Sudden flats

[Artoi]

This has happened twice on my already, kind of weird. For no obvious
cause, my rear tyre would flat totally. The first one was two weeks ago
just after leaving the front door (tyre checked). Within 10m, it
suddenly went flat and totally flat. Then this morning, after resting
against the wall overnight, it's again totally flat. No puncture found
again. In b/n time, the same wheel/tyre/tube has been on quite a number
of long rides without problem.

Anyone seen similar? I am totally perplexed as to what the cause may be.
--

 

[Paul Cassel]

Artoi wrote:
> This has happened twice on my already, kind of weird. For no obvious
> cause, my rear tyre would flat totally. The first one was two weeks ago
> just after leaving the front door (tyre checked). Within 10m, it
> suddenly went flat and totally flat. Then this morning, after resting
> against the wall overnight, it's again totally flat. No puncture found
> again. In b/n time, the same wheel/tyre/tube has been on quite a number
> of long rides without problem.
>
> Anyone seen similar? I am totally perplexed as to what the cause may be.
> --
So you can pump it up and it'll hold air with no repairs whatsoever?
That is strange. I'd suspect the tube's valve although the exact
mechanism for your observed behavior escapes me.

-paul

 

[peter]

Paul Cassel wrote:
> Artoi wrote:
> > This has happened twice on my already, kind of weird. For no obvious
> > cause, my rear tyre would flat totally. The first one was two weeks ago
> > just after leaving the front door (tyre checked). Within 10m, it
> > suddenly went flat and totally flat. Then this morning, after resting
> > against the wall overnight, it's again totally flat. No puncture found
> > again. In b/n time, the same wheel/tyre/tube has been on quite a number
> > of long rides without problem.
> >
> > Anyone seen similar? I am totally perplexed as to what the cause may be.
> > --
> So you can pump it up and it'll hold air with no repairs whatsoever?
> That is strange. I'd suspect the tube's valve although the exact
> mechanism for your observed behavior escapes me.

I agree. I've come across a few valves that seemed to be overly
sensitive to getting a bit of dust under the valve seal. Usually
they'd hold air ok, but sometimes they wouldn't seal properly and would
let the tube go flat.

 

[(PeteCresswell)]

Per Artoi:
>Anyone seen similar? I am totally perplexed as to what the cause may be.

Yes.

Replace it with another tube.

Fill up the suspect tube so it's a little larger than it would be inside the
tire, hang it up somewhere, and see what happens over the next days/weeks.

If the new tube goes flat... that tells you something too...
--
PeteCresswell

 

[Artoi]

In article <[email protected]>,
Paul Cassel <[email protected]> wrote:

> Artoi wrote:
> > This has happened twice on my already, kind of weird. For no obvious
> > cause, my rear tyre would flat totally. The first one was two weeks ago
> > just after leaving the front door (tyre checked). Within 10m, it
> > suddenly went flat and totally flat. Then this morning, after resting
> > against the wall overnight, it's again totally flat. No puncture found
> > again. In b/n time, the same wheel/tyre/tube has been on quite a number
> > of long rides without problem.
> >
> > Anyone seen similar? I am totally perplexed as to what the cause may be.
> > --
> So you can pump it up and it'll hold air with no repairs whatsoever?
> That is strange. I'd suspect the tube's valve although the exact
> mechanism for your observed behavior escapes me.

Exactly, very strange.

The first time it happened, I inspected, pumped it up, rode 70-80km over
a number of days and nothing happens before a routine pump up of tyre.
Last night the tyre was tight before I went to bed and this morning it
was totally flat.

Yes, I thought about the valve too as I just couldn't think of any other
place that can release the pressure at that rapid of a rate and that
completely. But the valve looked and functioned ok when I inspected and
worked it.
--

 

[Artoi]

In article <[email protected]>,
"(PeteCresswell)" <[email protected]> wrote:

> Per Artoi:
> >Anyone seen similar? I am totally perplexed as to what the cause may be.

> Replace it with another tube.
>
> Fill up the suspect tube so it's a little larger than it would be inside the
> tire, hang it up somewhere, and see what happens over the next days/weeks.
>
> If the new tube goes flat... that tells you something too...

I haven't gone that far yet as I've been a little lazy. I've pumped it
up again this morning and it seemed to be back to normal again. Just
trying to see if anyone has seen similar. If it happens again, I think
I'll just toss the tube.
--

 

[[email protected]]

peter wrote:
> Paul Cassel wrote:
> > So you can pump it up and it'll hold air with no repairs whatsoever?
> > That is strange. I'd suspect the tube's valve although the exact
> > mechanism for your observed behavior escapes me.
>
> I agree. I've come across a few valves that seemed to be overly
> sensitive to getting a bit of dust under the valve seal. Usually
> they'd hold air ok, but sometimes they wouldn't seal properly and would
> let the tube go flat.

If you have a valve core tool, you could swap it for another valve
core, from a prior flat or with the other wheel or a old / new spare
tube.

 

[Bill Sornson]

Artoi wrote:
> This has happened twice on my already, kind of weird. For no obvious
> cause, my rear tyre would flat totally. The first one was two weeks
> ago just after leaving the front door (tyre checked). Within 10m, it
> suddenly went flat and totally flat. Then this morning, after resting
> against the wall overnight, it's again totally flat. No puncture found
> again. In b/n time, the same wheel/tyre/tube has been on quite a
> number of long rides without problem.
>
> Anyone seen similar? I am totally perplexed as to what the cause may
> be.

I got a flat the other day. Had a brand-new Vittoria spare with a faulty
valve stem/tube interface -- AND my patch kit had melted. After struggling
with it all for a good half hour, a good samaritan rode by and gave me a
tube.

The kicker? I was right in front of my ex-wife's new condo. (Good thing I
don't know what unit!)

The point is that I've had tubes in the past that will hold air fine when
fully inflated, but when unweight-loaded and after losing a little air, it
all leaks out around the valve stem. (Small break in glue I guess --
pressed tight by pressure but opens when reduced?)

Bill "it's always something" S.

 

[Artoi]

In article <[email protected]>,
"Bill Sornson" <[email protected]> wrote:

> Artoi wrote:
> > This has happened twice on my already, kind of weird. For no obvious
> > cause, my rear tyre would flat totally. The first one was two weeks
> > ago just after leaving the front door (tyre checked). Within 10m, it
> > suddenly went flat and totally flat. Then this morning, after resting
> > against the wall overnight, it's again totally flat. No puncture found
> > again. In b/n time, the same wheel/tyre/tube has been on quite a
> > number of long rides without problem.
> >
> > Anyone seen similar? I am totally perplexed as to what the cause may
> > be.
>
> I got a flat the other day. Had a brand-new Vittoria spare with a faulty
> valve stem/tube interface -- AND my patch kit had melted. After struggling
> with it all for a good half hour, a good samaritan rode by and gave me a
> tube.
>
> The kicker? I was right in front of my ex-wife's new condo. (Good thing I
> don't know what unit!)
>
> The point is that I've had tubes in the past that will hold air fine when
> fully inflated, but when unweight-loaded and after losing a little air, it
> all leaks out around the valve stem. (Small break in glue I guess --
> pressed tight by pressure but opens when reduced?)

We have a common thread here. The tube on mine is also a Vittoria.
--

 

[jim beam]

Artoi wrote:
> In article <[email protected]>,
> "Bill Sornson" <[email protected]> wrote:
>
>> Artoi wrote:
>>> This has happened twice on my already, kind of weird. For no obvious
>>> cause, my rear tyre would flat totally. The first one was two weeks
>>> ago just after leaving the front door (tyre checked). Within 10m, it
>>> suddenly went flat and totally flat. Then this morning, after resting
>>> against the wall overnight, it's again totally flat. No puncture found
>>> again. In b/n time, the same wheel/tyre/tube has been on quite a
>>> number of long rides without problem.
>>>
>>> Anyone seen similar? I am totally perplexed as to what the cause may
>>> be.
>> I got a flat the other day. Had a brand-new Vittoria spare with a faulty
>> valve stem/tube interface -- AND my patch kit had melted. After struggling
>> with it all for a good half hour, a good samaritan rode by and gave me a
>> tube.
>>
>> The kicker? I was right in front of my ex-wife's new condo. (Good thing I
>> don't know what unit!)
>>
>> The point is that I've had tubes in the past that will hold air fine when
>> fully inflated, but when unweight-loaded and after losing a little air, it
>> all leaks out around the valve stem. (Small break in glue I guess --
>> pressed tight by pressure but opens when reduced?)
>
> We have a common thread here. The tube on mine is also a Vittoria.
> --
indeed. i had a spate of these with vittoria a while back too. they
burst at the fold where the tubes are put on a rack after molding. i've
always used michelin since and i've never had that kind of flat again.

 

[Bill Sornson]

jim beam wrote:
> Artoi wrote:
>> In article <[email protected]>,
>> "Bill Sornson" <[email protected]> wrote:
>>
>>> Artoi wrote:
>>>> This has happened twice on my already, kind of weird. For no
>>>> obvious cause, my rear tyre would flat totally. The first one was
>>>> two weeks ago just after leaving the front door (tyre checked).
>>>> Within 10m, it suddenly went flat and totally flat. Then this
>>>> morning, after resting against the wall overnight, it's again
>>>> totally flat. No puncture found again. In b/n time, the same
>>>> wheel/tyre/tube has been on quite a number of long rides without
>>>> problem. Anyone seen similar? I am totally perplexed as to what the
>>>> cause
>>>> may be.
>>> I got a flat the other day. Had a brand-new Vittoria spare with a
>>> faulty valve stem/tube interface -- AND my patch kit had melted. After
>>> struggling with it all for a good half hour, a good samaritan
>>> rode by and gave me a tube.
>>>
>>> The kicker? I was right in front of my ex-wife's new condo. (Good
>>> thing I don't know what unit!)
>>>
>>> The point is that I've had tubes in the past that will hold air
>>> fine when fully inflated, but when unweight-loaded and after losing
>>> a little air, it all leaks out around the valve stem. (Small break
>>> in glue I guess -- pressed tight by pressure but opens when
>>> reduced?)
>>
>> We have a common thread here. The tube on mine is also a Vittoria.
>> --
> indeed. i had a spate of these with vittoria a while back too. they
> burst at the fold where the tubes are put on a rack after molding. i've
> always used michelin since and i've never had that kind of flat
> again.

Hmm. Well in general my tubes with this sort of problem (a leak at the
valve "sleeve" from not being glued properly) haven't /burst/ at all;
they've just gone flat (or not held air at all).

 

[Artoi]

In article <[email protected]>,
jim beam <[email protected]> wrote:

> Artoi wrote:
> > In article <[email protected]>,
> > "Bill Sornson" <[email protected]> wrote:
> >
> >> Artoi wrote:
> >>> This has happened twice on my already, kind of weird. For no obvious
> >>> cause, my rear tyre would flat totally. The first one was two weeks
> >>> ago just after leaving the front door (tyre checked). Within 10m, it
> >>> suddenly went flat and totally flat. Then this morning, after resting
> >>> against the wall overnight, it's again totally flat. No puncture found
> >>> again. In b/n time, the same wheel/tyre/tube has been on quite a
> >>> number of long rides without problem.
> >>>
> >>> Anyone seen similar? I am totally perplexed as to what the cause may
> >>> be.
> >> I got a flat the other day. Had a brand-new Vittoria spare with a faulty
> >> valve stem/tube interface -- AND my patch kit had melted. After
> >> struggling
> >> with it all for a good half hour, a good samaritan rode by and gave me a
> >> tube.
> >>
> >> The kicker? I was right in front of my ex-wife's new condo. (Good thing
> >> I
> >> don't know what unit!)
> >>
> >> The point is that I've had tubes in the past that will hold air fine when
> >> fully inflated, but when unweight-loaded and after losing a little air, it
> >> all leaks out around the valve stem. (Small break in glue I guess --
> >> pressed tight by pressure but opens when reduced?)
> >
> > We have a common thread here. The tube on mine is also a Vittoria.
> > --
> indeed. i had a spate of these with vittoria a while back too. they
> burst at the fold where the tubes are put on a rack after molding. i've
> always used michelin since and i've never had that kind of flat again.

But I don't think we are talking about a burst tube, rather some issue
with the valve.
--

 

[Earl Bollinger]

"Artoi" <[email protected]> wrote in message
news:[email protected]...
> This has happened twice on my already, kind of weird. For no obvious
> cause, my rear tyre would flat totally. The first one was two weeks ago
> just after leaving the front door (tyre checked). Within 10m, it
> suddenly went flat and totally flat. Then this morning, after resting
> against the wall overnight, it's again totally flat. No puncture found
> again. In b/n time, the same wheel/tyre/tube has been on quite a number
> of long rides without problem.
>
> Anyone seen similar? I am totally perplexed as to what the cause may be.
> --

I have seen this problem happen a number of times with Presta valves.
Leave the little plastic dust cap off the valve.
Don't bother screwing the little lock nut back in either.
If the valve gets a tiny bit of crud inside it may not seat all the way, and
when you put on the dust cap, it starts to leak.
I quit bothering with the tiny lock nut too, leave it out, I had the small
threaded valve shaft break off.
I also have had the little nut screw off the end without turning the
threaded shaft thus opening the valve. Now you are stuck as you can't put
air in.
Is the valve end bent? Sometimes this causes the valve to leak too.
Of course like others mentioned tubes do go bad. I had one tube that would
leak out after ten hours or so. I had to inflate the tube like a balloon to
find the super slow leak. I was a lot of luck as even pumped up like a
balloon I almost missed the slow leak. But as luck would have it the tiny
hole was on a seam, and I was unable to get it to patch good.

 

[catzz66]

Artoi wrote:
> This has happened twice on my already, kind of weird. For no obvious
> cause, my rear tyre would flat totally. The first one was two weeks ago
> just after leaving the front door (tyre checked). Within 10m, it
> suddenly went flat and totally flat. Then this morning, after resting
> against the wall overnight, it's again totally flat. No puncture found
> again. In b/n time, the same wheel/tyre/tube has been on quite a number
> of long rides without problem.
>
> Anyone seen similar? I am totally perplexed as to what the cause may be.
> --

My last mystery flat was just a well placed thorn. I didn't examine my
tire well enough, thinking the kevlar belt would not let anything like
that through. I pay a lot closer attention to my tires now and don't
take the kevlar belt for granted.

 

[[email protected]]

Earl Bollinger writes:

>> This has happened twice on my already, kind of weird. For no
>> obvious cause, my rear tyre would flat totally. The first one was
>> two weeks ago just after leaving the front door (tyre checked).
>> Within 10m, it suddenly went flat and totally flat. Then this
>> morning, after resting against the wall overnight, it's again
>> totally flat. No puncture found again. In b/n time, the same
>> wheel/tyre/tube has been on quite a number of long rides without
>> problem.

>> Anyone seen similar? I am totally perplexed as to what the cause
may be.

> I have seen this problem happen a number of times with Presta
> valves. Leave the little plastic dust cap off the valve. Don't
> bother screwing the little lock nut back in either.

This all sounds so much like the knurled lock nut causing valve stem
separation from the tube, which is what this might be. There was a
manufacturing period where stem attachment was incorrectly done.
Masochists decided it was their own fault because they used the stem
jam nut.

As I pointed out, you can tighten the jam nut manually as tight as you
can before inflation to 100psi and note that the nut is loose after
inflation. That is how great the force of inflation is compared to
finger tightening the nut that is there for the purpose of using a
frame fit pump.

> If the valve gets a tiny bit of crud inside it may not seat all the
> way, and when you put on the dust cap, it starts to leak. I quit
> bothering with the tiny lock nut too, leave it out, I had the small
> threaded valve shaft break off.

Stems break because the pump force was aimed at the stem instead of
the fist of the hand holding the pump on the valve stem. Don't hold
the tire, hold the pump head.

> I also have had the little nut screw off the end without turning the
> threaded shaft thus opening the valve. Now you are stuck as you
> can't put air in.

> Is the valve end bent? Sometimes this causes the valve to leak too.
> Of course like others mentioned tubes do go bad.

How so?

> I had one tube that would leak out after ten hours or so. I had to
> inflate the tube like a balloon to find the super slow leak. I was
> a lot of luck as even pumped up like a balloon I almost missed the
> slow leak. But as luck would have it the tiny hole was on a seam,
> and I was unable to get it to patch good.

Use a BIC shaver head (break off the handle so it will fit in the
patch kit) and shave off the raised seam. You can't get rid of the
seam with sand paper.

Jobst Brandt

 

[Artoi]

In article <[email protected]>,
"Earl Bollinger" <[email protected]> wrote:

> "Artoi" <[email protected]> wrote in message
> news:[email protected]...
> > This has happened twice on my already, kind of weird. For no obvious
> > cause, my rear tyre would flat totally. The first one was two weeks ago
> > just after leaving the front door (tyre checked). Within 10m, it
> > suddenly went flat and totally flat. Then this morning, after resting
> > against the wall overnight, it's again totally flat. No puncture found
> > again. In b/n time, the same wheel/tyre/tube has been on quite a number
> > of long rides without problem.
> >
> > Anyone seen similar? I am totally perplexed as to what the cause may be.
> > --
>
> I have seen this problem happen a number of times with Presta valves.
> Leave the little plastic dust cap off the valve.

Why? Does this interfere with something? Doesn't the dust cap prevent
the accumulation of crud referred to below?

> Don't bother screwing the little lock nut back in either.

Why? I thought the lock nut made sure the valve is seated tightly.

> If the valve gets a tiny bit of crud inside it may not seat all the way, and
> when you put on the dust cap, it starts to leak.
> I quit bothering with the tiny lock nut too, leave it out, I had the small
> threaded valve shaft break off.
> I also have had the little nut screw off the end without turning the
> threaded shaft thus opening the valve. Now you are stuck as you can't put
> air in.
> Is the valve end bent? Sometimes this causes the valve to leak too.

Not that I can see. But the valve on the one of my other wheel is indeed
bent slightly. No problems there so far and fingers crossed.

> Of course like others mentioned tubes do go bad. I had one tube that would
> leak out after ten hours or so. I had to inflate the tube like a balloon to
> find the super slow leak. I was a lot of luck as even pumped up like a
> balloon I almost missed the slow leak. But as luck would have it the tiny
> hole was on a seam, and I was unable to get it to patch good.

Thanks all who has added suggestions and ideas. I've given up on being
inquisitive after the wheel going flat again overnight. Spent 20mins and
swapped in a new tube. Will blow the problem tube up and let it hang
there and see what happens.
--

 

[Dan O]

[email protected] wrote:
> Earl Bollinger writes:
>
> >> This has happened twice on my already, kind of weird. For no
> >> obvious cause, my rear tyre would flat totally. The first one was
> >> two weeks ago just after leaving the front door (tyre checked).
> >> Within 10m, it suddenly went flat and totally flat. Then this
> >> morning, after resting against the wall overnight, it's again
> >> totally flat. No puncture found again. In b/n time, the same
> >> wheel/tyre/tube has been on quite a number of long rides without
> >> problem.
>
> >> Anyone seen similar? I am totally perplexed as to what the cause
> may be.
>
> > I have seen this problem happen a number of times with Presta
> > valves. Leave the little plastic dust cap off the valve. Don't
> > bother screwing the little lock nut back in either.
>
> This all sounds so much like the knurled lock nut causing valve stem
> separation from the tube, which is what this might be. There was a
> manufacturing period where stem attachment was incorrectly done.
> Masochists decided it was their own fault because they used the stem
> jam nut.
>
> As I pointed out, you can tighten the jam nut manually as tight as you
> can before inflation to 100psi and note that the nut is loose after
> inflation. That is how great the force of inflation is compared to
> finger tightening the nut that is there for the purpose of using a
> frame fit pump.
>

I pumped up my rear tire one morning (using floor pump), then, while
screwing down the lock nut, heard a "ssssSSSSSS..." Quickly backed off
the lock nut and it stopped leaking. Screwed it down a bit again just
to verify: "sssssssss..." Backed it off, pumped tire and rode in to
work.

Later I noticed the rear tire going low. Rode to LBS, had new tube
installed, and okay now.


> > If the valve gets a tiny bit of crud inside it may not seat all the
> > way, and when you put on the dust cap, it starts to leak. I quit
> > bothering with the tiny lock nut too, leave it out, I had the small
> > threaded valve shaft break off.
>
> Stems break because the pump force was aimed at the stem instead of
> the fist of the hand holding the pump on the valve stem. Don't hold
> the tire, hold the pump head.
>

I recently got a Topeak Morph pump (mini folding floor pump). I like
it.

 

[[email protected]]

Dan Overman writes:

>>>> This has happened twice on my already, kind of weird. For no
>>>> obvious cause, my rear tyre would flat totally. The first one
>>>> was two weeks ago just after leaving the front door (tyre
>>>> checked). Within 10m, it suddenly went flat and totally flat.
>>>> Then this morning, after resting against the wall overnight, it's
>>>> again totally flat. No puncture found again. In b/n time, the
>>>> same wheel/tyre/tube has been on quite a number of long rides
>>>> without problem.

>>>> Anyone seen similar? I am totally perplexed as to what the cause
>>>> may be.

>>> I have seen this problem happen a number of times with Presta
>>> valves. Leave the little plastic dust cap off the valve. Don't
>>> bother screwing the little lock nut back in either.

>> This all sounds so much like the knurled lock nut causing valve
>> stem separation from the tube, which is what this might be. There
>> was a manufacturing period where stem attachment was incorrectly
>> done. Masochists decided it was their own fault because they used
>> the stem jam nut.

>> As I pointed out, you can tighten the jam nut manually as tight as
>> you can before inflation to 100psi and note that the nut is loose
>> after inflation. That is how great the force of inflation is
>> compared to finger tightening the nut that is there for the purpose
>> of using a frame fit pump.

> I pumped up my rear tire one morning (using floor pump), then, while
> screwing down the lock nut, heard a "ssssSSSSSS..." Quickly backed
> off the lock nut and it stopped leaking. Screwed it down a bit
> again just to verify: "sssssssss..." Backed it off, pumped tire and
> rode in to work.

> Later I noticed the rear tire going low. Rode to LBS, had new tube
> installed, and OK now.

That is a classic case of stem separation, and it didn't occur from
screwing the knurled jam nut down against the rim. That only exposed
that the separation had occurred. The same effect is detectable when
attaching a frame fit pump to the stem.

>>> If the valve gets a tiny bit of crud inside it may not seat all
>>> the way, and when you put on the dust cap, it starts to leak. I
>>> quit bothering with the tiny lock nut too, leave it out, I had the
>>> small threaded valve shaft break off.

>> Stems break because the pump force was aimed at the stem instead of
>> the fist of the hand holding the pump on the valve stem. Don't
>> hold the tire, hold the pump head.

> I recently got a Topeak Morph pump (mini folding floor pump). I
> like it.

I don't volunteer to use my frame fit pump at home where I have a
double acting floor pump.

Jobst Brandt

 

[Earl Bollinger]

<[email protected]> wrote in message
news:[email protected]...
> Earl Bollinger writes:
>
>>> This has happened twice on my already, kind of weird. For no
>>> obvious cause, my rear tyre would flat totally. The first one was
>>> two weeks ago just after leaving the front door (tyre checked).
>>> Within 10m, it suddenly went flat and totally flat. Then this
>>> morning, after resting against the wall overnight, it's again
>>> totally flat. No puncture found again. In b/n time, the same
>>> wheel/tyre/tube has been on quite a number of long rides without
>>> problem.
>
>>> Anyone seen similar? I am totally perplexed as to what the cause
> may be.
>
>> I have seen this problem happen a number of times with Presta
>> valves. Leave the little plastic dust cap off the valve. Don't
>> bother screwing the little lock nut back in either.
>
> This all sounds so much like the knurled lock nut causing valve stem
> separation from the tube, which is what this might be. There was a
> manufacturing period where stem attachment was incorrectly done.
> Masochists decided it was their own fault because they used the stem
> jam nut.
>
> As I pointed out, you can tighten the jam nut manually as tight as you
> can before inflation to 100psi and note that the nut is loose after
> inflation. That is how great the force of inflation is compared to
> finger tightening the nut that is there for the purpose of using a
> frame fit pump.
>
>> If the valve gets a tiny bit of crud inside it may not seat all the
>> way, and when you put on the dust cap, it starts to leak. I quit
>> bothering with the tiny lock nut too, leave it out, I had the small
>> threaded valve shaft break off.
>
> Stems break because the pump force was aimed at the stem instead of
> the fist of the hand holding the pump on the valve stem. Don't hold
> the tire, hold the pump head.
>
>> I also have had the little nut screw off the end without turning the
>> threaded shaft thus opening the valve. Now you are stuck as you
>> can't put air in.
>
>> Is the valve end bent? Sometimes this causes the valve to leak too.
>> Of course like others mentioned tubes do go bad.
>
> How so?
>
>> I had one tube that would leak out after ten hours or so. I had to
>> inflate the tube like a balloon to find the super slow leak. I was
>> a lot of luck as even pumped up like a balloon I almost missed the
>> slow leak. But as luck would have it the tiny hole was on a seam,
>> and I was unable to get it to patch good.
>
> Use a BIC shaver head (break off the handle so it will fit in the
> patch kit) and shave off the raised seam. You can't get rid of the
> seam with sand paper.
>
> Jobst Brandt

My apologies, I was talking about the top of the valve, there is a little
tiny threaded shaft with a oblong shaped thingie that i call a lock nut.
The idea was to unscrew this to unlock the presta valve, and after pumping
up the tire to screw it back down to lock the valve. if this little tiny
lock nut thingie is not screwed down just right, and you then put on a
plastic dust cap over it all, there could be enough bressure from the dusct
cap to unseat the valve a little bit causing it to leak.
But you are right about the larger threaded locknut on the valve though, I
only use it to help get the tire pumped up to start after changing out a
tire or tube or something.

 

[Werehatrack]

On Mon, 18 Dec 2006 01:17:38 GMT, Artoi <[email protected]> may have
said:

>This has happened twice on my already, kind of weird. For no obvious
>cause, my rear tyre would flat totally. The first one was two weeks ago
>just after leaving the front door (tyre checked). Within 10m, it
>suddenly went flat and totally flat. Then this morning, after resting
>against the wall overnight, it's again totally flat. No puncture found
>again. In b/n time, the same wheel/tyre/tube has been on quite a number
>of long rides without problem.
>
>Anyone seen similar? I am totally perplexed as to what the cause may be.

Inflate it, dash a little dishwashing detergent on the base of the
valve stem, and then and wiggle the stem a bit. I suspect that you've
got a stem flange failure; if so, the base will form bubbles when the
stem is moved. That type of fault often results in the behavior that
you are seeing, and it's essentially unrepairable; if it is what has
happened, just replace the tube.

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