Interesting track crashes

On Wednesday, December 26, 2018 at 5:59:28 PM UTC-8, Frank Krygowski wrote:
On 12/26/2018 3:02 PM, wrote:

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.

Damn. Mine's 32 years old. I'll have to travel back to 1996 and get rid
of it.

But then I won't be able to ride it across the U.S. in 2003. What to do??

--
- Frank Krygowski

Another example of the engineer who judges things by a single example. Where was it you were educated where they would teach that again?

On Wednesday, December 26, 2018 at 6:21:44 PM UTC-8, James wrote:
On 27/12/18 11:22 am, John B. Slocomb wrote:
On Wed, 26 Dec 2018 12:02:58 -0800 (PST), wrote:

On Thursday, November 29, 2018 at 1:25:28 PM UTC-8, Sir Ridesalot wrote:
An interesting video of track bicycles crashing. Amazing what happens when a tubular tire comes off the rim. I was surprised at how long one rider stayed up - he was okay until the front tire went under his rear wheel.

I saw bits flying around in some of the crashes but couldn't make out what those bits were.

https://www.youtube.com/watch?v=tf17hFikqrQ

Cheers

Track tubulars are paper thin so flats from overheating aren't all that uncommon. My friend who has turned into a total anti-carbon fiber nut sent me a video link to a subject he called "carbon fiber rim exploding under track rider." That isn't what I would have called it. If you look at it closely it looks like a track tandem gets a flat in the final sprint which throws the entire weight of the team unto the front disk which slowly comes apart as the tire peels off.

I showed him that foregoing manufacturing errors that all of the bicycle materials have approximately the same loaded lifespan. That was sort of surprising to me since I have a lot of steel bikes and never had a failure. But I suppose I usually buy them with very little use and they simply don't have that many miles.

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.

Interesting.
Of course Sheldon Brown, that sneaky devil, describes a study
conducted by EFBe (Engineering for Bikes) which is now, I believe, one
of the main elements of the DIN 79100 bicycle-testing standard, which
was published in TOUR magazine of Oct 1997 ( more then 20 years ago)
that demonstrated that two of the three frames that completed the test
with no failures were welded aluminum frames. Two out of three... lets
see, that is about 66.666 %, isn't it?

The Christian Bible has a phrase that seems to apply here (Proverbs
17:28. New International Version)

"Even a fool is thought wise if he keeps silent, and discerning if he
holds his tongue."



It is silly to claim a particular material is prone to failure, when the
reliability is so heavily influenced by the design, construction, and use..

--
JS

I would agree to a certain extent. But we're talking about road racing bikes and hence they were built to the lightest possible specification and were subjected to the highest possible loadings.

Let me remind you that Boeing chose carbon fiber over aluminum for reasons other than weight. Of course it is easier to build aircraft components out of CF since most of the parts can be more carefully observed for manufacturing errors.

On Fri, 28 Dec 2018 14:41:12 -0800 (PST), wrote:

On Wednesday, December 26, 2018 at 4:22:08 PM UTC-8, John B. Slocomb wrote:
On Wed, 26 Dec 2018 12:02:58 -0800 (PST), wrote:

On Thursday, November 29, 2018 at 1:25:28 PM UTC-8, Sir Ridesalot wrote:
An interesting video of track bicycles crashing. Amazing what happens when a tubular tire comes off the rim. I was surprised at how long one rider stayed up - he was okay until the front tire went under his rear wheel.

I saw bits flying around in some of the crashes but couldn't make out what those bits were.

https://www.youtube.com/watch?v=tf17hFikqrQ

Cheers

Track tubulars are paper thin so flats from overheating aren't all that uncommon. My friend who has turned into a total anti-carbon fiber nut sent me a video link to a subject he called "carbon fiber rim exploding under track rider." That isn't what I would have called it. If you look at it closely it looks like a track tandem gets a flat in the final sprint which throws the entire weight of the team unto the front disk which slowly comes apart as the tire peels off.

I showed him that foregoing manufacturing errors that all of the bicycle materials have approximately the same loaded lifespan. That was sort of surprising to me since I have a lot of steel bikes and never had a failure. But I suppose I usually buy them with very little use and they simply don't have that many miles.

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.

Interesting.
Of course Sheldon Brown, that sneaky devil, describes a study
conducted by EFBe (Engineering for Bikes) which is now, I believe, one
of the main elements of the DIN 79100 bicycle-testing standard, which
was published in TOUR magazine of Oct 1997 ( more then 20 years ago)
that demonstrated that two of the three frames that completed the test
with no failures were welded aluminum frames. Two out of three... lets
see, that is about 66.666 %, isn't it?

The Christian Bible has a phrase that seems to apply here (Proverbs
17:28. New International Version)

"Even a fool is thought wise if he keeps silent, and discerning if he
holds his tongue."

cheers,

John B.

Of course anyone with any training would understand that this testing meant nothing. While the test itself was well designed using a single example of each frame yielded no more information that THAT single example.

But then you're the sort of engineer who would build a bridge without actually testing the components of it.

I see... first you condemn a test to failure as it tests only one
example and then you refer to testing bridge components.

Tom, you are a fool. Or do you actually believe that each component of
a bridge is tested to failure... before it is used?

I worked for a company that specialized in contacting with
international oil companies to build and.or maintain oil fields in
remote areas and in doing so we built innumerable bridges and I'm
sorry to inform you that we never tested the components of any of the
bridges... never. And I can assure you that none of the bridges ever
fell down.

I might add, that as we were in business for over 20 years, and as oil
companies were still giving us contacts it is patently obvious that we
knew what we were doing as oil companies don't renew contacts to
companies that build bridges that fall down.

I keep telling you, "It's better to keep your mouth shut and appear
stupid than open it and remove all doubt" and you don't listen.

cheers,

John B.

On Fri, 28 Dec 2018 14:49:08 -0800 (PST), wrote:

On Wednesday, December 26, 2018 at 6:21:44 PM UTC-8, James wrote:
On 27/12/18 11:22 am, John B. Slocomb wrote:
On Wed, 26 Dec 2018 12:02:58 -0800 (PST), wrote:

On Thursday, November 29, 2018 at 1:25:28 PM UTC-8, Sir Ridesalot wrote:
An interesting video of track bicycles crashing. Amazing what happens when a tubular tire comes off the rim. I was surprised at how long one rider stayed up - he was okay until the front tire went under his rear wheel.

I saw bits flying around in some of the crashes but couldn't make out what those bits were.

https://www.youtube.com/watch?v=tf17hFikqrQ

Cheers

Track tubulars are paper thin so flats from overheating aren't all that uncommon. My friend who has turned into a total anti-carbon fiber nut sent me a video link to a subject he called "carbon fiber rim exploding under track rider." That isn't what I would have called it. If you look at it closely it looks like a track tandem gets a flat in the final sprint which throws the entire weight of the team unto the front disk which slowly comes apart as the tire peels off.

I showed him that foregoing manufacturing errors that all of the bicycle materials have approximately the same loaded lifespan. That was sort of surprising to me since I have a lot of steel bikes and never had a failure. But I suppose I usually buy them with very little use and they simply don't have that many miles.

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.

Interesting.
Of course Sheldon Brown, that sneaky devil, describes a study
conducted by EFBe (Engineering for Bikes) which is now, I believe, one
of the main elements of the DIN 79100 bicycle-testing standard, which
was published in TOUR magazine of Oct 1997 ( more then 20 years ago)
that demonstrated that two of the three frames that completed the test
with no failures were welded aluminum frames. Two out of three... lets
see, that is about 66.666 %, isn't it?

The Christian Bible has a phrase that seems to apply here (Proverbs
17:28. New International Version)

"Even a fool is thought wise if he keeps silent, and discerning if he
holds his tongue."



It is silly to claim a particular material is prone to failure, when the
reliability is so heavily influenced by the design, construction, and use.

--
JS

I would agree to a certain extent. But we're talking about road racing bikes and hence they were built to the lightest possible specification and were subjected to the highest possible loadings.

Let me remind you that Boeing chose carbon fiber over aluminum for reasons other than weight. Of course it is easier to build aircraft components out of CF since most of the parts can be more carefully observed for manufacturing errors.

Boeing chose Carbon fiber as parts can be made both lighter AND
stronger then aluminum components.
See
https://www.bbc.com/news/business-25833264
"Instead today's latest planes like Boeing's 787 Dreamliner and
Airbus's A350 rely on lightweight carbon fibre composites - woven mats
of carbon which are embedded in plastic.

The key to a composite material like carbon fibre is that it is
incredibly strong for its weight."
https://www.boeing.com/commercial/ae...icle_04_2.html
"The result is an airframe comprising nearly half carbon fiber
reinforced plastic and other composites. This approach offers weight
savings on average of 20 percent compared to more conventional
aluminum designs."
https://www.thebalancecareers.com/co...ructure-282777
"Weight reduction is the single greatest advantage of composite
material usage and is the key factor in using it in aircraft
structure. Fiber-reinforced matrix systems are stronger than
traditional aluminum found on most aircraft, and they provide a smooth
surface and increase fuel efficiency, which is a huge benefit."

Tom, there is an Indian proverb that seems to describe your antics
with rather embarrassing explicitly:
"The fool who knows his foolishness is wise at least to that extent;
but the fool who thinks himself wise is called a fool indeed."

cheers,

John B.

On 12/28/2018 6:00 PM, John B. Slocomb wrote:
On Fri, 28 Dec 2018 14:41:12 -0800 (PST), wrote:

On Wednesday, December 26, 2018 at 4:22:08 PM UTC-8, John B. Slocomb wrote:
On Wed, 26 Dec 2018 12:02:58 -0800 (PST), wrote:

On Thursday, November 29, 2018 at 1:25:28 PM UTC-8, Sir Ridesalot wrote:
An interesting video of track bicycles crashing. Amazing what happens when a tubular tire comes off the rim. I was surprised at how long one rider stayed up - he was okay until the front tire went under his rear wheel.

I saw bits flying around in some of the crashes but couldn't make out what those bits were.

https://www.youtube.com/watch?v=tf17hFikqrQ

Cheers

Track tubulars are paper thin so flats from overheating aren't all that uncommon. My friend who has turned into a total anti-carbon fiber nut sent me a video link to a subject he called "carbon fiber rim exploding under track rider." That isn't what I would have called it. If you look at it closely it looks like a track tandem gets a flat in the final sprint which throws the entire weight of the team unto the front disk which slowly comes apart as the tire peels off.

I showed him that foregoing manufacturing errors that all of the bicycle materials have approximately the same loaded lifespan. That was sort of surprising to me since I have a lot of steel bikes and never had a failure. But I suppose I usually buy them with very little use and they simply don't have that many miles.

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.

Interesting.
Of course Sheldon Brown, that sneaky devil, describes a study
conducted by EFBe (Engineering for Bikes) which is now, I believe, one
of the main elements of the DIN 79100 bicycle-testing standard, which
was published in TOUR magazine of Oct 1997 ( more then 20 years ago)
that demonstrated that two of the three frames that completed the test
with no failures were welded aluminum frames. Two out of three... lets
see, that is about 66.666 %, isn't it?

The Christian Bible has a phrase that seems to apply here (Proverbs
17:28. New International Version)

"Even a fool is thought wise if he keeps silent, and discerning if he
holds his tongue."

cheers,

John B.

Of course anyone with any training would understand that this testing meant nothing. While the test itself was well designed using a single example of each frame yielded no more information that THAT single example.

But then you're the sort of engineer who would build a bridge without actually testing the components of it.

I see... first you condemn a test to failure as it tests only one
example and then you refer to testing bridge components.

Tom, you are a fool. Or do you actually believe that each component of
a bridge is tested to failure... before it is used?

I worked for a company that specialized in contacting with
international oil companies to build and.or maintain oil fields in
remote areas and in doing so we built innumerable bridges and I'm
sorry to inform you that we never tested the components of any of the
bridges... never. And I can assure you that none of the bridges ever
fell down.

I might add, that as we were in business for over 20 years, and as oil
companies were still giving us contacts it is patently obvious that we
knew what we were doing as oil companies don't renew contacts to
companies that build bridges that fall down.

I keep telling you, "It's better to keep your mouth shut and appear
stupid than open it and remove all doubt" and you don't listen.


Indonesia may have some regard for human life and
engineering standards. Not everyone does:

https://am1590theanswer.com/news/nat...10-years-later

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On 12/28/2018 5:42 PM, wrote:
On Wednesday, December 26, 2018 at 5:59:28 PM UTC-8, Frank Krygowski wrote:
On 12/26/2018 3:02 PM, wrote:

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.

Damn. Mine's 32 years old. I'll have to travel back to 1996 and get rid
of it.

But then I won't be able to ride it across the U.S. in 2003. What to do??

--
- Frank Krygowski

Another example of the engineer who judges things by a single example. Where was it you were educated where they would teach that again?

"never keep an aluminum frame for more than 10 years max" refers to
"never" - as in, "not once, not even with one example."

To understand that, one doesn't even need to get into the realm of
engineering. That just requires the English language and elementary
logic. And the advice can be disproved by one counterexample.

Now if you want to get into engineering, we can talk about normal
curves, failure distributions, statistics, differences in design and more.

As usual, it would save time if you would just say that the "Come [sic]
sources" you referred to were wrong, if not imaginary.

Or hell, just deflect with a change of subject, as you usually do in
these situations.

--
- Frank Krygowski

On 12/28/2018 5:41 PM, wrote:
On Wednesday, December 26, 2018 at 4:22:08 PM UTC-8, John B. Slocomb wrote:
On Wed, 26 Dec 2018 12:02:58 -0800 (PST), wrote:

On Thursday, November 29, 2018 at 1:25:28 PM UTC-8, Sir Ridesalot wrote:
An interesting video of track bicycles crashing. Amazing what happens when a tubular tire comes off the rim. I was surprised at how long one rider stayed up - he was okay until the front tire went under his rear wheel.

I saw bits flying around in some of the crashes but couldn't make out what those bits were.

https://www.youtube.com/watch?v=tf17hFikqrQ

Cheers

Track tubulars are paper thin so flats from overheating aren't all that uncommon. My friend who has turned into a total anti-carbon fiber nut sent me a video link to a subject he called "carbon fiber rim exploding under track rider." That isn't what I would have called it. If you look at it closely it looks like a track tandem gets a flat in the final sprint which throws the entire weight of the team unto the front disk which slowly comes apart as the tire peels off.

I showed him that foregoing manufacturing errors that all of the bicycle materials have approximately the same loaded lifespan. That was sort of surprising to me since I have a lot of steel bikes and never had a failure. But I suppose I usually buy them with very little use and they simply don't have that many miles.

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.

Interesting.
Of course Sheldon Brown, that sneaky devil, describes a study
conducted by EFBe (Engineering for Bikes) which is now, I believe, one
of the main elements of the DIN 79100 bicycle-testing standard, which
was published in TOUR magazine of Oct 1997 ( more then 20 years ago)
that demonstrated that two of the three frames that completed the test
with no failures were welded aluminum frames. Two out of three... lets
see, that is about 66.666 %, isn't it?

The Christian Bible has a phrase that seems to apply here (Proverbs
17:28. New International Version)

"Even a fool is thought wise if he keeps silent, and discerning if he
holds his tongue."

cheers,

John B.

Of course anyone with any training would understand that this testing meant nothing. While the test itself was well designed using a single example of each frame yielded no more information that THAT single example.

But then you're the sort of engineer who would build a bridge without actually testing the components of it.

?? Tom, did you learn bridge design from this cartoon?
https://www.gocomics.com/calvinandhobbes/1986/11/26

--
- Frank Krygowski

On 12/28/2018 7:35 PM, AMuzi wrote:
On 12/28/2018 6:00 PM, John B. Slocomb wrote:
On Fri, 28 Dec 2018 14:41:12 -0800 (PST), wrote:

On Wednesday, December 26, 2018 at 4:22:08 PM UTC-8, John B. Slocomb
wrote:
On Wed, 26 Dec 2018 12:02:58 -0800 (PST), wrote:

On Thursday, November 29, 2018 at 1:25:28 PM UTC-8, Sir Ridesalot
wrote:
An interesting video of track bicycles crashing. Amazing what
happens when a tubular tire comes off the rim. I was surprised at
how long one rider stayed up - he was okay until the front tire
went under his rear wheel.

I saw bits flying around in some of the crashes but couldn't make
out what those bits were.

https://www.youtube.com/watch?v=tf17hFikqrQ

Cheers

Track tubulars are paper thin so flats from overheating aren't all
that uncommon. My friend who has turned into a total anti-carbon
fiber nut sent me a video link to a subject he called "carbon fiber
rim exploding under track rider." That isn't what I would have
called it. If you look at it closely it looks like a track tandem
gets a flat in the final sprint which throws the entire weight of
the team unto the front disk which slowly comes apart as the tire
peels off.

I showed him that foregoing manufacturing errors that all of the
bicycle materials have approximately the same loaded lifespan. That
was sort of surprising to me since I have a lot of steel bikes and
never had a failure. But I suppose I usually buy them with very
little use and they simply don't have that many miles.

Actually the most common frame material to fail is aluminum. Come
sources say never keep an aluminum frame for more than 10 years
max. And the failures are highly reminiscent of the Internet
pictures of carbon fiber failures save that the CF bikes usually
have been hit by cars whereas the AL bikes simply fall apart.

Interesting.
Of course Sheldon Brown, that sneaky devil, describes a study
conducted by EFBe (Engineering for Bikes) which is now, I believe, one
of the main elements of the DIN 79100 bicycle-testing standard, which
was published in TOUR magazine of Oct 1997 ( more then 20 years ago)
that demonstrated that two of the three frames that completed the test
with no failures were welded aluminum frames. Two out of three... lets
see, that is about 66.666 %, isn't it?

The Christian Bible has a phrase that seems to apply here (Proverbs
17:28. New International Version)

"Even a fool is thought wise if he keeps silent, and discerning if he
holds his tongue."

cheers,

John B.

Of course anyone with any training would understand that this testing
meant nothing. While the test itself was well designed using a single
example of each frame yielded no more information that THAT single
example.

But then you're the sort of engineer who would build a bridge without
actually testing the components of it.

I see... first you condemn a test to failure as it tests only one
example and then you refer to testing bridge components.

Tom, you are a fool. Or do you actually believe that each component of
a bridge is tested to failure... before it is used?

I worked for a company that specialized in contacting with
international oil companies to build and.or maintain oil fields in
remote areas and in doing so we built innumerable bridges and I'm
sorry to inform you that we never tested the components of any of the
bridges... never. And I can assure you that none of the bridges ever
fell down.

I might add, that as we were in business for over 20 years, and as oil
companies were still giving us contacts it is patently obvious that we
knew what we were doing as oil companies don't renew contacts to
companies that build bridges that fall down.

I keep telling you, "It's better to keep your mouth shut and appear
stupid than open it and remove all doubt" and you don't listen.


Indonesia may have some regard for human life and engineering standards.
Not everyone does:

https://am1590theanswer.com/news/nat...10-years-later

"...federal funding has been 'pretty stagnant,' but about 20 states
raised taxes to increase their bridge spending."

Where are the "No new taxes" guys?


--
- Frank Krygowski

On Fri, 28 Dec 2018 18:35:48 -0600, AMuzi wrote:

On 12/28/2018 6:00 PM, John B. Slocomb wrote:
On Fri, 28 Dec 2018 14:41:12 -0800 (PST), wrote:

On Wednesday, December 26, 2018 at 4:22:08 PM UTC-8, John B. Slocomb wrote:
On Wed, 26 Dec 2018 12:02:58 -0800 (PST), wrote:

On Thursday, November 29, 2018 at 1:25:28 PM UTC-8, Sir Ridesalot wrote:
An interesting video of track bicycles crashing. Amazing what happens when a tubular tire comes off the rim. I was surprised at how long one rider stayed up - he was okay until the front tire went under his rear wheel.

I saw bits flying around in some of the crashes but couldn't make out what those bits were.

https://www.youtube.com/watch?v=tf17hFikqrQ

Cheers

Track tubulars are paper thin so flats from overheating aren't all that uncommon. My friend who has turned into a total anti-carbon fiber nut sent me a video link to a subject he called "carbon fiber rim exploding under track rider." That isn't what I would have called it. If you look at it closely it looks like a track tandem gets a flat in the final sprint which throws the entire weight of the team unto the front disk which slowly comes apart as the tire peels off.

I showed him that foregoing manufacturing errors that all of the bicycle materials have approximately the same loaded lifespan. That was sort of surprising to me since I have a lot of steel bikes and never had a failure. But I suppose I usually buy them with very little use and they simply don't have that many miles.

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.

Interesting.
Of course Sheldon Brown, that sneaky devil, describes a study
conducted by EFBe (Engineering for Bikes) which is now, I believe, one
of the main elements of the DIN 79100 bicycle-testing standard, which
was published in TOUR magazine of Oct 1997 ( more then 20 years ago)
that demonstrated that two of the three frames that completed the test
with no failures were welded aluminum frames. Two out of three... lets
see, that is about 66.666 %, isn't it?

The Christian Bible has a phrase that seems to apply here (Proverbs
17:28. New International Version)

"Even a fool is thought wise if he keeps silent, and discerning if he
holds his tongue."

cheers,

John B.

Of course anyone with any training would understand that this testing meant nothing. While the test itself was well designed using a single example of each frame yielded no more information that THAT single example.

But then you're the sort of engineer who would build a bridge without actually testing the components of it.

I see... first you condemn a test to failure as it tests only one
example and then you refer to testing bridge components.

Tom, you are a fool. Or do you actually believe that each component of
a bridge is tested to failure... before it is used?

I worked for a company that specialized in contacting with
international oil companies to build and.or maintain oil fields in
remote areas and in doing so we built innumerable bridges and I'm
sorry to inform you that we never tested the components of any of the
bridges... never. And I can assure you that none of the bridges ever
fell down.

I might add, that as we were in business for over 20 years, and as oil
companies were still giving us contacts it is patently obvious that we
knew what we were doing as oil companies don't renew contacts to
companies that build bridges that fall down.

I keep telling you, "It's better to keep your mouth shut and appear
stupid than open it and remove all doubt" and you don't listen.


Indonesia may have some regard for human life and
engineering standards. Not everyone does:

https://am1590theanswer.com/news/nat...10-years-later

Well, the bridge was ~50 years old and had some 300 tons of
construction materials stockpiled on the deck for renovations :-)

The English built an iron bridge in 1781, that is still in use. Or
better yet, the Greeks. They built a bridge ~3,000+ years ago that is
still in use :-)

But you will persist in having things built by the low bidders :-(

cheers,

John B.

On Fri, 28 Dec 2018 20:41:49 -0500, Frank Krygowski
wrote:

On 12/28/2018 5:41 PM, wrote:
On Wednesday, December 26, 2018 at 4:22:08 PM UTC-8, John B. Slocomb wrote:
On Wed, 26 Dec 2018 12:02:58 -0800 (PST), wrote:

On Thursday, November 29, 2018 at 1:25:28 PM UTC-8, Sir Ridesalot wrote:
An interesting video of track bicycles crashing. Amazing what happens when a tubular tire comes off the rim. I was surprised at how long one rider stayed up - he was okay until the front tire went under his rear wheel.

I saw bits flying around in some of the crashes but couldn't make out what those bits were.

https://www.youtube.com/watch?v=tf17hFikqrQ

Cheers

Track tubulars are paper thin so flats from overheating aren't all that uncommon. My friend who has turned into a total anti-carbon fiber nut sent me a video link to a subject he called "carbon fiber rim exploding under track rider." That isn't what I would have called it. If you look at it closely it looks like a track tandem gets a flat in the final sprint which throws the entire weight of the team unto the front disk which slowly comes apart as the tire peels off.

I showed him that foregoing manufacturing errors that all of the bicycle materials have approximately the same loaded lifespan. That was sort of surprising to me since I have a lot of steel bikes and never had a failure. But I suppose I usually buy them with very little use and they simply don't have that many miles.

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.

Interesting.
Of course Sheldon Brown, that sneaky devil, describes a study
conducted by EFBe (Engineering for Bikes) which is now, I believe, one
of the main elements of the DIN 79100 bicycle-testing standard, which
was published in TOUR magazine of Oct 1997 ( more then 20 years ago)
that demonstrated that two of the three frames that completed the test
with no failures were welded aluminum frames. Two out of three... lets
see, that is about 66.666 %, isn't it?

The Christian Bible has a phrase that seems to apply here (Proverbs
17:28. New International Version)

"Even a fool is thought wise if he keeps silent, and discerning if he
holds his tongue."

cheers,

John B.

Of course anyone with any training would understand that this testing meant nothing. While the test itself was well designed using a single example of each frame yielded no more information that THAT single example.

But then you're the sort of engineer who would build a bridge without actually testing the components of it.

?? Tom, did you learn bridge design from this cartoon?
https://www.gocomics.com/calvinandhobbes/1986/11/26

A short history of the engineering trade:
Build it. If it breaks build it again but make it stronger :-)

cheers,

John B.