Presta Tube In Schraeder-Drilled Rim: Workaround?

Jay Beattie wrote:

And you will need all 180 because 179 will fall apart shortly after
you open the box. They are made of goat intestines or dead Chinese
dissidents or something like that.

So are the 6 for $1.79 grommets from Home Depot.

I bought 12 $2 digital multimeters at Harbor Freight for a an enrichment
day lesson I did at my son's school on Ohm's law. Being a big believer
in hands-on experiments, I made 12 experimenter boards and had them
measure voltage and current. By the end of the day, 10 of the meters had
blown the fuse for over-current when the kids tried to measure current
directly across two AA batteries. The local electronics store wanted
about $2.50 per fuse for replacements. All Electronics had them 5 for 1$.

On Fri, 21 Mar 2008 15:20:22 -0400, "(PeteCresswell)"
may have said:

Been using Presta-valved tubes in the Schraeder-drilled rims on
my utility bike for years with no problems.

Last couple days, I've torn out two valve stems.

Seems like the bigger hole is putting a load on the rubber around
the base of the stem and there needs tb something more solid to
take that load.

My thought is to screw on a retaining ring all the way so that it
is inside the tire casing when the tube is inflated.

viz: http://tinyurl.com/2zzfsu

That would certainly relieve the stress on the tube.

Nope. It would cause the failure point to move, though.

But what about the tub's having to wrap around it under pressure?

That's the problem, all right.

Anybody done this with success over the long haul?

Better idea: Get the grommets or bushings mentioned elsewhere. If
nothing else, a suitably sized and bent thin washer would be better
than nothing.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Jay Beattie wrote:
On Mar 21, 3:09 pm, SMS wrote:

Harbor Freight sells 180 grommets for $4.99,
"http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=46724".
You just never know when you're going to need a grommet, so keep plenty
on hand.

And you will need all 180 because 179 will fall apart shortly after
you open the box. They are made of goat intestines or dead Chinese
dissidents or something like that. The local Harbor Fright store is
like a weird flea market filled with $15 Chinese circular saws. I
bought a roto-zip knock off I expect to last for about eight minutes,
which is three minutes longer than I need it. -- Jay Beattie.

I started buying HF stuff when I realized that most of the local HW
stores were selling the same Chinese stuff at "traditional" prices. At
least HF sells low-quality tools for low prices. Some of the stuff is
junk, but often a junk tool is what you want anyway (as long as you're
paying junk prices). Other stuff is surprisingly high quality -- you
never know. Sometimes the junky feeling tool turns out to be very
durable, just feels/sounds junky. A lot of the tools need a little
initial tweaking, kind of like cheap wheel sets, once you set them up,
they're fine.

On Fri, 21 Mar 2008 15:20:22 -0400, "(PeteCresswell)" wrote:

My thought is to screw on a retaining ring all the way so that it
is inside the tire casing when the tube is inflated.

There are special rings for this. They consist of a ring slightly higher
than a regular retaining ring, like a retainer ring plus a slimmer
cylindrical bit, which keeps the presta valve centered, as well as inside
the rim.

Jasper

On Fri, 21 Mar 2008 21:30:57 -0700, SMS wrote:

I bought 12 $2 digital multimeters at Harbor Freight for a an enrichment
day lesson I did at my son's school on Ohm's law. Being a big believer
in hands-on experiments, I made 12 experimenter boards and had them
measure voltage and current. By the end of the day, 10 of the meters had
blown the fuse for over-current when the kids tried to measure current
directly across two AA batteries. The local electronics store wanted
about $2.50 per fuse for replacements. All Electronics had them 5 for 1$.

And still the local ele3ctronics stgore is surprised they lose business
and angry about "unfair competition", by which they mean "fair competition
we didn't used to see".

Jasper

On Sat, 22 Mar 2008 14:40:47 -0600, Werehatrack
wrote:
On Fri, 21 Mar 2008 15:20:22 -0400, "(PeteCresswell)"
may have said:

Been using Presta-valved tubes in the Schraeder-drilled rims on
my utility bike for years with no problems.

Last couple days, I've torn out two valve stems.

Seems like the bigger hole is putting a load on the rubber around
the base of the stem and there needs tb something more solid to
take that load.

My thought is to screw on a retaining ring all the way so that it
is inside the tire casing when the tube is inflated.

viz: http://tinyurl.com/2zzfsu

That would certainly relieve the stress on the tube.

Nope. It would cause the failure point to move, though.

But what about the tub's having to wrap around it under pressure?

That's the problem, all right.

It's not. I've got a couple of rims fitted with adapter devices that push
the tube back exactly as far as a retaining-ring-under would. That does
not cause the tubes any distress. They're better than a pure retaining
ring, though, because they're a) guaranteed to be larger than a schraeder
hole (a presta retaining ring is only guaranteed to be larger than a
*presta* hole) and they keep the valve centered in the hole.

Jasper

On Sun, 23 Mar 2008 19:51:28 +0100, Jasper Janssen wrote:

On Fri, 21 Mar 2008 21:30:57 -0700, SMS wrote:

I bought 12 $2 digital multimeters at Harbor Freight for a an enrichment
day lesson I did at my son's school on Ohm's law. Being a big believer
in hands-on experiments, I made 12 experimenter boards and had them
measure voltage and current. By the end of the day, 10 of the meters had
blown the fuse for over-current when the kids tried to measure current
directly across two AA batteries. The local electronics store wanted
about $2.50 per fuse for replacements. All Electronics had them 5 for 1$.

And still the local ele3ctronics stgore is surprised they lose business
and angry about "unfair competition", by which they mean "fair competition
we didn't used to see".

Do know that all fuses are not the same. I have to use the good stuff and it
just isn't cheap. For those meters, sure, pretty well anything will work

Now maybe, just maybe, your store was marking up the usual crap. Probably not.
If most of their business is selling to the trade they're paying a lot more for
them than you think.

Ron

In article PBuFj.1812$vD1.532@trndny09,
Peter Cole wrote:

Jay Beattie wrote:
On Mar 21, 3:09 pm, SMS wrote:

Harbor Freight sells 180 grommets for $4.99,
"http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=46724".
You just never know when you're going to need a grommet, so keep plenty
on hand.

And you will need all 180 because 179 will fall apart shortly after
you open the box. They are made of goat intestines or dead Chinese
dissidents or something like that. The local Harbor Fright store is
like a weird flea market filled with $15 Chinese circular saws. I
bought a roto-zip knock off I expect to last for about eight minutes,
which is three minutes longer than I need it. -- Jay Beattie.

I started buying HF stuff when I realized that most of the local HW
stores were selling the same Chinese stuff at "traditional" prices. At
least HF sells low-quality tools for low prices. Some of the stuff is
junk, but often a junk tool is what you want anyway (as long as you're
paying junk prices). Other stuff is surprisingly high quality -- you
never know. Sometimes the junky feeling tool turns out to be very
durable, just feels/sounds junky. A lot of the tools need a little
initial tweaking, kind of like cheap wheel sets, once you set them up,
they're fine.

A local low budget store stocks for small restaurants.
I bought a grill scraper made in China. It is heavy,
well made, and when struck gives a solid pure tinnnngg.
A great bit of steel. Look closely at the stock and you
can pick up excellent deals.

--
Michael Press

On Sun, 23 Mar 2008 23:06:56 -0400, RonSonic
wrote:
On Sun, 23 Mar 2008 19:51:28 +0100, Jasper Janssen wrote:
On Fri, 21 Mar 2008 21:30:57 -0700, SMS wrote:

I bought 12 $2 digital multimeters at Harbor Freight for a an enrichment
day lesson I did at my son's school on Ohm's law. Being a big believer
in hands-on experiments, I made 12 experimenter boards and had them
measure voltage and current. By the end of the day, 10 of the meters had
blown the fuse for over-current when the kids tried to measure current
directly across two AA batteries. The local electronics store wanted
about $2.50 per fuse for replacements. All Electronics had them 5 for 1$.

And still the local ele3ctronics stgore is surprised they lose business
and angry about "unfair competition", by which they mean "fair competition
we didn't used to see".

Do know that all fuses are not the same. I have to use the good stuff and it
just isn't cheap. For those meters, sure, pretty well anything will work

Now maybe, just maybe, your store was marking up the usual crap. Probably not.
If most of their business is selling to the trade they're paying a lot more for
them than you think.

Yeah. That's not actually true -- or at least the part about fuses not
being the same. Sure, there are different varieties, but pretty much all
the small-format glass fuses are on the order of cents to dimes when
they're at the factory, and all pretty much match specs. They can, of
course, be marked up a couple of hundred percent at each of several
stages, and that's how you get to a couple of bucks each. That, and
selling singletons rather than dozens or grosses, and having All the
ratings (not just V/A, but also in fast/superfast/slow varieties, etc.)
available, rather than just the most common sort.


Jasper

On Sun, 23 Mar 2008 19:55:37 +0100, Jasper Janssen
wrote:
It's not. I've got a couple of rims fitted with adapter devices that push
the tube back exactly as far as a retaining-ring-under would. That does
not cause the tubes any distress. They're better than a pure retaining
ring, though, because they're a) guaranteed to be larger than a schraeder
hole (a presta retaining ring is only guaranteed to be larger than a
*presta* hole) and they keep the valve centered in the hole.

Finally managed to find it in the catalog.

http://www.roseversand.de/output/con...lnummer=493298

80 eurocents (about a buck 20 today) for two. Note that the picture, as
shown, doesn't actually work -- the valve would push it more than clear of
the hole. You need to put it on the valve before you insert it, upside
down, and then it works perfectly. And unlike a grommet, this one will
stay with you for life, unless you throw it away.

Jasper