Why Nutrak Schraeder Valves Leaking?

I bought two new Nutrak Schraeder-valved inner tubes from
my LBS. Within a week, without use, one went flat and the
other is very soft.
I removed the inner tube and put it under water. No
punctures but a bubble of air was released from the valve
centre every 30 seconds. The LBS replaced it but the
replacement is worse - it leaks a bubble every 5 seconds.

Are Nutrack a good make? and what could be the problem?

DAvy

On Feb 27, 5:46 am, Davy wrote:
I bought two new Nutrak Schraeder-valved inner tubes from
my LBS. Within a week, without use, one went flat and the
other is very soft.
I removed the inner tube and put it under water. No
punctures but a bubble of air was released from the valve
centre every 30 seconds. The LBS replaced it but the
replacement is worse - it leaks a bubble every 5 seconds.

Are Nutrack a good make? and what could be the problem?


A 4-way tire valve tool and some fresh valves costs under $5 at any
auto parts store. Snug up the valves. If they still leak, throw some
fresh ones in there. An essential toolkit doodad for anyone smart
enough to run utlitarian Schraders.

"Davy" wrote:
(clip) I removed the inner tube and put it under water. No
punctures but a bubble of air was released from the valve
centre every 30 seconds. The LBS replaced it but the
replacement is worse - it leaks a bubble every 5 seconds. (clip)
^^^^^^^^^^^^^^^^^^^^
A little spit on your finger tip would have shown you the problem without
even removing the wheel from the bike. A new valve core is an obvious fix.
I'm surprised the LBS didn't do that, rather than replacing the tube.
Furthermore, a valve cap would fix it, and also keep dirt out of the valve
stem. Dirt in the stem gets blown in when you add air, which can cause
leakage. My understanding is that the main purpose of the valve core is to
hold air while you screw on the valve cap.

Leo Lichtman wrote:

My understanding is that the main purpose of the valve core is to
hold air while you screw on the valve cap.

If that were the case, then valve caps would be strong, with effective
gaskets. All the valve caps I've seen on bicycle tubes lately are
just for keeping filth off the valve, nothing more. Their threads
strip before they are tight enough to seal anything.

Chalo

On Fri, 27 Feb 2009 10:58:19 -0800, "Leo Lichtman"
wrote:


"Davy" wrote:
(clip) I removed the inner tube and put it under water. No
punctures but a bubble of air was released from the valve
centre every 30 seconds. The LBS replaced it but the
replacement is worse - it leaks a bubble every 5 seconds. (clip)
^^^^^^^^^^^^^^^^^^^^
A little spit on your finger tip would have shown you the problem without
even removing the wheel from the bike. A new valve core is an obvious fix.
I'm surprised the LBS didn't do that, rather than replacing the tube.
Furthermore, a valve cap would fix it, and also keep dirt out of the valve
stem. Dirt in the stem gets blown in when you add air, which can cause
leakage. My understanding is that the main purpose of the valve core is to
hold air while you screw on the valve cap.

Dear Leo,

A normal Schrader valve is as air-tight as a normal presta valve.

Lots of cars are missing dust caps on their Schrader valves.

Schrader valve caps can range from plastic, which won't hold air, to
metal caps with O-rings, which will.

Whatever the details of the repair attempts may be, the original
poster's leaky Schrader valve is due to . . .

A) two bad valve cores
B) two inner tubes with bad valve stems
C) someone who can't screw cores into stems
D) all of the above

Cheers,

Carl Fogel

Leo Lichtman wrote:
My understanding is that the main purpose of the valve core is to
hold air while you screw on the valve cap.

Your understanding is incorrect.

Chalo wrote:
Leo Lichtman wrote:
My understanding is that the main purpose of the valve core is to
hold air while you screw on the valve cap.

If that were the case, then valve caps would be strong, with effective
gaskets. All the valve caps I've seen on bicycle tubes lately are
just for keeping filth off the valve, nothing more. Their threads
strip before they are tight enough to seal anything.

Chalo

Same is true for automotive apps, but if you frequent hot rod type shops
you can actually buy chromed brass valve stem caps with little gaskets
in them. (you can also buy ones in the shape of skulls, dice, little
F*rd logos, etc...)

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Still Just Me wrote:
On Fri, 27 Feb 2009 12:20:57 -0700, wrote:

Dear Leo,

A normal Schrader valve is as air-tight as a normal presta valve.

Tighter, I would think. Shraders usually have a rubber to seat gasket
whereas Presta's are metal to metal AFAIR.

Lots of cars are missing dust caps on their Schrader valves.

Which eventually leads to valve problems.

Schrader valve caps can range from plastic, which won't hold air, to
metal caps with O-rings, which will.

Whatever the details of the repair attempts may be, the original
poster's leaky Schrader valve is due to . . .

A) two bad valve cores
B) two inner tubes with bad valve stems
C) someone who can't screw cores into stems
D) all of the above

Agreed.

Presta cores seal with a similar material and diameter to Schrader:
http://www.yellowjersey.org/PV_SECT.JPG

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Fri, 27 Feb 2009 15:30:35 -0500, Still Just Me
wrote:

On Fri, 27 Feb 2009 12:20:57 -0700, wrote:

Dear Leo,

A normal Schrader valve is as air-tight as a normal presta valve.

Tighter, I would think. Shraders usually have a rubber to seat gasket
whereas Presta's are metal to metal AFAIR.

Lots of cars are missing dust caps on their Schrader valves.

Which eventually leads to valve problems.

Schrader valve caps can range from plastic, which won't hold air, to
metal caps with O-rings, which will.

Whatever the details of the repair attempts may be, the original
poster's leaky Schrader valve is due to . . .

A) two bad valve cores
B) two inner tubes with bad valve stems
C) someone who can't screw cores into stems
D) all of the above

Agreed.

Dear Still,

Schrader (on right) and presta (on left) both use black rubber seals:
http://i40.tinypic.com/30jsgsx.jpg

The Schrader's actual sealing ring isn't the black and obvious one.
It's a smaller seal, often red, a long ways from the dust cap and too
hard for me to get a good photo:
http://i44.tinypic.com/6z0eqg.jpg

Problems with Schrader valves, with or without dust caps, are
extremely rare on roads.

Cheers,

Carl Fogel

On 27 Feb, 11:46, Davy wrote:
I bought two new Nutrak Schraeder-valved inner tubes from
my LBS. *Within a week, without use, one went flat and the
other is very soft.
I removed the inner tube and put it under water. *No
punctures but a bubble of air was released from the valve
centre every 30 seconds. *The LBS replaced it but the
replacement is worse - it leaks a bubble every 5 seconds.

Are Nutrack a good make? and what could be the problem?

DAvy

it needs a cap
TJ