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Mountain bike punctures - valve being torn off.



 
 
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  #1  
Old September 14th 09, 08:18 AM posted to uk.rec.cycling
Doki
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Posts: 460
Default Mountain bike punctures - valve being torn off.

I keep getting punctures on my mountain bike, where the Schraeder valve has
been pulled off the tube. Clearly, the tyre is rotating slightly on the rim
under braking, and pulling the tube along with it, which eventually rips the
valve off.

Tyres are 2.25" Panaracers, running at a fairly low pressure, and are well
within the maximum specs for the rim (I think the max is 2.5"). I don't want
to increase pressure, unless I really have to.

Any ideas on possible remedies? I don't really want to superglue the tyres
to the rim... The tyres are also about 4 years old, if that makes any odds.

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  #2  
Old September 14th 09, 09:08 AM posted to uk.rec.cycling
Just zis Guy, you know?[_2_]
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Posts: 4,166
Default Mountain bike punctures - valve being torn off.

On Sep 14, 8:18*am, "Doki" wrote:
I keep getting punctures on my mountain bike, where the Schraeder valve has
been pulled off the tube. Clearly, the tyre is rotating slightly on the rim
under braking, and pulling the tube along with it, which eventually rips the
valve off.

Tyres are 2.25" Panaracers, running at a fairly low pressure, and are well
within the maximum specs for the rim (I think the max is 2.5"). I don't want
to increase pressure, unless I really have to.

Any ideas on possible remedies? I don't really want to superglue the tyres
to the rim... The tyres are also about 4 years old, if that makes any odds.


Do the valves have threaded stems with retainers on them or are they
just pushed in?
  #3  
Old September 14th 09, 09:12 AM posted to uk.rec.cycling
Doki
external usenet poster
 
Posts: 460
Default Mountain bike punctures - valve being torn off.

Just zis Guy, you know? wrote:
On Sep 14, 8:18 am, "Doki" wrote:
I keep getting punctures on my mountain bike, where the Schraeder
valve has been pulled off the tube. Clearly, the tyre is rotating
slightly on the rim under braking, and pulling the tube along with
it, which eventually rips the valve off.

Tyres are 2.25" Panaracers, running at a fairly low pressure, and
are well within the maximum specs for the rim (I think the max is
2.5"). I don't want to increase pressure, unless I really have to.

Any ideas on possible remedies? I don't really want to superglue the
tyres to the rim... The tyres are also about 4 years old, if that
makes any odds.


Do the valves have threaded stems with retainers on them or are they
just pushed in?


I've had both kinds, and done it to both.
  #4  
Old September 14th 09, 09:24 AM posted to uk.rec.cycling
Peter Clinch
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Posts: 4,852
Default Mountain bike punctures - valve being torn off.


Any ideas on possible remedies? I don't really want to superglue the tyres
to the rim... The tyres are also about 4 years old, if that makes any odds.


I can only think that the cause of the problem is the tyre moving around
the rim and taking the inner with them. If it's a recent thing I'd
change your tyres, maybe they're getting knackered around the bead?

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/
  #5  
Old September 14th 09, 09:33 AM posted to uk.rec.cycling
pk
external usenet poster
 
Posts: 366
Default Mountain bike punctures - valve being torn off.

"Doki" wrote in message
...
I keep getting punctures on my mountain bike, where the Schraeder valve has
been pulled off the tube. Clearly, the tyre is rotating slightly on the
rim
under braking, and pulling the tube along with it, which eventually rips
the
valve off.

Tyres are 2.25" Panaracers, running at a fairly low pressure, and are well
within the maximum specs for the rim (I think the max is 2.5"). I don't
want
to increase pressure, unless I really have to.

Any ideas on possible remedies? I don't really want to superglue the tyres
to the rim... The tyres are also about 4 years old, if that makes any
odds.



The low pressure is your problem, allowing the tyre to rotate. the solution
is to increase the pressure!!

pk

  #6  
Old September 14th 09, 09:50 AM posted to uk.rec.cycling
Ace[_3_]
external usenet poster
 
Posts: 453
Default Mountain bike punctures - valve being torn off.

On Mon, 14 Sep 2009 08:18:07 +0100, "Doki" wrote:

I keep getting punctures on my mountain bike, where the Schraeder valve has
been pulled off the tube. Clearly, the tyre is rotating slightly on the rim
under braking, and pulling the tube along with it, which eventually rips the
valve off.

Tyres are 2.25" Panaracers, running at a fairly low pressure, and are well
within the maximum specs for the rim (I think the max is 2.5"). I don't want
to increase pressure, unless I really have to.

Any ideas on possible remedies? I don't really want to superglue the tyres
to the rim... The tyres are also about 4 years old, if that makes any odds.


Haven't seen these for years, and TBH I'm not even certain they were
ever made for pedal cycles, but some trials motorbikes, running very
low pressures in tubed tyres, would have a retaining device bolted
through the rim. This would be a shaped flat plate, sized to fit
between the beads of the tyre, but within the rim, and would be
securely tightened from the outside.

Not the best description, so I'll try some ASCII art instead.

| | ---- Tyre
| plate |
\ | /
\ \ V / / ---- Rim
\ \============= / /
\ \ || / /
\______||______/
[||]

Not sure that helps, nor where you would find such a thing, but
hopefully you'll get the idea.

  #7  
Old September 14th 09, 09:54 AM posted to uk.rec.cycling
Wm...
external usenet poster
 
Posts: 1,327
Default Mountain bike punctures - valve being torn off.

Mon, 14 Sep 2009 09:33:52
uk.rec.cycling pk

"Doki" wrote in message
...
I keep getting punctures on my mountain bike, where the Schraeder valve has
been pulled off the tube. Clearly, the tyre is rotating slightly on
the rim
under braking, and pulling the tube along with it, which eventually
rips the
valve off.

Tyres are 2.25" Panaracers, running at a fairly low pressure, and are well
within the maximum specs for the rim (I think the max is 2.5"). I
don't want
to increase pressure, unless I really have to.

Any ideas on possible remedies? I don't really want to superglue the tyres
to the rim... The tyres are also about 4 years old, if that makes any
odds.



The low pressure is your problem, allowing the tyre to rotate. the
solution is to increase the pressure!!



That is what I think too.

--
Wm...
Reply-To: address valid for at least 7 days
  #8  
Old September 14th 09, 10:48 AM posted to uk.rec.cycling
Doki
external usenet poster
 
Posts: 460
Default Mountain bike punctures - valve being torn off.


"Ace" wrote in message
...
On Mon, 14 Sep 2009 08:18:07 +0100, "Doki" wrote:

I keep getting punctures on my mountain bike, where the Schraeder valve
has
been pulled off the tube. Clearly, the tyre is rotating slightly on the
rim
under braking, and pulling the tube along with it, which eventually rips
the
valve off.

Tyres are 2.25" Panaracers, running at a fairly low pressure, and are well
within the maximum specs for the rim (I think the max is 2.5"). I don't
want
to increase pressure, unless I really have to.

Any ideas on possible remedies? I don't really want to superglue the tyres
to the rim... The tyres are also about 4 years old, if that makes any
odds.


Haven't seen these for years, and TBH I'm not even certain they were
ever made for pedal cycles, but some trials motorbikes, running very
low pressures in tubed tyres, would have a retaining device bolted
through the rim. This would be a shaped flat plate, sized to fit
between the beads of the tyre, but within the rim, and would be
securely tightened from the outside.

Not the best description, so I'll try some ASCII art instead.

| | ---- Tyre
| plate |
\ | /
\ \ V / / ---- Rim
\ \============= / /
\ \ || / /
\______||______/
[||]

Not sure that helps, nor where you would find such a thing, but
hopefully you'll get the idea.


Yep, I know what you mean. Never heard of them being available for pushbikes
though - I suspect most racers use higher pressures and ride full
suspension, or go tubeless, so there's no real market for something like
that (extra weight).

  #9  
Old September 14th 09, 11:07 AM posted to uk.rec.cycling
Keitht
external usenet poster
 
Posts: 1,631
Default Mountain bike punctures - valve being torn off.

Doki wrote:
I keep getting punctures on my mountain bike, where the Schraeder valve has
been pulled off the tube. Clearly, the tyre is rotating slightly on the rim
under braking, and pulling the tube along with it, which eventually rips
the
valve off.

Tyres are 2.25" Panaracers, running at a fairly low pressure, and are well
within the maximum specs for the rim (I think the max is 2.5"). I don't
want
to increase pressure, unless I really have to.

Any ideas on possible remedies? I don't really want to superglue the tyres
to the rim... The tyres are also about 4 years old, if that makes any odds.

Have you got enough pressure in them?
Tubes move about at low pressure.
How about the recommended max/min?

Failing that, different rim tape or glue the buggers in.
--

Come to Dave & Boris - your cycle security experts.
  #10  
Old September 14th 09, 11:34 AM posted to uk.rec.cycling
Wm...
external usenet poster
 
Posts: 1,327
Default Mountain bike punctures - valve being torn off.

Mon, 14 Sep 2009 10:48:34
uk.rec.cycling Doki


Yep, I know what you mean. Never heard of them being available for
pushbikes though - I suspect most racers use higher pressures and ride
full suspension, or go tubeless, so there's no real market for
something like that (extra weight).


Just curious, why don't you want to increase the pressure if that would
solve the problem?

--
Wm...
Reply-To: address valid for at least 7 days
 




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