Tire-making: bead stress, tire width, math, woe........

On 8/22/2011 9:55 PM, DirtRoadie wrote:


Everyone seems to want to fully adopt one side or the other in this
"belt v. suspenders" discussion. There should really no problem
accepting that there are two mechanism that can work and they can (and
undoubtedly do) work together.


This would seem to be closest to the truth, if you look at the tubeless
adapter kits for MTBs: among the not-tubeless-rated rims and
not-tubeless-rated tires, some combinations work fairly well, while
others are a waste of time.

.....And the people who created the UST design must have seen that the
concept of the rim hooks being the main component keeping the tire on
the rim had "issues",,,, as they went to the cost and hassle of
designing a new rim type with extra-deep hooks.

---------

I also didn't find much on people using tubeless adapter kits on road
bikes (using non-UST rims and tires). Most of the advantages of tubeless
tires (lighter weight, less inch flats) would seem to apply to road
bicycles also.

I got some new car tires a while back and noticed that they speared a
sealant around the bead of the tire before mounting on the wheel. Yet
you never hear of car tire beads slipping over the rim, unless the bead
suffers complete failure. Perhaps the secret to getting reliable
tubeless performance is a bead that /is/ strong enough to carry the
inflation pressure of the tire, even when the bead is lubed with
slippery sealant....

What bicycle rims (26" and/or 700c) are still offered with no bead hooks
at all?

On Tue, 23 Aug 2011 00:57:32 -0700 (PDT), thirty-six
wrote:

On Aug 23, 2:37*am, john B. wrote:
On Mon, 22 Aug 2011 13:32:01 -0700 (PDT), thirty-six



wrote:
On Aug 22, 9:28*pm, DougC wrote:
On 8/22/2011 1:18 PM, thirty-six wrote:

The wire stiffens the connection with the rim so that the tyre stays
in place. *The wire's strength is of no particular importance, it's
the resistance to bending which is key. *...

I don't know if I believe that.

It would mean that you could take a clincher tire and cut both beads
completely through--and then mount & inflate it and still have it stay
on the rim, with just as much pressure as with the beads uncut.

You would be breaking the beam and so the hold of the tyre is
compromised around the cut. * Test it statically. *Do not ride it at
speed.

Obviously the beads are placed under great tension in use, since for
~100 years steel was the only material used and in the last several
decades the only other material used has been kevlar (which is also a
high tensile strength material).

The steel wire is used as a beam for the tyre's unfortunate edge. *The
tubular tyre does not of course suffer from this liability as the
edges are joined together making the tyre essentially edgeless.

Errr... there is no "beam" involved in tire strength.

The bead reinforcement - i.e., the steel or kevlar cable in this case
- is stressed longitudinally, in reference to the cable, as it is used
to prevent the bead stretching.

The rim prevents the tyre's edge from stretching (blowing out) it does
not require assistance from concentric restraint.
The wire simply keeps form for the edge.


What you are saying is that the reinforced bead is not needed in a
bicycle tire..... Makes one wonders why all those stupid people out
there insist in making tires that have reinforced beads, doesn't it?

Kevlar, by the way, is used because it doesn't stretch, not primarily
because it is a high strength material.

It's used to keep the tyre package small because it can withstand
repeated folding without injury. It's used because it's a wonder
material which helps to sell the product.

I'm sure that you have been out in the sun too much - and without a
foam beany, too.

I suggest that you consider that a kevlar reinforced beaded tires is
considerable lighter then the wired ones. A continental Ultra Race -
black skin - 700-23C with a wired bead weighs 270gm. With Kevlar -
220gm., some 20% lighter. Certainly enough lighter to make it sell
better then the heavier version.


Cheers,

John B.

On Mon, 22 Aug 2011 19:55:32 -0700 (PDT), DirtRoadie
wrote:

On Aug 22, 7:37*pm, john B. wrote:
On Mon, 22 Aug 2011 13:32:01 -0700 (PDT), thirty-six





wrote:
On Aug 22, 9:28*pm, DougC wrote:
On 8/22/2011 1:18 PM, thirty-six wrote:

The wire stiffens the connection with the rim so that the tyre stays
in place. *The wire's strength is of no particular importance, it's
the resistance to bending which is key. *...

I don't know if I believe that.

It would mean that you could take a clincher tire and cut both beads
completely through--and then mount & inflate it and still have it stay
on the rim, with just as much pressure as with the beads uncut.

You would be breaking the beam and so the hold of the tyre is
compromised around the cut. * Test it statically. *Do not ride it at
speed.

Obviously the beads are placed under great tension in use, since for
~100 years steel was the only material used and in the last several
decades the only other material used has been kevlar (which is also a
high tensile strength material).

The steel wire is used as a beam for the tyre's unfortunate edge. *The
tubular tyre does not of course suffer from this liability as the
edges are joined together making the tyre essentially edgeless.

Errr... there is no "beam" involved in tire strength.

The bead reinforcement - i.e., the steel or kevlar cable in this case
- is stressed longitudinally, in reference to the cable, as it is used
to prevent the bead stretching.

Everyone seems to want to fully adopt one side or the other in this
"belt v. suspenders" discussion. There should really no problem
accepting that there are two mechanism that can work and they can (and
undoubtedly do) work together.

With NO "hook" at the bead, the bead reinforcement does have to take
on the full responsibility for constraining the forces of air pressure
(and all others) within the tire.

But add a substantial hook and the job of the bead reinforcement
becomes much easier. With a suitable means of securing the tire edge
to the rim (thinking hypothetically) all the way around, the
longitudinal strength/stretch resistance of the bead reinforcement
becomes less important or even unnecessary.

Kevlar, by the way, is used because it doesn't stretch, not primarily
because it is a high strength material.

And very UN-stretchy carbon is also becoming the material of choice.

DR


The whole discussion seems centered on a bicycle wheel, as though
nothing else used rubber wheel covers :-)

More to the point a day or so ago I walked by a tire and hose dealer
who supplied the aircraft. In his front window he had an aircraft tire
- About 5 ft. in diameter - and beside it a section cut from the tire.
the bead reinforcing cable was slightly over 1 inch in diameter.

I wonder what all of those reinforced tire beads are doing out there
if they aren't required. Must be a lot of really stupid tire makers.


Cheers,

John B.

On Aug 23, 6:02*am, john B. wrote:
On Mon, 22 Aug 2011 19:55:32 -0700 (PDT), DirtRoadie





wrote:
On Aug 22, 7:37 pm, john B. wrote:
On Mon, 22 Aug 2011 13:32:01 -0700 (PDT), thirty-six

wrote:
On Aug 22, 9:28 pm, DougC wrote:
On 8/22/2011 1:18 PM, thirty-six wrote:

The wire stiffens the connection with the rim so that the tyre stays
in place. The wire's strength is of no particular importance, it's
the resistance to bending which is key. ...

I don't know if I believe that.

It would mean that you could take a clincher tire and cut both beads
completely through--and then mount & inflate it and still have it stay
on the rim, with just as much pressure as with the beads uncut.

You would be breaking the beam and so the hold of the tyre is
compromised around the cut. Test it statically. Do not ride it at
speed.

Obviously the beads are placed under great tension in use, since for
~100 years steel was the only material used and in the last several
decades the only other material used has been kevlar (which is also a
high tensile strength material).

The steel wire is used as a beam for the tyre's unfortunate edge. The
tubular tyre does not of course suffer from this liability as the
edges are joined together making the tyre essentially edgeless.

Errr... there is no "beam" involved in tire strength.

The bead reinforcement - i.e., the steel or kevlar cable in this case
- is stressed longitudinally, in reference to the cable, as it is used
to prevent the bead stretching.

Everyone seems to want to fully adopt one side or the other in this
"belt v. suspenders" discussion. *There should really no problem
accepting that there are two mechanism that can work and they can (and
undoubtedly do) work together.

With NO "hook" at the bead, the *bead reinforcement does have to take
on the full responsibility for constraining the forces of air pressure
(and all others) within the tire.

But add a substantial hook and the job of the bead reinforcement
becomes much easier. *With a suitable means of securing the tire edge
to the rim (thinking hypothetically) all the way around, *the
longitudinal strength/stretch resistance *of the bead reinforcement
becomes less important or even unnecessary.

Kevlar, by the way, is used because it doesn't stretch, not primarily
because it is a high strength material.

And very UN-stretchy carbon is also becoming the material of choice.

DR

The whole discussion seems centered on a bicycle wheel, as though
nothing else used rubber wheel covers :-)

More to the point a day or so ago I walked by a tire and hose dealer
who supplied the aircraft. In his front window he had an aircraft tire
- About 5 ft. in diameter - and beside it a section cut from the tire.
the bead reinforcing cable was slightly over 1 inch in diameter.

I wonder what all of those reinforced tire beads are doing out there
if they aren't required. Must be a lot of really stupid tire makers.

Sounds like you are a "belt" kinda' guy and gotta' have it - with or
without suspenders.
Yes, we were talking about bicycle wheels which, at present, most
commonly have BOTH a tire with your precious bead reinforcement
material AND a rim with a bead engaging "hook."

Does the aircraft tire you saw have a hooked bead interface? As a more
common comparison, automobile tires do not.
See example:
http://www.offroaders.com/tech/AT-MT...ss-section.gif

So it is of little surprise that they must have a strong bead
reinforcement and has little to do with whether the manufacturers are
smart or stupid.

But that hardly establishes that such a bead reinforcement is
absolutely necessary where there IS a sufficient mechanical (i.e.
hooked or even interlocked) bead interface.
See:
http://bit.ly/nA53me

Belt and/or suspenders, right?

DR

On Aug 23, 12:23*pm, john B. wrote:
On Tue, 23 Aug 2011 00:57:32 -0700 (PDT), thirty-six



wrote:
On Aug 23, 2:37 am, john B. wrote:
On Mon, 22 Aug 2011 13:32:01 -0700 (PDT), thirty-six

wrote:
On Aug 22, 9:28 pm, DougC wrote:
On 8/22/2011 1:18 PM, thirty-six wrote:

The wire stiffens the connection with the rim so that the tyre stays
in place. The wire's strength is of no particular importance, it's
the resistance to bending which is key. ...

I don't know if I believe that.

It would mean that you could take a clincher tire and cut both beads
completely through--and then mount & inflate it and still have it stay
on the rim, with just as much pressure as with the beads uncut.

You would be breaking the beam and so the hold of the tyre is
compromised around the cut. Test it statically. Do not ride it at
speed.

Obviously the beads are placed under great tension in use, since for
~100 years steel was the only material used and in the last several
decades the only other material used has been kevlar (which is also a
high tensile strength material).

The steel wire is used as a beam for the tyre's unfortunate edge. The
tubular tyre does not of course suffer from this liability as the
edges are joined together making the tyre essentially edgeless.

Errr... there is no "beam" involved in tire strength.

The bead reinforcement - i.e., the steel or kevlar cable in this case
- is stressed longitudinally, in reference to the cable, as it is used
to prevent the bead stretching.

The rim prevents the tyre's edge from stretching (blowing out) it does
not require assistance from concentric restraint.
The wire simply keeps form for the edge.

What you are saying is that the reinforced bead is not needed in a
bicycle tire..... Makes one wonders why all those stupid people out
there insist in making tires that have reinforced beads, doesn't it?



Kevlar, by the way, is used because it doesn't stretch, not primarily
because it is a high strength material.

It's used to keep the tyre package small because it can withstand
repeated folding without injury. *It's used because it's a wonder
material which helps to sell the product.

I'm sure that you have been out in the sun too much - and without a
foam beany, too.

I suggest that you consider that a kevlar reinforced beaded tires is
considerable lighter then the wired ones.

That was a leading reason why I initially purchased kevlar wired
tyres.
In time I gained the knowledge that tubulars were lighter, offered
less rolling resistance, more speed, greater cornering forces and were
also foldable and didn't need space age technology to support a
misconstrued construction method encouraged by patent chasing. They
were already pretty much at their zenith, only the funding was short
to obtain the best.

A continental Ultra Race -
black skin - 700-23C with a wired bead weighs 270gm. With Kevlar -
220gm., some 20% lighter. Certainly enough lighter to make it sell
better then the heavier version.

I've 8oz trainig tub's which are tough, that's about 220g (probably
more like 200 now) In conjunction with the sprint rims upon which
they are attatched I can corner faster and climb quicker than skinny
youngste4rs with everlasting super-powers and the space-age equipment
to match. I can probably outsprint most when I'm fresh. Oh yes,
perhaps there's a reason why they are called sprints.

thirty-six writes:

they are attatched I can corner faster and climb quicker than skinny
youngste4rs with everlasting super-powers and the space-age equipment

maybe you can, but its not down to the tyre. Any improvement would be SO
marginal it would be almost impossible to measure.

On Aug 23, 3:48*pm, Simon Lewis wrote:
thirty-six writes:
they are attatched I can corner faster and climb quicker than skinny
youngste4rs with everlasting super-powers and the space-age equipment

maybe you can, but its not down to the tyre. Any improvement would be SO
marginal it would be almost *impossible to measure.


Must be my magical paunch (an organ of immense power) because it's
certainly not my heart or lungs.

On Tue, 23 Aug 2011 06:32:23 -0700 (PDT), DirtRoadie
wrote:

On Aug 23, 6:02*am, john B. wrote:
On Mon, 22 Aug 2011 19:55:32 -0700 (PDT), DirtRoadie





wrote:
On Aug 22, 7:37 pm, john B. wrote:
On Mon, 22 Aug 2011 13:32:01 -0700 (PDT), thirty-six

wrote:
On Aug 22, 9:28 pm, DougC wrote:
On 8/22/2011 1:18 PM, thirty-six wrote:

The wire stiffens the connection with the rim so that the tyre stays
in place. The wire's strength is of no particular importance, it's
the resistance to bending which is key. ...

I don't know if I believe that.

It would mean that you could take a clincher tire and cut both beads
completely through--and then mount & inflate it and still have it stay
on the rim, with just as much pressure as with the beads uncut.

You would be breaking the beam and so the hold of the tyre is
compromised around the cut. Test it statically. Do not ride it at
speed.

Obviously the beads are placed under great tension in use, since for
~100 years steel was the only material used and in the last several
decades the only other material used has been kevlar (which is also a
high tensile strength material).

The steel wire is used as a beam for the tyre's unfortunate edge. The
tubular tyre does not of course suffer from this liability as the
edges are joined together making the tyre essentially edgeless.

Errr... there is no "beam" involved in tire strength.

The bead reinforcement - i.e., the steel or kevlar cable in this case
- is stressed longitudinally, in reference to the cable, as it is used
to prevent the bead stretching.

Everyone seems to want to fully adopt one side or the other in this
"belt v. suspenders" discussion. *There should really no problem
accepting that there are two mechanism that can work and they can (and
undoubtedly do) work together.

With NO "hook" at the bead, the *bead reinforcement does have to take
on the full responsibility for constraining the forces of air pressure
(and all others) within the tire.

But add a substantial hook and the job of the bead reinforcement
becomes much easier. *With a suitable means of securing the tire edge
to the rim (thinking hypothetically) all the way around, *the
longitudinal strength/stretch resistance *of the bead reinforcement
becomes less important or even unnecessary.

Kevlar, by the way, is used because it doesn't stretch, not primarily
because it is a high strength material.

And very UN-stretchy carbon is also becoming the material of choice.

DR

The whole discussion seems centered on a bicycle wheel, as though
nothing else used rubber wheel covers :-)

More to the point a day or so ago I walked by a tire and hose dealer
who supplied the aircraft. In his front window he had an aircraft tire
- About 5 ft. in diameter - and beside it a section cut from the tire.
the bead reinforcing cable was slightly over 1 inch in diameter.

I wonder what all of those reinforced tire beads are doing out there
if they aren't required. Must be a lot of really stupid tire makers.

Sounds like you are a "belt" kinda' guy and gotta' have it - with or
without suspenders.
Yes, we were talking about bicycle wheels which, at present, most
commonly have BOTH a tire with your precious bead reinforcement
material AND a rim with a bead engaging "hook."

Does the aircraft tire you saw have a hooked bead interface? As a more
common comparison, automobile tires do not.
See example:
http://www.offroaders.com/tech/AT-MT...ss-section.gif

So it is of little surprise that they must have a strong bead
reinforcement and has little to do with whether the manufacturers are
smart or stupid.

But that hardly establishes that such a bead reinforcement is
absolutely necessary where there IS a sufficient mechanical (i.e.
hooked or even interlocked) bead interface.
See:
http://bit.ly/nA53me

Belt and/or suspenders, right?

DR

I think that the most powerful rebuttal to your point is that a tire
built without any form of bead reinforcement would be substantially
lighter then a tire built with one and as we all know light is
wonderful in the bicycle world.

If a non-reinforced bead tire could be, say 30 - 40% lighter (kevlar
beaded tires are already about 20% lighter) then would these tires
sell? Like hotcakes on a cold winter morning they'd sell. But I've
never seen such a tire..... I wonder why?

Cheers,

John B.

On Tue, 23 Aug 2011 07:31:59 -0700 (PDT), thirty-six
wrote:

On Aug 23, 12:23*pm, john B. wrote:
On Tue, 23 Aug 2011 00:57:32 -0700 (PDT), thirty-six



wrote:
On Aug 23, 2:37 am, john B. wrote:
On Mon, 22 Aug 2011 13:32:01 -0700 (PDT), thirty-six

wrote:
On Aug 22, 9:28 pm, DougC wrote:
On 8/22/2011 1:18 PM, thirty-six wrote:

The wire stiffens the connection with the rim so that the tyre stays
in place. The wire's strength is of no particular importance, it's
the resistance to bending which is key. ...

I don't know if I believe that.

It would mean that you could take a clincher tire and cut both beads
completely through--and then mount & inflate it and still have it stay
on the rim, with just as much pressure as with the beads uncut.

You would be breaking the beam and so the hold of the tyre is
compromised around the cut. Test it statically. Do not ride it at
speed.

Obviously the beads are placed under great tension in use, since for
~100 years steel was the only material used and in the last several
decades the only other material used has been kevlar (which is also a
high tensile strength material).

The steel wire is used as a beam for the tyre's unfortunate edge. The
tubular tyre does not of course suffer from this liability as the
edges are joined together making the tyre essentially edgeless.

Errr... there is no "beam" involved in tire strength.

The bead reinforcement - i.e., the steel or kevlar cable in this case
- is stressed longitudinally, in reference to the cable, as it is used
to prevent the bead stretching.

The rim prevents the tyre's edge from stretching (blowing out) it does
not require assistance from concentric restraint.
The wire simply keeps form for the edge.

What you are saying is that the reinforced bead is not needed in a
bicycle tire..... Makes one wonders why all those stupid people out
there insist in making tires that have reinforced beads, doesn't it?



Kevlar, by the way, is used because it doesn't stretch, not primarily
because it is a high strength material.

It's used to keep the tyre package small because it can withstand
repeated folding without injury. *It's used because it's a wonder
material which helps to sell the product.

I'm sure that you have been out in the sun too much - and without a
foam beany, too.

I suggest that you consider that a kevlar reinforced beaded tires is
considerable lighter then the wired ones.

That was a leading reason why I initially purchased kevlar wired
tyres.
In time I gained the knowledge that tubulars were lighter, offered
less rolling resistance, more speed, greater cornering forces and were
also foldable and didn't need space age technology to support a
misconstrued construction method encouraged by patent chasing. They
were already pretty much at their zenith, only the funding was short
to obtain the best.

Space age? Made out of stuff extruded by worms.

A continental Ultra Race -
black skin - 700-23C with a wired bead weighs 270gm. With Kevlar -
220gm., some 20% lighter. Certainly enough lighter to make it sell
better then the heavier version.

I've 8oz trainig tub's which are tough, that's about 220g (probably
more like 200 now) In conjunction with the sprint rims upon which
they are attatched I can corner faster and climb quicker than skinny
youngste4rs with everlasting super-powers and the space-age equipment
to match. I can probably outsprint most when I'm fresh. Oh yes,
perhaps there's a reason why they are called sprints.

I can remember back when the magazines were claiming that the clincher
tire would take over the world - why somebody had just used them in a
major race in France..... Today, what? 20 - 30 years later those dumb
bunnies are still using those archaic worm made tires. I wonder
whether carbon will go the same way?

(On the other hand, when I moved back to Bangkok I was averaging 2 - 3
flats in a 10 km. ride with my sew-ups. Easy to change but how many
can you stuff under the seat :-)
Cheers,

John B.

On Tue, 23 Aug 2011 16:48:40 +0200, Simon Lewis
wrote:

thirty-six writes:

they are attatched I can corner faster and climb quicker than skinny
youngste4rs with everlasting super-powers and the space-age equipment

maybe you can, but its not down to the tyre. Any improvement would be SO
marginal it would be almost impossible to measure.

Huh? Try doing, say a 100 miler, with your low pressure, coarse
treaded, off the road tires. Next day change to 1.3" smooth, high
pressure tires and try the same ride.

Cheers,

John B.