Mavic Ksyriums rims and tube failures at valve base

On Aug 24, 10:18*pm, Jobst Brandt wrote:
a shy person sniped:





I've got Mavic Ksyrium SL Premium wheels and my tubes keep
developing a slow leak at the base of the valve stem. *My dealer
suggested using a short piece of rim tape over the valve stem hole
to provide a bit of cushioning and it helped... a little... I got
700 miles before the tubes started to leak instead of only 300
miles without the cushioning. The Mavic web site doesn't seem to
provide any way to ask for technical support so I'm stuck. *Anyone
else ever had this problem, any ideas for a more permanent fix?
One day last week I rode my bicycle and had a great ride. *I came
home and hung the bike by its crossbar on the rack where it lives
when not in use. *The next day i went to ride it and found that the
rear tire was completely deflated. *Investigation showed that there
was a small hole on the base of the reinforced section where the
valve is. *This was an IRC tube and it was on a Ambrosio Evolution
TQB rim. *The tube was the proper size for the tire and no valve nut
was on the tube or used during inflation. *The tire had been
inflated with a floor pump and there had not been any side pressure
exerted on the valve stem during pumping. *There are not any burrs
or sharp edges on the edge of the valve hole in the rim. *It seems
that this is one of those things that just happen from time to time.

Stop making pseudo excuses for rumored mistreatment of inner tubes.
Valve stem nuts and rim valve ports do not cause these leaks. *Leaks
at the valve stem were tube manufacturing flaws that most people
experienced once upon a time and now no longer do because the process
has been corrected. *That so many brands had these flaws at the same
time indicates that they all bought their branded tubes from the same
manufacturer... so much for most brand names.

I am amazed how quick bicyclists were to accept blame for valve stem
related leaks... pounding chest, confessing to misuse and wearing sack
cloth with ashes! *Mea culpa, mea culpa, mea culpa!

Cut it out! *Those of us who have been pumping tires with Silca Impero
frame pumps by hand for ages without leaks know why tube stems have
knurled retention nuts. *They are knurled because they are intended to
be fastened with thumb and forefinger, rather than wrenching tight.
They keep the stem from submerging when a Campagnolo pump head
(without a lever or hose) is used.

As I mentioned, the nut can be tightened as tight as a hand can make
it before inflating to 100 PSI, after which the nut will be loose,
because air pressure is a far greater force than the nut, tightened by
hand, can affect.

Jobst Brandt- Hide quoted text -

- Show quoted text -
================================================== =======

Hi Jobst.

I do not know to whom you were replying; perhaps it was to both of us.
All I know about my vlve sparation waqs that it was a prperly matched
size IRC tube for the tire it was in. It had been inflated with a
chuck on a floor pump hose so *NO* pressure was exerted to push the
valve sideways during inflation. There was no valve nut on the tube
either during inflation or after. The valve was straight in the rim
hole. Furthermore the valve separation happened sometime *OVERNIGHT*
whilst the wheel was on the bicycle and the bicycle was off the floor
and supported by two brackets that hold the top tube. It did *NOT*
happen *DURING INFLATION* of the tire but occurred *MANY HOURS (10+)
AFTERWARDS*. The time lag between inflation of the tube and the valve
separation is why I said it must be something that happens from time
to time without any reason.

Cheers from Peter

On Aug 25, 4:15 pm, Jobst Brandt, an egotistical blowhard croaked:


a shy person sniped:

and

Peter who? I don't care how much you ride.


Why don't you just stick this crap where the sun don't shine?

On Aug 25, 5:15*pm, Jobst Brandt wrote:
a shy person sniped:





I've got Mavic Ksyrium SL Premium wheels and my tubes keep
developing a slow leak at the base of the valve stem. *My dealer
suggested using a short piece of rim tape over the valve stem hole
to provide a bit of cushioning and it helped... a little... I got
700 miles before the tubes started to leak instead of only 300
miles without the cushioning. The Mavic web site doesn't seem to
provide any way to ask for technical support so I'm stuck. *Anyone
else ever had this problem, any ideas for a more permanent fix?
One day last week I rode my bicycle and had a great ride. *I came
home and hung the bike by its crossbar on the rack where it lives
when not in use. *The next day i went to ride it and found that the
rear tire was completely deflated. *Investigation showed that there
was a small hole on the base of the reinforced section where the
valve is. *This was an IRC tube and it was on a Ambrosio Evolution
TQB rim. *The tube was the proper size for the tire and no valve nut
was on the tube or used during inflation. *The tire had been
inflated with a floor pump and there had not been any side pressure
exerted on the valve stem during pumping. *There are not any burrs
or sharp edges on the edge of the valve hole in the rim. *It seems
that this is one of those things that just happen from time to time.
Stop making pseudo excuses for rumored mistreatment of inner tubes.
Valve stem nuts and rim valve ports do not cause these leaks. *Leaks
at the valve stem were tube manufacturing flaws that most people
experienced once upon a time and now no longer do because the process
has been corrected. *That so many brands had these flaws at the same
time indicates that they all bought their branded tubes from the same
manufacturer... so much for most brand names.
I am amazed how quick bicyclists were to accept blame for valve stem
related leaks... pounding chest, confessing to misuse and wearing sack
cloth with ashes! *Mea culpa, mea culpa, mea culpa!
Cut it out! *Those of us who have been pumping tires with Silca Impero
frame pumps by hand for ages without leaks know why tube stems have
knurled retention nuts. *They are knurled because they are intended to
be fastened with thumb and forefinger, rather than wrenching tight.
They keep the stem from submerging when a Campagnolo pump head
(without a lever or hose) is used.
As I mentioned, the nut can be tightened as tight as a hand can make
it before inflating to 100 PSI, after which the nut will be loose,
because air pressure is a far greater force than the nut, tightened by
hand, can affect.
I do not know to whom you were replying; perhaps it was to both of us.

I am replying to the writer of the original text and the litany of
"what I didn't do wrong".

You may not be familiar with newsgroup protocol, but the "" marks
give the history of responses, the most recent having only one "" and
you can follow the thread back to the top.

All I know about my valve separation was that it was a properly
matched size IRC tube for the tire it was in. *It had been inflated
with a chuck on a floor pump hose so *NO* pressure was exerted to
push the valve sideways during inflation. *There was no valve nut on
the tube either during inflation or after. *The valve was straight
in the rim hole. *Furthermore the valve separation happened sometime
*OVERNIGHT* whilst the wheel was on the bicycle and the bicycle was
off the floor and supported by two brackets that hold the top tube.
It did *NOT* happen *DURING INFLATION* of the tire but occurred
*MANY HOURS (10+) AFTERWARD*. *The time lag between inflation of
the tube and the valve separation is why I said it must be something
that happens from time to time without any reason.

There you go again listing all the things believed by the "I'm at
fault for the failure" believers.

snipped

That is to what I was replying.

Peter

Peter who? *I don't care how much you ride.

to snipe:

1 :to shoot at exposed individuals (as of an enemy's forces) from a
* *usually concealed point of vantage

Jobst Brandt- Hide quoted text -

- Show quoted text -

Hi Jobst.

No, what I listed was what did or did not happen during inflation of
the tube so that readers would not have to ask what was done. In other
words, I posted the methology I used to inflate the tube so that
others would be able to analyse what might have happened whilst having
a knowledge of what might have lead up to the valve stem separation.

Cheers from Peter

On 25 Aug, 21:12, Sir Ridesalot wrote:
On Aug 24, 10:18*pm, Jobst Brandt wrote:

a shy person sniped:

I've got Mavic Ksyrium SL Premium wheels and my tubes keep
developing a slow leak at the base of the valve stem. *My dealer
suggested using a short piece of rim tape over the valve stem hole
to provide a bit of cushioning and it helped... a little... I got
700 miles before the tubes started to leak instead of only 300
miles without the cushioning. The Mavic web site doesn't seem to
provide any way to ask for technical support so I'm stuck. *Anyone
else ever had this problem, any ideas for a more permanent fix?
One day last week I rode my bicycle and had a great ride. *I came
home and hung the bike by its crossbar on the rack where it lives
when not in use. *The next day i went to ride it and found that the
rear tire was completely deflated. *Investigation showed that there
was a small hole on the base of the reinforced section where the
valve is. *This was an IRC tube and it was on a Ambrosio Evolution
TQB rim. *The tube was the proper size for the tire and no valve nut
was on the tube or used during inflation. *The tire had been
inflated with a floor pump and there had not been any side pressure
exerted on the valve stem during pumping. *There are not any burrs
or sharp edges on the edge of the valve hole in the rim. *It seems
that this is one of those things that just happen from time to time.

Stop making pseudo excuses for rumored mistreatment of inner tubes.
Valve stem nuts and rim valve ports do not cause these leaks. *Leaks
at the valve stem were tube manufacturing flaws that most people
experienced once upon a time and now no longer do because the process
has been corrected. *That so many brands had these flaws at the same
time indicates that they all bought their branded tubes from the same
manufacturer... so much for most brand names.

I am amazed how quick bicyclists were to accept blame for valve stem
related leaks... pounding chest, confessing to misuse and wearing sack
cloth with ashes! *Mea culpa, mea culpa, mea culpa!

Cut it out! *Those of us who have been pumping tires with Silca Impero
frame pumps by hand for ages without leaks know why tube stems have
knurled retention nuts. *They are knurled because they are intended to
be fastened with thumb and forefinger, rather than wrenching tight.
They keep the stem from submerging when a Campagnolo pump head
(without a lever or hose) is used.

As I mentioned, the nut can be tightened as tight as a hand can make
it before inflating to 100 PSI, after which the nut will be loose,
because air pressure is a far greater force than the nut, tightened by
hand, can affect.

Jobst Brandt- Hide quoted text -

- Show quoted text -

================================================== =======

Hi Jobst.

I do not know to whom you were replying; perhaps it was to both of us.
All I know about my vlve sparation waqs that it was a prperly matched
size IRC tube for the tire it was in. It had been inflated with a
chuck on a floor pump hose so *NO* pressure was exerted to push the
valve sideways during inflation. There was no valve nut on the tube
either during inflation or after. The valve was straight in the rim
hole. Furthermore the valve separation happened sometime *OVERNIGHT*
whilst the wheel was on the bicycle and the bicycle was off the floor
and supported by two brackets that hold the top tube. It did *NOT*
happen *DURING INFLATION* of the tire but occurred *MANY HOURS (10+)
AFTERWARDS*. The time lag between inflation of the tube and the valve
separation is why I said it must be something that happens from time
to time without any reason.

Cheers from Peter

I've read your post again and the hole in the reinforcement for the
valve could be due to mineral oil. The contamination may be from your
own inflator or one you have borrowed. It takes a few weeks fort he
oil to rot the rubber.

You hang your bike up so the valve rests at the bottom of the wheel
and any oil on the rim near the valve will drip through the valve
hole. The oil contamination will be more likely on the rear rim.
Either seal the valve stem to the rim with a little mastic or tie the
wheel so the valve is at the top of the wheel, when you hang the bike.

Sir Ridesalot wrote:
On Aug 25, 5:15�pm, Jobst Brandt wrote:
a shy person sniped:





I've got Mavic Ksyrium SL Premium wheels and my tubes keep
developing a slow leak at the base of the valve stem. �My dealer
suggested using a short piece of rim tape over the valve stem hole
to provide a bit of cushioning and it helped... a little... I got
700 miles before the tubes started to leak instead of only 300
miles without the cushioning. The Mavic web site doesn't seem to
provide any way to ask for technical support so I'm stuck. �Anyone
else ever had this problem, any ideas for a more permanent fix?
One day last week I rode my bicycle and had a great ride. �I came
home and hung the bike by its crossbar on the rack where it lives
when not in use. �The next day i went to ride it and found that the
rear tire was completely deflated. �Investigation showed that there
was a small hole on the base of the reinforced section where the
valve is. �This was an IRC tube and it was on a Ambrosio Evolution
TQB rim. �The tube was the proper size for the tire and no valve nut
was on the tube or used during inflation. �The tire had been
inflated with a floor pump and there had not been any side pressure
exerted on the valve stem during pumping. �There are not any burrs
or sharp edges on the edge of the valve hole in the rim. �It seems
that this is one of those things that just happen from time to time.
Stop making pseudo excuses for rumored mistreatment of inner tubes.
Valve stem nuts and rim valve ports do not cause these leaks. �Leaks
at the valve stem were tube manufacturing flaws that most people
experienced once upon a time and now no longer do because the process
has been corrected. �That so many brands had these flaws at the same
time indicates that they all bought their branded tubes from the same
manufacturer... so much for most brand names.
I am amazed how quick bicyclists were to accept blame for valve stem
related leaks... pounding chest, confessing to misuse and wearing sack
cloth with ashes! �Mea culpa, mea culpa, mea culpa!
Cut it out! �Those of us who have been pumping tires with Silca Impero
frame pumps by hand for ages without leaks know why tube stems have
knurled retention nuts. �They are knurled because they are intended to
be fastened with thumb and forefinger, rather than wrenching tight.
They keep the stem from submerging when a Campagnolo pump head
(without a lever or hose) is used.
As I mentioned, the nut can be tightened as tight as a hand can make
it before inflating to 100 PSI, after which the nut will be loose,
because air pressure is a far greater force than the nut, tightened by
hand, can affect.
I do not know to whom you were replying; perhaps it was to both of us.
I am replying to the writer of the original text and the litany of
"what I didn't do wrong".

You may not be familiar with newsgroup protocol, but the "" marks
give the history of responses, the most recent having only one "" and
you can follow the thread back to the top.

All I know about my valve separation was that it was a properly
matched size IRC tube for the tire it was in. �It had been inflated
with a chuck on a floor pump hose so *NO* pressure was exerted to
push the valve sideways during inflation. �There was no valve nut on
the tube either during inflation or after. �The valve was straight
in the rim hole. �Furthermore the valve separation happened sometime
*OVERNIGHT* whilst the wheel was on the bicycle and the bicycle was
off the floor and supported by two brackets that hold the top tube.
It did *NOT* happen *DURING INFLATION* of the tire but occurred
*MANY HOURS (10+) AFTERWARD*. �The time lag between inflation of
the tube and the valve separation is why I said it must be something
that happens from time to time without any reason.
There you go again listing all the things believed by the "I'm at
fault for the failure" believers.

snipped

That is to what I was replying.

Peter
Peter who? �I don't care how much you ride.

to snipe:

1 :to shoot at exposed individuals (as of an enemy's forces) from a
� �usually concealed point of vantage

Jobst Brandt- Hide quoted text -

- Show quoted text -

Hi Jobst.

No, what I listed was what did or did not happen during inflation of
the tube so that readers would not have to ask what was done. In other
words, I posted the methology I used to inflate the tube so that
others would be able to analyse what might have happened whilst having
a knowledge of what might have lead up to the valve stem separation.

Cheers from Peter

ignore that brandt idiot - he's not learned a damned thing since the
1950's and thinks all valve stems still have huge mushroom heads inside.

your problem is simply faulty tubes. switch brand and disgard the stem
nut to make double sure.

Also, installing a rubber grommet, just the right size to fit snugly
over the valve stem, might help. I usually cut such a grommet in half
edgewise, so it's only half as thick.

On 29 Aug, 01:26, Jobst Brandt wrote:
shy Bill wrote:
Also, installing a rubber grommet, just the right size to fit snugly
over the valve stem, might help. *I usually cut such a grommet in
half edgewise, so it's only half as thick.

There you go again putting blame on the user and his "sharp edged
rim". *These are faulty tubes with over cooked valve stems so they are
held only bay fried rubber. *It is not the knurled nut, the rim or the
pump method that causes stem leaks. *Grommets will have no effect on
stem separation.


Stop creating stories JB.
A grommet or O-ring will seal the gap between stem and rim so reducing
the risk of environmental contamination. Rubber tubes will always rot
when exposed to mineral oil. Mineral oil is commonly used on bicyle
chains and drips. With modern derailler geared bikes the largest
sprocket is barely outside of the plane of the rim and oil drips on
the rim are not unheard of. It is likely that ocasionally an drop of
oil will contact the stem and run down to the tube and start the rot.
The oil drip only needs to be near the valve hole when the bike is
stood with the valve at the botttom of the rim for the tube to succumb
to mineral oil degredation. This would clearly be a fault of the user
or bicycle manufacturer and not the inner tube manufacturer or
supplier.

If you use castor oil or a wax mix for chain lubrication then you
should not need to be concious of valve position when standing or
hanging the bike.