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Thunked my helmet a fourth time



 
 
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  #21  
Old September 21st 15, 01:19 AM posted to rec.bicycles.misc
John B.[_6_]
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Posts: 2,202
Default Thunked my helmet a fourth time

On Sun, 20 Sep 2015 16:34:38 -0700 (PDT), wrote:

On Sunday, September 13, 2015 at 6:41:45 AM UTC-7, Frank Krygowski wrote:
On 9/12/2015 5:00 PM, Phil W Lee wrote:
John B. considered Sat, 12 Sep 2015 08:54:40
+0700 the perfect time to write:


About 75% of all bicyclists who die each year die of head injuries.

I think you'll find (unless it's very different from the UK, which
seems unlikely given the common mechanism of injury) that it's 75%
that have a brain injury at the time of their death, which may well
have occurred anyway due to other injuries.
Not much point in keeping your head in one piece if you've bled out
anyway. And even a motorcycle helmet won't save your head if a heavy
truck drives over it, or even some much lighter vehicles. So the most
you can do is cite that 75% as an upper bound.


I suspect the origin of the overestimate was a propaganda statement that
"75% of bicyclist fatalities involve a head injury." At least, that's
the way I first saw it expressed years ago. (Sorry, no citation.)

That version may be literally true - as in, the dead cyclist may have
had his abdomen run over by a truck's wheels, and he also got a little
scratch on his head. But the phrasing was obviously intended to trick
the reader into believing that helmets might prevent something like 75%
of fatalities. And other helmet proselytizers missed the subtlety and
went for the straight-out lie.

Similarly, after the infamous Thompson & Rivara paper of 1989 claimed
that helmets prevent 85% of head injuries, another paper used that
number to claim universal helmet use would prevent 85% of American bike
fatalities. And astonishingly, that made it through peer review.
--
- Frank Krygowski


Helmets are designed to do one thing and one thing only. It was designed around the old coaster bike where you were trying to make an emergency stop you would stand up. That put your head about 2 meters above the ground. The helmet was designed not for a collision but for a sideways fall from that standing position.


Wherever did you get that idea?

I grew up in an era when there wasn't anything except coaster brakes
and I never, and I've never seen anyone, stand up to brake with a
coaster brake. And, I might add, I grew up in a rather mountainous
part of New Hampshire where one used the brake a great deal of the
time.

As an aside, the first mention I see to "bicycle helmets" dates back
to the 1880's, while the "coaster brake" seems to have been first made
in 1898.
--
cheers,

John B.

Ads
  #23  
Old October 3rd 15, 09:28 PM posted to rec.bicycles.misc
[email protected]
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Posts: 145
Default Thunked my helmet a fourth time

On Sunday, September 20, 2015 at 5:19:45 PM UTC-7, John B. wrote:
On Sun, 20 Sep 2015 16:34:38 -0700 (PDT), wrote:

On Sunday, September 13, 2015 at 6:41:45 AM UTC-7, Frank Krygowski wrote:
On 9/12/2015 5:00 PM, Phil W Lee wrote:
John B. considered Sat, 12 Sep 2015 08:54:40
+0700 the perfect time to write:


About 75% of all bicyclists who die each year die of head injuries.

I think you'll find (unless it's very different from the UK, which
seems unlikely given the common mechanism of injury) that it's 75%
that have a brain injury at the time of their death, which may well
have occurred anyway due to other injuries.
Not much point in keeping your head in one piece if you've bled out
anyway. And even a motorcycle helmet won't save your head if a heavy
truck drives over it, or even some much lighter vehicles. So the most
you can do is cite that 75% as an upper bound.

I suspect the origin of the overestimate was a propaganda statement that
"75% of bicyclist fatalities involve a head injury." At least, that's
the way I first saw it expressed years ago. (Sorry, no citation.)

That version may be literally true - as in, the dead cyclist may have
had his abdomen run over by a truck's wheels, and he also got a little
scratch on his head. But the phrasing was obviously intended to trick
the reader into believing that helmets might prevent something like 75%
of fatalities. And other helmet proselytizers missed the subtlety and
went for the straight-out lie.

Similarly, after the infamous Thompson & Rivara paper of 1989 claimed
that helmets prevent 85% of head injuries, another paper used that
number to claim universal helmet use would prevent 85% of American bike
fatalities. And astonishingly, that made it through peer review.
--
- Frank Krygowski


Helmets are designed to do one thing and one thing only. It was designed around the old coaster bike where you were trying to make an emergency stop you would stand up. That put your head about 2 meters above the ground. The helmet was designed not for a collision but for a sideways fall from that standing position.


Wherever did you get that idea?

I grew up in an era when there wasn't anything except coaster brakes
and I never, and I've never seen anyone, stand up to brake with a
coaster brake. And, I might add, I grew up in a rather mountainous
part of New Hampshire where one used the brake a great deal of the
time.

As an aside, the first mention I see to "bicycle helmets" dates back
to the 1880's, while the "coaster brake" seems to have been first made
in 1898.


I can't even imagine how you would put a coaster brake on hard without standing on it. Can you explain how a brake that relies on the pressure on a single pedal can possibly be put on in an emergency stop WITHOUT standing on the brake?

You cannot even watch kids riding coaster brake bikes or even BMX bikes with coaster brakes that aren't standing on the pedals for control.
  #24  
Old October 3rd 15, 10:35 PM posted to rec.bicycles.misc
[email protected]
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Posts: 145
Default Thunked my helmet a fourth time

On Tuesday, September 22, 2015 at 1:01:03 PM UTC-7, The Real Bev wrote:
On 09/20/2015 04:04 PM, wrote:

I could go into great detail about helmets since I started learning
about them as the Safety Director of the American Federation of
Motorcyclists about the time Bell started and I had some long
discussions with people at Bell. I am also an engineer and a
scientist. I wrote one of the few peer reviewed papers on bicycle
helmets.


Long ago I had/read a USAF publication about helmet design which had a
lot of useful/interesting information. I recently did a google etc.
search for it and turned up nothing. Did you ever read that?

Helmets are capable of VERY little and at the cost of setting you up
for two other kinds of killer injuries.

I wear one because they are good for one thing - keeping your head
from getting gravel rash in a mild crash. In harder crashes they can
cause severe concussions or broken necks. Funny thing - evolution
didn't design your head like a helmet for a reason.


I remember reading that they were designed to "protect" the head from a
6-foot fall straight down. An unlikely occurrence, I think...

The majority of accidents to adults are the fault of the car. An
approaching driver making a sudden left turn. And a car approaching
from behind, accelerating to pass you and then suddenly turning
right.

The left turn danger is MUCH reduced if you wear bright clothing.
This both makes you much easier to see to the approaching driver plus
it makes it more difficult for the driver to guess your speed making
him think you are faster than he might otherwise think.


I favor as much neon-color as possible -- the guy who hits me is NOT
going to be able to tell the judge he didn't see me.

The "right hook" is impossible to prevent. But you can be aware of
the sounds of a driver about to pull this dumb stunt.


Bev, I remember little about Air Force helmets and I was in the Air Force and had to wear them upon occasion. They had almost no protection of any sort. They had a rather medium strength padding if memory serves and were hard shelled to protect your head from being slapped against the areas around your cockpit seat. Because of the peculiarities of a B52 there was little to no chance that I could survive in case of aircraft damage. So I didn't worry about it. That led to insanities such as crawling to and from the tail gunners position on an 8" wide shelf. On the way back we were under fire and on the way back the bomb bays were open. Imagine leaning two feet to your side while crawling on an 8" shelf and the only way to hold on was to hook two fingers into a slight opening where the fore/aft and latitudinal ribs crossed. Scoot up a couple of inches and repeat until arrival. It would only take 5 minutes.

Bell started out to build helmets for motorcyclists. Very simple calculations using medical data on the strength of the skull and the neck's ability to withstand whiplash set an upper limit on the weight of a helmet.

Later for bicycles this was modified slightly for calculations on the maximum size of a helmet and a person in athletic pursuits would wear. In both cases the size of the helmet came out very closely the same.

BUT --- Since the size of the helmet was limited and the strength of the skull likewise, the material that the padding could be made out of became quite limited.

So they designed the helmet to be capable of APPROXIMATELY a six foot fall onto a hard flat surface with no protrusions.

The motorcycle helmet's hard shell was designed to protect the skull and later the face in a crash in which the head was dragged along the ground. As a person that has gone through a number of helmets while racing I can tell you that the normal fall is in a turn and losing traction and going down. Your head does NOT hit first and the blow is rather small. And the helmet is very effective in this manner.

On the bicycle helmet however, it was designed to take a single fall and not fracture the skull.

Unfortunately they did not consult Mother Nature. The limits of the strength of the skull are not simply the weight of the head and the strength of bone. The strength has actually been part of evolution and the skull is designed to fracture and cushion the brain in that manner before allowing concussions. Concussion is from the accelerative forces tearing the brain away from the skull (most often on the opposite side from the blow) and allowing it to smash into the area of the strike.

A fractured skull is very dangerous but can be survived. Concussion is damage to the brain itself and not only may not be survived but surviving, the brain may become more or less inoperable. This is commonly shown in injuries to boxers or football players who are only using the strength of the human body without the additions of gravity.

But the ability of the helmet to prevent skull fracture enhances the ability of a fall to cause serious concussion. In me it causes intermittent seizures that can totally eliminate any short and long term memory to the point where I don't even remember to eat or drink. It is controlled by twice daily medication which has taken me three years to get used to the side effects of dizziness and the brain damage which makes the forward part of the feet unfeeling and hence balance difficult. But you ALSO have a balance mechanism tied to your hips and so I can ride a bike fine even though I have to walk like a duck to retain my balance.

It happened to me when I was bending over to move the front wheel speedo pickup out a little to stop the ticking. My head was only three feet off of the ground when the front fork fell apart and dropped me on my head. The helmet was completely crushed. The bones on one brow ridge were broken BY THE HELMET. I was unconscious for over five minutes. One eye (or section of the brain) was damaged so that things appear larger in one eye than the other.

The fork I was using was a first generation carbon fiber fork that was incorrectly made so this is a highly unlikely event but demonstrates that a helmet has effectively no ability to protect a cyclist.

There is perhaps one chance in thousands that in a normal street accident that a helmet could actually help you. And more than that, that it can harm you.

What the heck - I'll hope for a help and not a harm since I'm a careful cyclist.

But the truth of the matter is that street accidents are entirely outside of the ability of a helmet to cope with. Most accident involve motor vehicles at speeds of 25 mph or higher. So if someone decides to not wear a helmet don't rag on them because it isn't doing YOU any good to have one.
  #25  
Old October 3rd 15, 10:50 PM posted to rec.bicycles.misc
[email protected]
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Posts: 145
Default Thunked my helmet a fourth time

On Tuesday, September 22, 2015 at 8:05:33 PM UTC-7, John B. wrote:
On Tue, 22 Sep 2015 13:00:59 -0700, The Real Bev
wrote:

On 09/20/2015 04:04 PM, wrote:

I could go into great detail about helmets since I started learning
about them as the Safety Director of the American Federation of
Motorcyclists about the time Bell started and I had some long
discussions with people at Bell. I am also an engineer and a
scientist. I wrote one of the few peer reviewed papers on bicycle
helmets.


Long ago I had/read a USAF publication about helmet design which had a
lot of useful/interesting information. I recently did a google etc.
search for it and turned up nothing. Did you ever read that?


Out of curiosity, what was the U.S.A.F. publication about? The usual
pilot's, or air crew member's, helmet is more a matter of holding all
the things needed in proximity to the head and protection from wind
forces when ejecting, rather than falling off :-)


Originally a helmet was designed to hold your microphone and earphones. These were the old leather helmets. Later because of the violent g-forces on planes newer than the P-40 they developed the plastic helmets to keep you from injuring yourself from your head slapping from side to side against the many protrusions.

I don't know their present design but I do remember them experimenting with the helmet first strapped to your shoulders to keep it rather straight, to a design of the seats headrest shaped to receive the helmet and lock it more or less in place.

The main use is in combat with extreme g-forces so the pressures are mainly side to side and USUALLY accelerative. But Aces used deceleration to great advantage so they must have made some changes for that.

When you are near or above the speed of sound and pull the throttles back it feels like you hit a mountainside. Or so I'm told. I was a bomber grunt.
  #26  
Old October 4th 15, 01:00 AM posted to rec.bicycles.misc
John B.[_6_]
external usenet poster
 
Posts: 2,202
Default Thunked my helmet a fourth time

On Sat, 3 Oct 2015 13:28:36 -0700 (PDT), wrote:

On Sunday, September 20, 2015 at 5:19:45 PM UTC-7, John B. wrote:
On Sun, 20 Sep 2015 16:34:38 -0700 (PDT),
wrote:

On Sunday, September 13, 2015 at 6:41:45 AM UTC-7, Frank Krygowski wrote:
On 9/12/2015 5:00 PM, Phil W Lee wrote:
John B. considered Sat, 12 Sep 2015 08:54:40
+0700 the perfect time to write:


About 75% of all bicyclists who die each year die of head injuries.

I think you'll find (unless it's very different from the UK, which
seems unlikely given the common mechanism of injury) that it's 75%
that have a brain injury at the time of their death, which may well
have occurred anyway due to other injuries.
Not much point in keeping your head in one piece if you've bled out
anyway. And even a motorcycle helmet won't save your head if a heavy
truck drives over it, or even some much lighter vehicles. So the most
you can do is cite that 75% as an upper bound.

I suspect the origin of the overestimate was a propaganda statement that
"75% of bicyclist fatalities involve a head injury." At least, that's
the way I first saw it expressed years ago. (Sorry, no citation.)

That version may be literally true - as in, the dead cyclist may have
had his abdomen run over by a truck's wheels, and he also got a little
scratch on his head. But the phrasing was obviously intended to trick
the reader into believing that helmets might prevent something like 75%
of fatalities. And other helmet proselytizers missed the subtlety and
went for the straight-out lie.

Similarly, after the infamous Thompson & Rivara paper of 1989 claimed
that helmets prevent 85% of head injuries, another paper used that
number to claim universal helmet use would prevent 85% of American bike
fatalities. And astonishingly, that made it through peer review.
--
- Frank Krygowski

Helmets are designed to do one thing and one thing only. It was designed around the old coaster bike where you were trying to make an emergency stop you would stand up. That put your head about 2 meters above the ground. The helmet was designed not for a collision but for a sideways fall from that standing position.


Wherever did you get that idea?

I grew up in an era when there wasn't anything except coaster brakes
and I never, and I've never seen anyone, stand up to brake with a
coaster brake. And, I might add, I grew up in a rather mountainous
part of New Hampshire where one used the brake a great deal of the
time.

As an aside, the first mention I see to "bicycle helmets" dates back
to the 1880's, while the "coaster brake" seems to have been first made
in 1898.


I can't even imagine how you would put a coaster brake on hard without standing on it. Can you explain how a brake that relies on the pressure on a single pedal can possibly be put on in an emergency stop WITHOUT standing on the brake?

You cannot even watch kids riding coaster brake bikes or even BMX bikes with coaster brakes that aren't standing on the pedals for control.


Well, I suspect that it might depend on how well maintained your rear
hub is/was. I can't remember ever having to "stand" on the pedal to
make the bike stop although I do admit that when my Dad bought my 1st,
2nd, 3rd hand first bike the brake didn't work at all until I it.

Largely, I suspect because the brake was on the rear wheel and even a
little force to actuate the brake resulted in a forward weight shift
and the wheel locking.

In fact one of the stunts that the "accomplished" rider used to
demonstrate his skill, dexterity and general superiorly (as well as
showing off to the girls) was to pedal as fast as you could, and just
as you went in front of the girls, lay the bike over and stamp on the
brake. If you were really "good" the bike would make a skidding 180
degree spin as it stopped. Very hard to do standing on one pedal.

From your post it seems likely that you either have never ridden a
coaster brake bike or simply don't know what you are talking about.
--
cheers,

John B.

  #27  
Old November 12th 15, 08:09 AM posted to rec.bicycles.misc
The Real Bev[_2_]
external usenet poster
 
Posts: 40
Default Thunked my helmet a fourth time

On 09/22/2015 08:05 PM, John B. wrote:
On Tue, 22 Sep 2015 13:00:59 -0700, The Real Bev
wrote:

On 09/20/2015 04:04 PM, wrote:

I could go into great detail about helmets since I started learning
about them as the Safety Director of the American Federation of
Motorcyclists about the time Bell started and I had some long
discussions with people at Bell. I am also an engineer and a
scientist. I wrote one of the few peer reviewed papers on bicycle
helmets.


Long ago I had/read a USAF publication about helmet design which had a
lot of useful/interesting information. I recently did a google etc.
search for it and turned up nothing. Did you ever read that?


Out of curiosity, what was the U.S.A.F. publication about? The usual
pilot's, or air crew member's, helmet is more a matter of holding all
the things needed in proximity to the head and protection from wind
forces when ejecting, rather than falling off :-)


It dealt with structure of the helmet, how different parts of the head
needed to be protected, appropriate weight, etc. I think there were
equations. It was written during the 40s or early 50s when things were
different. A thing I remember especially is that hair alone provides
significant protection from abrasion.

--
Cheers, Bev
++++++++++++++++++++++++++++++++++++++++++++++
666F -- the oven temperature for roast beast.
  #28  
Old November 12th 15, 08:22 AM posted to rec.bicycles.misc
The Real Bev[_2_]
external usenet poster
 
Posts: 40
Default Thunked my helmet a fourth time

On 10/03/2015 02:50 PM, wrote:
On Tuesday, September 22, 2015 at 8:05:33 PM UTC-7, John B. wrote:
On Tue, 22 Sep 2015 13:00:59 -0700, The Real Bev
wrote:

On 09/20/2015 04:04 PM,
wrote:

I could go into great detail about helmets since I started
learning about them as the Safety Director of the American
Federation of Motorcyclists about the time Bell started and I
had some long discussions with people at Bell. I am also an
engineer and a scientist. I wrote one of the few peer reviewed
papers on bicycle helmets.

Long ago I had/read a USAF publication about helmet design which
had a lot of useful/interesting information. I recently did a
google etc. search for it and turned up nothing. Did you ever
read that?


Out of curiosity, what was the U.S.A.F. publication about? The
usual pilot's, or air crew member's, helmet is more a matter of
holding all the things needed in proximity to the head and
protection from wind forces when ejecting, rather than falling off
:-)


Originally a helmet was designed to hold your microphone and
earphones. These were the old leather helmets.


Last time I looked at a J.C. Whitney catalog they were still selling
those. They were modeled by what looked like a chimp...

Later because of the
violent g-forces on planes newer than the P-40 they developed the
plastic helmets to keep you from injuring yourself from your head
slapping from side to side against the many protrusions.

I don't know their present design but I do remember them
experimenting with the helmet first strapped to your shoulders to
keep it rather straight, to a design of the seats headrest shaped to
receive the helmet and lock it more or less in place.

The main use is in combat with extreme g-forces so the pressures are
mainly side to side and USUALLY accelerative. But Aces used
deceleration to great advantage so they must have made some changes
for that.

When you are near or above the speed of sound and pull the throttles
back it feels like you hit a mountainside. Or so I'm told. I was a
bomber grunt.


Thanks for that.

A former boss flew transports and loved to tell the occasional female
passenger about the relief tube AFTER plying her with as much coffee as
she could hold.

--
Cheers, Bev
++++++++++++++++++++++++++++++++++++++
666F -- the oven temperature for roast beast.
  #29  
Old November 12th 15, 01:40 PM posted to rec.bicycles.misc
Andrew Chaplin
external usenet poster
 
Posts: 206
Default Thunked my helmet a fourth time

The Real Bev wrote in news:[email protected]
email.me:

A thing I remember especially is that hair alone provides
significant protection from abrasion.


Your mileage may vary--wildly!
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO
(If you're going to e-mail me, you'll have to get "yourfinger." out.)
  #30  
Old November 12th 15, 09:08 PM posted to rec.bicycles.misc
The Real Bev[_2_]
external usenet poster
 
Posts: 40
Default Thunked my helmet a fourth time

On 11/12/2015 04:40 AM, Andrew Chaplin wrote:
The Real Bev wrote in news:[email protected]
email.me:

A thing I remember especially is that hair alone provides
significant protection from abrasion.


Your mileage may vary--wildly!


Indeed. But surprises happen sometimes.

When I crashed on my motorcycle and slid along the ground the parts of
my body protected by flimsy cloth were fine; my shirt rode up and
exposed half a square foot of abdomen skin, which eventually formed a
scab 1/4 inch thick in places and cracked AND HURT where I bent. I
eventually got in the tub and soaked it off.

I figure hair is about the same. Still, I wear a helmet. Not when I
ski, though.

--
Cheers, Bev
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Do not try to solve all life's problems at once -- learn to
dread each day as it comes. -- Donald Kaul
 




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