simple way to keep presta valves from tearing loose

35 years and it's only now that I'm figuring some things out. No question
that lightweight presta tubes are prone to being pulled apart at the base of
the valve when the pump head is being pulled off. Even if it doesn't happen
right then, it's weakened each time you inflate the tire.

There is a simple "DOH!"-type solution. When pulling the pump head off, push
the valve against the side of the rim. The threads on the valve stem will
stabilize the valve, preventing it from being pulled away from the tube.
Obviously, this only works with threaded valve stems.

My guess is that everyone in the world already knew this but me.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

There is a simple "DOH!"-type solution. When pulling thepumphead off, push
the valve against the side of the rim. The threads on the valve stem will
stabilize the valve, preventing it from being pulled away from the tube.
Obviously, this only works with threaded valve stems.

My guess is that everyone in the world already knew this but me.

Mike -

My solution, something like yours, has been to get a solid grip on the
"ring" that you screw down the length of the presta valve and pull it
towards the wheel as I remove the pump. Haven't had a tube fail at
that junction is a very long time.

Gunni

Mike Jacoubowsky wrote:
35 years and it's only now that I'm figuring some things out. No question
that lightweight presta tubes are prone to being pulled apart at the base of
the valve when the pump head is being pulled off. Even if it doesn't happen
right then, it's weakened each time you inflate the tire.

There is a simple "DOH!"-type solution. When pulling the pump head off, push
the valve against the side of the rim. The threads on the valve stem will
stabilize the valve, preventing it from being pulled away from the tube.
Obviously, this only works with threaded valve stems.

My guess is that everyone in the world already knew this but me.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA



Must be the pumps I use, but the presta valves don't grab the pump after
the clamp is released -- Schrader valves do, though, but I've never had
one fail at the valve.

On Sat, 23 Aug 2008 20:30:37 -0700, "Mike Jacoubowsky"
wrote:

35 years and it's only now that I'm figuring some things out. No question
that lightweight presta tubes are prone to being pulled apart at the base of
the valve when the pump head is being pulled off. Even if it doesn't happen
right then, it's weakened each time you inflate the tire.

There is a simple "DOH!"-type solution. When pulling the pump head off, push
the valve against the side of the rim. The threads on the valve stem will
stabilize the valve, preventing it from being pulled away from the tube.
Obviously, this only works with threaded valve stems.

My guess is that everyone in the world already knew this but me.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

I've never had a failure when pulling the pump off the valve stem. My
failures always occur on the road when I have to air up my replacement
tube to do a flat while out riding. Once I get up around 100 PSI the
frame pump wggles around so much while being pumped that every so
often it wiggles just a little too much and rips the stem loose.

At that point a few choice curse words rip loose from my mouth. It
always happens 15 miles from home, on a cloudless HHOOTT sunny day, on
an asphault road that is busy with truck traffic. All that makes for
a hot miserable time trying to find the puncture in the flat tube that
I now have to repair.

Ever try walking home 15 miles in hot weather on burning hot asphault?
Not fun. I've had to do it and I say again, not fun.

Navigator wrote:
On Sat, 23 Aug 2008 20:30:37 -0700, "Mike Jacoubowsky"
wrote:

35 years and it's only now that I'm figuring some things out. No question
that lightweight presta tubes are prone to being pulled apart at the base of
the valve when the pump head is being pulled off. Even if it doesn't happen
right then, it's weakened each time you inflate the tire.

There is a simple "DOH!"-type solution. When pulling the pump head off, push
the valve against the side of the rim. The threads on the valve stem will
stabilize the valve, preventing it from being pulled away from the tube.
Obviously, this only works with threaded valve stems.

My guess is that everyone in the world already knew this but me.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

I've never had a failure when pulling the pump off the valve stem. My
failures always occur on the road when I have to air up my replacement
tube to do a flat while out riding. Once I get up around 100 PSI the
frame pump wggles around so much while being pumped that every so
often it wiggles just a little too much and rips the stem loose.

At that point a few choice curse words rip loose from my mouth. It
always happens 15 miles from home, on a cloudless HHOOTT sunny day, on
an asphault road that is busy with truck traffic. All that makes for
a hot miserable time trying to find the puncture in the flat tube that
I now have to repair.

Ever try walking home 15 miles in hot weather on burning hot asphault?
Not fun. I've had to do it and I say again, not fun.


I hate to blame the victim, but unless it's a bad stem, it shouldn't
fail from pumping. It's hard not to put stress on the valve when pumping
a wheel that's on the bike, but if it's off, and you're "pumping into
your fist" with the wheel vertical and supporting its own weight, you
can't really put any sideways force on the stem.

On Mon, 25 Aug 2008 00:24:23 GMT, Peter Cole
wrote:

Navigator wrote:
On Sat, 23 Aug 2008 20:30:37 -0700, "Mike Jacoubowsky"
wrote:

35 years and it's only now that I'm figuring some things out. No question
that lightweight presta tubes are prone to being pulled apart at the base of
the valve when the pump head is being pulled off. Even if it doesn't happen
right then, it's weakened each time you inflate the tire.

There is a simple "DOH!"-type solution. When pulling the pump head off, push
the valve against the side of the rim. The threads on the valve stem will
stabilize the valve, preventing it from being pulled away from the tube.
Obviously, this only works with threaded valve stems.

My guess is that everyone in the world already knew this but me.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

I've never had a failure when pulling the pump off the valve stem. My
failures always occur on the road when I have to air up my replacement
tube to do a flat while out riding. Once I get up around 100 PSI the
frame pump wggles around so much while being pumped that every so
often it wiggles just a little too much and rips the stem loose.

At that point a few choice curse words rip loose from my mouth. It
always happens 15 miles from home, on a cloudless HHOOTT sunny day, on
an asphault road that is busy with truck traffic. All that makes for
a hot miserable time trying to find the puncture in the flat tube that
I now have to repair.

Ever try walking home 15 miles in hot weather on burning hot asphault?
Not fun. I've had to do it and I say again, not fun.


I hate to blame the victim, but unless it's a bad stem, it shouldn't
fail from pumping. It's hard not to put stress on the valve when pumping
a wheel that's on the bike, but if it's off, and you're "pumping into
your fist" with the wheel vertical and supporting its own weight, you
can't really put any sideways force on the stem.

What a load of crap. I've had the wheel upright and on the groud
while pumping with my old Zefal frame pump. I've left it on the bike.
By the time I'm up at around 100 PSI, you can't control the pump head
real well and it is going to wiggle no matter HOW much you try and
control it. Period.

On Sat, 23 Aug 2008 20:30:37 -0700, "Mike Jacoubowsky"
wrote:

35 years and it's only now that I'm figuring some things out. No question
that lightweight presta tubes are prone to being pulled apart at the base of
the valve when the pump head is being pulled off. Even if it doesn't happen
right then, it's weakened each time you inflate the tire.

There is a simple "DOH!"-type solution. When pulling the pump head off, push
the valve against the side of the rim. The threads on the valve stem will
stabilize the valve, preventing it from being pulled away from the tube.
Obviously, this only works with threaded valve stems.

My guess is that everyone in the world already knew this but me.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA


I just switched to Presta a few months ago, so thanks for the heads-up.

Ben

On Aug 25, 8:05*pm, Navigator wrote:
On Mon, 25 Aug 2008 00:24:23 GMT, Peter Cole
wrote:

I hate to blame the victim, but unless it's a bad stem, it shouldn't
fail from pumping. It's hard not to put stress on the valve when pumping
a wheel that's on the bike, but if it's off, and you're "pumping into
your fist" with the wheel vertical and supporting its own weight, you
can't really put any sideways force on the stem.

What a load of crap. *I've had the wheel upright and on the groud
while pumping with my old Zefal frame pump. *I've left it on the bike.
By the time I'm up at around 100 PSI, you can't control the pump head
real well and it is going to wiggle no matter HOW much you try and
control it. *Period.

Try bracing your hand against your knee - that is, the hand holding
the pump head. Alternately, try wrapping one finger of that hand
around the rim and tire, to keep the hand stationary with respect to
the valve. The pump head may wiggle a bit, but in my experience, it
won't do any damage.

FWIW, I'm reading these tales of woe and wondering yet again about
others' problems vs. my good luck. In 35+ years of cycling and
thousands of tire inflations, I've never torn either a presta or
schrader valve.

- Frank Krygowski

On Aug 23, 10:30*pm, "Mike Jacoubowsky"
wrote:
35 years and it's only now that I'm figuring some things out. No question
that lightweight presta tubes are prone to being pulled apart at the base of
the valve when the pump head is being pulled off. Even if it doesn't happen
right then, it's weakened each time you inflate the tire.

No doubt that's true. I replace my presta equipped bike's tubes yearly
for that very reason. I've found sizing up one size tube helps. I run
35mm tubes in my 32mm Paselas--and they inflate to fit perfectly
without any stretching, which keeps the valve area less stressed.
Probably keeps me from puncturing as well. I'll give your method a go
as well.

Navigator wrote:
On Mon, 25 Aug 2008 00:24:23 GMT, Peter Cole
wrote:

I hate to blame the victim, but unless it's a bad stem, it shouldn't
fail from pumping. It's hard not to put stress on the valve when pumping
a wheel that's on the bike, but if it's off, and you're "pumping into
your fist" with the wheel vertical and supporting its own weight, you
can't really put any sideways force on the stem.

What a load of crap. I've had the wheel upright and on the groud
while pumping with my old Zefal frame pump. I've left it on the bike.
By the time I'm up at around 100 PSI, you can't control the pump head
real well and it is going to wiggle no matter HOW much you try and
control it. Period.


I think you misread my post. If the wheel is off the bike and vertical,
supporting its own weight with the valve at the top, any wiggle will
simply rock the wheel back & forth and the only force you can develop is
proportional to the wheel mass. That will not be enough to damage the
valve. Zefal frame pumps are all I've ever used.