This is mostly a philosophical question, but maybe it has a technical answer.
The rim of a bike wheel is a relatively heavy component, largely because
of its circumference. Could it be dispensed with, at least in the case of
a tubular tire, by making the spokes extensions of the tire carcass cords? The hub would remain mostly the same, with the "spoke" cords of the tire laced around anchors on the hub flanges.
It wouldn't be very convenient to handle, indeed, a spider's nightmare.
But, it could fold up much like a parachute. The tire would have to be inflated to a pressure sufficient to support the needed spoke tension,
which might be rather higher than the pressure used in traditional
tubular tires.
It would be hard to manufacture, getting all the spoke lengths matched
to run true being the most obvious difficulty. But intuition suggests
it would be about the lightest construction possible, as well as the
most compact when stowed before use.
Another way of asking the same question is to ask the stiffness of a fully-inflated, unmounted tubular tire compared to a traditional wood
or metal wheel rim.
I've never handled one and so have difficulty guessing.
Thanks for reading, and any insights.
bob prohaska
On 3/13/2025 11:29 AM, bp@www.zefox.net wrote:
This is mostly a philosophical question, but maybe it has a technical answer.
The rim of a bike wheel is a relatively heavy component, largely because
of its circumference. Could it be dispensed with, at least in the case of
a tubular tire, by making the spokes extensions of the tire carcass cords? >> The hub would remain mostly the same, with the "spoke" cords of the tire
laced around anchors on the hub flanges.
It wouldn't be very convenient to handle, indeed, a spider's nightmare.
But, it could fold up much like a parachute. The tire would have to be
inflated to a pressure sufficient to support the needed spoke tension,
which might be rather higher than the pressure used in traditional
tubular tires.
It would be hard to manufacture, getting all the spoke lengths matched
to run true being the most obvious difficulty. But intuition suggests
it would be about the lightest construction possible, as well as the
most compact when stowed before use.
Another way of asking the same question is to ask the stiffness of a
fully-inflated, unmounted tubular tire compared to a traditional wood
or metal wheel rim.
I've never handled one and so have difficulty guessing.
Thanks for reading, and any insights.
bob prohaska
Short answer = no.
A tensioned wheel, (as bicycles wheels with actual tensioned
spokes, not including carbon sheets) has to have a
noncompressible* rim of constant* circumference in order to
not flop around. It's an elegant thing, with among the
highest strength to weight ratios of human built structures.
The principles are similar to an arch:
https://tse2.mm.bing.net/th?id=OIP.OtdqiBPMvo3_wmobAocS0AHaEN&pid=15.1&w=474&h=274&c=7
Tension inward on the spoke is compressing the rim
circumference making a rigid structure. Vertical load on an
arch (keystone) is supported by the sides, with load along a
vector (not vertical as a post and lintel). An arch made of
cooked gnocchi would of course fall apart, as would a
bicycle wheel with a fabric 'rim'.
Pressed steel auto wheels are different, in that there is
not a tension component. The face behaves like an infinite
series of compression spokes (as wooden wheels use) and as
such is heavier for any given strength.
Further to all that:
https://www.astounding.org.uk/ian/wheel/
*practically but not absolutely
AMuzi <am@yellowjersey.org> wrote:
On 3/13/2025 11:29 AM, bp@www.zefox.net wrote:
This is mostly a philosophical question, but maybe it has a technical answer.
The rim of a bike wheel is a relatively heavy component, largely because >>> of its circumference. Could it be dispensed with, at least in the case of >>> a tubular tire, by making the spokes extensions of the tire carcass cords? >>> The hub would remain mostly the same, with the "spoke" cords of the tire >>> laced around anchors on the hub flanges.
It wouldn't be very convenient to handle, indeed, a spider's nightmare.
But, it could fold up much like a parachute. The tire would have to be
inflated to a pressure sufficient to support the needed spoke tension,
which might be rather higher than the pressure used in traditional
tubular tires.
It would be hard to manufacture, getting all the spoke lengths matched
to run true being the most obvious difficulty. But intuition suggests
it would be about the lightest construction possible, as well as the
most compact when stowed before use.
Another way of asking the same question is to ask the stiffness of a
fully-inflated, unmounted tubular tire compared to a traditional wood
or metal wheel rim.
I've never handled one and so have difficulty guessing.
Thanks for reading, and any insights.
bob prohaska
Short answer = no.
A tensioned wheel, (as bicycles wheels with actual tensioned
spokes, not including carbon sheets) has to have a
noncompressible* rim of constant* circumference in order to
not flop around. It's an elegant thing, with among the
highest strength to weight ratios of human built structures.
The principles are similar to an arch:
https://tse2.mm.bing.net/th?id=OIP.OtdqiBPMvo3_wmobAocS0AHaEN&pid=15.1&w=474&h=274&c=7
Tension inward on the spoke is compressing the rim
circumference making a rigid structure. Vertical load on an
arch (keystone) is supported by the sides, with load along a
vector (not vertical as a post and lintel). An arch made of
cooked gnocchi would of course fall apart, as would a
bicycle wheel with a fabric 'rim'.
Pressed steel auto wheels are different, in that there is
not a tension component. The face behaves like an infinite
series of compression spokes (as wooden wheels use) and as
such is heavier for any given strength.
Further to all that:
https://www.astounding.org.uk/ian/wheel/
*practically but not absolutely
Indeed good reasons why spokes haven’t been replaced, much like the chain it’s just too good!
Roger Merriman
On 3/13/2025 1:36 PM, Roger Merriman wrote:
AMuzi <am@yellowjersey.org> wrote:Seems many hate spokes and weight what can we do to get rid of them and
On 3/13/2025 11:29 AM, bp@www.zefox.net wrote:
This is mostly a philosophical question, but maybe it has a technical answer.
The rim of a bike wheel is a relatively heavy component, largely because >>>> of its circumference. Could it be dispensed with, at least in the case of >>>> a tubular tire, by making the spokes extensions of the tire carcass cords? >>>> The hub would remain mostly the same, with the "spoke" cords of the tire >>>> laced around anchors on the hub flanges.
It wouldn't be very convenient to handle, indeed, a spider's nightmare. >>>> But, it could fold up much like a parachute. The tire would have to be >>>> inflated to a pressure sufficient to support the needed spoke tension, >>>> which might be rather higher than the pressure used in traditional
tubular tires.
It would be hard to manufacture, getting all the spoke lengths matched >>>> to run true being the most obvious difficulty. But intuition suggests
it would be about the lightest construction possible, as well as the
most compact when stowed before use.
Another way of asking the same question is to ask the stiffness of a
fully-inflated, unmounted tubular tire compared to a traditional wood
or metal wheel rim.
I've never handled one and so have difficulty guessing.
Thanks for reading, and any insights.
bob prohaska
Short answer = no.
A tensioned wheel, (as bicycles wheels with actual tensioned
spokes, not including carbon sheets) has to have a
noncompressible* rim of constant* circumference in order to
not flop around. It's an elegant thing, with among the
highest strength to weight ratios of human built structures.
The principles are similar to an arch:
https://tse2.mm.bing.net/th?id=OIP.OtdqiBPMvo3_wmobAocS0AHaEN&pid=15.1&w=474&h=274&c=7
Tension inward on the spoke is compressing the rim
circumference making a rigid structure. Vertical load on an
arch (keystone) is supported by the sides, with load along a
vector (not vertical as a post and lintel). An arch made of
cooked gnocchi would of course fall apart, as would a
bicycle wheel with a fabric 'rim'.
Pressed steel auto wheels are different, in that there is
not a tension component. The face behaves like an infinite
series of compression spokes (as wooden wheels use) and as
such is heavier for any given strength.
Further to all that:
https://www.astounding.org.uk/ian/wheel/
*practically but not absolutely
Indeed good reasons why spokes haven’t been replaced, much like the chain >> it’s just too good!
Roger Merriman
my friend, spokes are your friend. I don't use 36 spoke rims I admit but would if I had to and the conditions warranted it. You can ride 36 hole
rim with a bad spoke but try with 20 spoke rim?
On 3/13/2025 1:36 PM, Roger Merriman wrote:
AMuzi <am@yellowjersey.org> wrote:Seems many hate spokes and weight what can we do to get rid
On 3/13/2025 11:29 AM, bp@www.zefox.net wrote:
This is mostly a philosophical question, but maybe it
has a technical answer.
The rim of a bike wheel is a relatively heavy component,
largely because
of its circumference. Could it be dispensed with, at
least in the case of
a tubular tire, by making the spokes extensions of the
tire carcass cords?
The hub would remain mostly the same, with the "spoke"
cords of the tire
laced around anchors on the hub flanges.
It wouldn't be very convenient to handle, indeed, a
spider's nightmare.
But, it could fold up much like a parachute. The tire
would have to be
inflated to a pressure sufficient to support the needed
spoke tension,
which might be rather higher than the pressure used in
traditional
tubular tires.
It would be hard to manufacture, getting all the spoke
lengths matched
to run true being the most obvious difficulty. But
intuition suggests
it would be about the lightest construction possible, as
well as the
most compact when stowed before use.
Another way of asking the same question is to ask the
stiffness of a
fully-inflated, unmounted tubular tire compared to a
traditional wood
or metal wheel rim.
I've never handled one and so have difficulty guessing.
Thanks for reading, and any insights.
bob prohaska
Short answer = no.
A tensioned wheel, (as bicycles wheels with actual tensioned
spokes, not including carbon sheets) has to have a
noncompressible* rim of constant* circumference in order to
not flop around. It's an elegant thing, with among the
highest strength to weight ratios of human built structures.
The principles are similar to an arch:
https://tse2.mm.bing.net/th?
id=OIP.OtdqiBPMvo3_wmobAocS0AHaEN&pid=15.1&w=474&h=274&c=7
Tension inward on the spoke is compressing the rim
circumference making a rigid structure. Vertical load on an
arch (keystone) is supported by the sides, with load along a
vector (not vertical as a post and lintel). An arch made of
cooked gnocchi would of course fall apart, as would a
bicycle wheel with a fabric 'rim'.
Pressed steel auto wheels are different, in that there is
not a tension component. The face behaves like an infinite
series of compression spokes (as wooden wheels use) and as
such is heavier for any given strength.
Further to all that:
https://www.astounding.org.uk/ian/wheel/
*practically but not absolutely
Indeed good reasons why spokes haven’t been replaced, much
like the chain
it’s just too good!
Roger Merriman
of them and my friend, spokes are your friend. I don't use
36 spoke rims I admit but would if I had to and the
conditions warranted it. You can ride 36 hole rim with a bad
spoke but try with 20 spoke rim?
On 3/13/2025 2:36 PM, Roger Merriman wrote:
AMuzi <am@yellowjersey.org> wrote:
On 3/13/2025 11:29 AM, bp@www.zefox.net wrote:
This is mostly a philosophical question, but maybe it has a technical answer.
The rim of a bike wheel is a relatively heavy component, largely because >>>> of its circumference. Could it be dispensed with, at least in the case of >>>> a tubular tire, by making the spokes extensions of the tire carcass cords? >>>> The hub would remain mostly the same, with the "spoke" cords of the tire >>>> laced around anchors on the hub flanges.
It wouldn't be very convenient to handle, indeed, a spider's nightmare. >>>> But, it could fold up much like a parachute. The tire would have to be >>>> inflated to a pressure sufficient to support the needed spoke tension, >>>> which might be rather higher than the pressure used in traditional
tubular tires.
It would be hard to manufacture, getting all the spoke lengths matched >>>> to run true being the most obvious difficulty. But intuition suggests
it would be about the lightest construction possible, as well as the
most compact when stowed before use.
Another way of asking the same question is to ask the stiffness of a
fully-inflated, unmounted tubular tire compared to a traditional wood
or metal wheel rim.
I've never handled one and so have difficulty guessing.
Thanks for reading, and any insights.
bob prohaska
Short answer = no.
A tensioned wheel, (as bicycles wheels with actual tensioned
spokes, not including carbon sheets) has to have a
noncompressible* rim of constant* circumference in order to
not flop around. It's an elegant thing, with among the
highest strength to weight ratios of human built structures.
The principles are similar to an arch:
https://tse2.mm.bing.net/th?id=OIP.OtdqiBPMvo3_wmobAocS0AHaEN&pid=15.1&w=474&h=274&c=7
Tension inward on the spoke is compressing the rim
circumference making a rigid structure. Vertical load on an
arch (keystone) is supported by the sides, with load along a
vector (not vertical as a post and lintel). An arch made of
cooked gnocchi would of course fall apart, as would a
bicycle wheel with a fabric 'rim'.
Pressed steel auto wheels are different, in that there is
not a tension component. The face behaves like an infinite
series of compression spokes (as wooden wheels use) and as
such is heavier for any given strength.
Further to all that:
https://www.astounding.org.uk/ian/wheel/
*practically but not absolutely
Indeed good reasons why spokes haven’t been replaced, much like the chain >> it’s just too good!
"Just too good" applies to a lot on a (roughly) standard bike. As I've
said many times, bike technology is now deep into diminishing returns.
One easy example is weight reduction. Some like Zen are lightweights on
light bikes, but I suspect many posting here have a bike+rider weight of around 200 pounds. For us, a reduction of one pound is only half a
percent - probably undetectable while riding - and it matters only while going uphill or suddenly accelerating.
divergent opinionOn Thu, 13 Mar 2025 16:29:36 -0000 (UTC), bp@www.zefox.net wrote:
This is mostly a philosophical question, but maybe it has a technical answer. >>
The rim of a bike wheel is a relatively heavy component, largely because
of its circumference. Could it be dispensed with, at least in the case of
a tubular tire, by making the spokes extensions of the tire carcass cords? >>The hub would remain mostly the same, with the "spoke" cords of the tire >>laced around anchors on the hub flanges.
It wouldn't be very convenient to handle, indeed, a spider's nightmare. >>But, it could fold up much like a parachute. The tire would have to be >>inflated to a pressure sufficient to support the needed spoke tension, >>which might be rather higher than the pressure used in traditional
tubular tires.
It would be hard to manufacture, getting all the spoke lengths matched
to run true being the most obvious difficulty. But intuition suggests
it would be about the lightest construction possible, as well as the
most compact when stowed before use.
Another way of asking the same question is to ask the stiffness of a >>fully-inflated, unmounted tubular tire compared to a traditional wood
or metal wheel rim.
I've never handled one and so have difficulty guessing.
Thanks for reading, and any insights.
bob prohaska
So if I get a flat tire I have to lace, align, and balance the the new
tire to the hub? I think I'll pass.
divergent opinionOn Thu, 13 Mar 2025 16:29:36 -0000 (UTC), bp@www.zefox.net wrote:
This is mostly a philosophical question, but maybe it has a technical answer.
The rim of a bike wheel is a relatively heavy component, largely because
of its circumference. Could it be dispensed with, at least in the case of
a tubular tire, by making the spokes extensions of the tire carcass cords? >The hub would remain mostly the same, with the "spoke" cords of the tire >laced around anchors on the hub flanges.
It wouldn't be very convenient to handle, indeed, a spider's nightmare.
But, it could fold up much like a parachute. The tire would have to be >inflated to a pressure sufficient to support the needed spoke tension,
which might be rather higher than the pressure used in traditional
tubular tires.
It would be hard to manufacture, getting all the spoke lengths matched
to run true being the most obvious difficulty. But intuition suggests
it would be about the lightest construction possible, as well as the
most compact when stowed before use.
Another way of asking the same question is to ask the stiffness of a >fully-inflated, unmounted tubular tire compared to a traditional wood
or metal wheel rim.
I've never handled one and so have difficulty guessing.
Thanks for reading, and any insights.
bob prohaska
AMuzi <am@yellowjersey.org> wrote:
A tensioned wheel, (as bicycles wheels with actual tensioned
spokes, not including carbon sheets) has to have a
noncompressible* rim of constant* circumference in order to
not flop around. It's an elegant thing, with among the
highest strength to weight ratios of human built structures.
If a tubular tire is inflated to working pressure while not
mounted to a rim does it _not_ become a stiff hoop?
Thanks for writing,
bob prohaska
A tensioned wheel, (as bicycles wheels with actual tensioned
spokes, not including carbon sheets) has to have a
noncompressible* rim of constant* circumference in order to
not flop around. It's an elegant thing, with among the
highest strength to weight ratios of human built structures.
No, it does not. Try it!
Due to the fabric bias, a tubular minor diameter shrinksradically when pressurized (which makes it tight on the rim
in normal use). In midair, they make something close to an
infinity symbol or figure 8 as the minor diameter is reduced.
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