> wrote in message
news:[email protected]...
> I don't recall where I heard about this technique, but I have tried it
> once or twice with no problems: hold the tire with the valve at the
> top, and simply let the tire dangle freely as you pump. You just need
> to support everything with one hand at near the valve/pump end.

Can be trouble if there's a cycle attached to the tyre; if so, better to
lean it against something.

 

[dvt]

Roy Zipris wrote:
> I don't recall where I heard about this technique, but I have tried it
> once or twice with no problems: hold the tire with the valve at the
> top, and simply let the tire dangle freely as you pump. You just need
> to support everything with one hand at near the valve/pump end. Seemed
> to work fine.

That's how I recommend doing it. Make sure the wheel is out of the bike,
as jtaylor noted. And I think it works best if you have the nut on the
stem. This method seems to reduce my incidence of failed stems compared
to any other technique I've tried.

--
Dave
dvt at psu dot edu

Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)

 

[Roy Zipris]

I took it for granted that it was understood that you "dangle" the
wheel while it is removed from the frame...although it is an amusing
image to think of someone, perhaps misled by my description, omitting
this step!

 

[Blair P. Houghton]

jtaylor wrote:
> Can be trouble if there's a cycle attached to the tyre; if so, better to
> lean it against something.

How hard is it to stand over the top tube while pumping a tire up?

--Blair

 

[[email protected]]

On Fri, 11 Aug 2006 03:33:22 -0600, Franz Bestuchev
<[email protected]> wrote:

>[email protected] wrote:
>> On Tue, 01 Aug 2006 04:18:24 GMT, "Chuck Davis"
>> <[email protected]> wrote:
>>
>>> <[email protected]> wrote in message
>>> news:[email protected]...
>>>> ...
>>>> After reading all the praise for the Topeak, I reluctantly concluded
>>>> that my trusty, shorter, no-hose, no t-handle, no foot-support Zefal
>>>> mini-pump was outmoded rubbish (despite its gauge) and bought a
>>>> Topeak. It's just a little too long to fit easily in my frame bag, so
>>>> I used the handy quick-release single frame-clip--works fine.
>>>> ....
>>>> Cheers,
>>>>
>>>> Carl Fogel
>>> Could you explain how the frame clip works? It's not obvious in the clip
>>> parts pictures.
>>>
>>> Thanks.
>>>
>>> Chuck Davis
>>
>> Dear Chuck,
>>
>> A heavy adjustable plastic hose-clamp secures a small plastic platform
>> to anything smaller than an elephant's trunk--preferably a frame tube.
>>
>> It's just like a metal hose clamp, with a big cross-point screw that
>> engages //// holes in the strip.
>>
>> A custom plastic collar with the mate to the platform tightens around
>> the aluminum pump body with a 2.5mm allen head screw.
>>
>> The plastic platform on the pump slides sideways into the plastic
>> platform on the frame. A stiff plastic tab engages and holds it nicely
>> in place. Push the tab down with a thumb, and the pump slides out
>> sideways.
>>
>> If the clip busts, you can buy a replacement clip. Here's a picture:
>>
>> http://www.triathlete.com/store/product.php?id=34589
>>
>> The 2.5mm screw is the gold blob on the left, and tightens that piece
>> onto the aluminum pump. You can see the release tab on it, pointing up
>> and to the viewer's right.
>>
>> Trim the excess off the hose clamp, and you're done.
>>
>> Mine doesn't rattle. The hose is swivel-mounted at the base, but
>> doesn't dangle--the far end with the Presta/Schrader connector clips
>> into a little holder.
>>
>> You can mount it pretty much in any position, top-tube, seat-tube, or
>> down-tube, where I put mine. Hell, you could probably put it on the
>> steering tube or one of the stays with a bit of fuss.
>>
>
>I bought the same pump after reading on here. I have to disagree, the
>*clip* itself is rubbish. The original clip's excess length that I had
>not trimmed all the way back literally shattered like a rose in liquid
>nitrogen. A day later the rest of the band broke just as I was mounting
>the pump back onto the bike after riding the bus to an adjacent town.
>
>In the picture you can see the band on the right. I went to a hardware
>store hoping I could find some sort of replacement strap for the "shoe".
>No luck because they didn't have one of sufficient diameter.
>
>I think it was the cold as it was ~45°F when I was having these
>failures. My first attempts to contact support were ignored, but my
>second attempt was promptly responded to. At the time I found somewhere
>on their site where several different mounting clips were available. I
>asked the support site if it would be possible for me to get one of
>those instead and pay for 2 more as I would like to move the pump
>between bikes.
>
>They didn't respond to that at all, but they were kind enough to send me
>3 complete mounting brackets for free. So when it starts getting cold
>again I'll see. It's clear that the mounting bracket uses a different
>kind of plastic, one without the "fibers(?)" that I find on other parts
>of the pump and various cycling gear.
>
>The pump itself feels very solid, the in-line pressure guage almost
>seems like it could use a bit of lubricant. It sort of moves in little
>jumps, but once you're near the desired pressure you can just flick it
>with your finger to get a good reading.
>
>I would have stuck with my Zefal HP-X, but I have a frame now that's
>just too long on top for a secure spring mount. I also really don't like
>pumping sideways.
>
>I've only had 2 flats this whole year, and that's with commuting
>everywhere sans car. I'm just too lucky for a real evaluation of the
>*pump*. I'm leaning strongly at switching to CO2 cartridge systems
>should I start having a lot of problems with the pump mount this winter.

Dear Franz,

Sorry to hear of your trouble. It's nice that they sent you free
replacements, but you can buy them online quite easily.

My Topeak mounting clip is fine.

If it ever fails, I'll probably use an ordinary hose clap around a
piece of inner tube. But a couple of heavy zip ties would probably do
quite well.

Cheers,

Carl Fogel

 

[jtaylor]

"Blair P. Houghton" <[email protected]> wrote in message
news:[email protected]...
>
> jtaylor wrote:
> > Can be trouble if there's a cycle attached to the tyre; if so, better to
> > lean it against something.
>
> How hard is it to stand over the top tube while pumping a tire up?
>

Pretty hard if you have a normal press-on pump.

 

[jtaylor]

"dvt" <[email protected]> wrote in message
news:[email protected]...
> Roy Zipris wrote:
> > I don't recall where I heard about this technique, but I have tried it
> > once or twice with no problems: hold the tire with the valve at the
> > top, and simply let the tire dangle freely as you pump. You just need
> > to support everything with one hand at near the valve/pump end. Seemed
> > to work fine.
>
> That's how I recommend doing it. Make sure the wheel is out of the bike,
> as jtaylor noted. And I think it works best if you have the nut on the
> stem. This method seems to reduce my incidence of failed stems compared
> to any other technique I've tried.

It's probably better to lean the cycle against something - that'll keep the
tyre and rim still if you are not perfectly even in applying pressure to
both ends of the pump. Remember that a dangling wheel will have a natural
period similar to pumping frequency, and you could easily hit that with a
few strokes and break the stem despite yourself.

Removing the wheel is only necessary if you are changing the tube or tyre
entirely (unless you have a single-sided wheel mount) , and even then, you
are better off with the wheel in the frame.

 

[Blair P. Houghton]

jtaylor wrote:
> "Blair P. Houghton" <[email protected]> wrote in message
> news:[email protected]...
> >
> > jtaylor wrote:
> > > Can be trouble if there's a cycle attached to the tyre; if so, better to
> > > lean it against something.
> >
> > How hard is it to stand over the top tube while pumping a tire up?
>
> Pretty hard if you have a normal press-on pump.

Huh?

Turn wheel until valve is at top, place pump on valve,
hold wheel, valve, and head of pump in one hand,
operate pump with other hand. Your hand takes all
the lateral stress and the valve gets minimal wiggle.

My floor pump has a hose, but it's been three decades
since I've had a portable pump with a hose. I now carry
both a CO2 injector (first resort) and a micro-pump (last
resort). And a patch kit (first resort) and spare tube
(last resort).

--Blair

 

[jtaylor]

"Blair P. Houghton" <[email protected]> wrote in message
news:[email protected]...
>
> jtaylor wrote:
> > "Blair P. Houghton" <[email protected]> wrote in message
> > news:[email protected]...
> > >
> > > jtaylor wrote:
> > > > Can be trouble if there's a cycle attached to the tyre; if so,
better to
> > > > lean it against something.
> > >
> > > How hard is it to stand over the top tube while pumping a tire up?
> >
> > Pretty hard if you have a normal press-on pump.
>
> Huh?
>
> Turn wheel until valve is at top, place pump on valve,
> hold wheel, valve, and head of pump in one hand,
> operate pump with other hand. Your hand takes all
> the lateral stress and the valve gets minimal wiggle.

While you are straddling the top tube?

And if it is the rear tyre?

Do post a picture...

 

[Blair P. Houghton]

jtaylor wrote:
> "Blair P. Houghton" <[email protected]> wrote in message
> news:[email protected]...
> > Turn wheel until valve is at top, place pump on valve,
> > hold wheel, valve, and head of pump in one hand,
> > operate pump with other hand. Your hand takes all
> > the lateral stress and the valve gets minimal wiggle.
>
> While you are straddling the top tube?

Yes.

> And if it is the rear tyre?

Turn around, straddle the bike, and lean over the
seat instead of the handlebars.

> Do post a picture...

It's not that hard to imagine, really.

--Blair

 

[dvt]

jtaylor wrote:
> It's probably better to lean the cycle against something - that'll keep the
> tyre and rim still if you are not perfectly even in applying pressure to
> both ends of the pump. Remember that a dangling wheel will have a natural
> period similar to pumping frequency, and you could easily hit that with a
> few strokes and break the stem despite yourself.
>
> Removing the wheel is only necessary if you are changing the tube or tyre
> entirely (unless you have a single-sided wheel mount) , and even then, you
> are better off with the wheel in the frame.

Your experience is different than mine. Enough different, in fact, that
I wonder if you've tried letting the wheel dangle. Sure, there's a
resonance, and movement occurs. But there's little force involved, and
tubes stretch quite readily to accommodate that movement. But if you
effectively clamp the wheel, any imbalance in your pumping action has to
be resisted by the stem; this can result in a high force (but little
movement).

I've had better luck pumping with the wheel dangling. This was
reinforced a few weeks ago when I patched a flat on my single speed bike
with a nutted axle. Not wanting to remove the rear wheel for the repair,
I patched it in place. The valve stem broke loose from the tube as I
pumped it up again. Luckily it was a slow leak and I made it home before
I had to replace the tube.

--
Dave
dvt at psu dot edu

Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)

 

[G.T.]

dvt wrote:
> jtaylor wrote:
>
>> It's probably better to lean the cycle against something - that'll
>> keep the
>> tyre and rim still if you are not perfectly even in applying pressure to
>> both ends of the pump. Remember that a dangling wheel will have a
>> natural
>> period similar to pumping frequency, and you could easily hit that with a
>> few strokes and break the stem despite yourself.
>>
>> Removing the wheel is only necessary if you are changing the tube or tyre
>> entirely (unless you have a single-sided wheel mount) , and even then,
>> you
>> are better off with the wheel in the frame.
>
>
> Your experience is different than mine. Enough different, in fact, that
> I wonder if you've tried letting the wheel dangle. Sure, there's a
> resonance, and movement occurs. But there's little force involved, and
> tubes stretch quite readily to accommodate that movement. But if you
> effectively clamp the wheel, any imbalance in your pumping action has to
> be resisted by the stem; this can result in a high force (but little
> movement).
>
> I've had better luck pumping with the wheel dangling. This was
> reinforced a few weeks ago when I patched a flat on my single speed bike
> with a nutted axle. Not wanting to remove the rear wheel for the repair,
> I patched it in place. The valve stem broke loose from the tube as I
> pumped it up again. Luckily it was a slow leak and I made it home before
> I had to replace the tube.
>

Hmmm, in my 26 years of owning presta valved bikes I've pumped the tires
in every way possible and the only time I've had a problem was when I
was in too much of a hurry during a mtn bike race and broke the end of
the valve off. That was with the wheel off of the bike.

Greg

--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons