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  #21  
Old December 16th 18, 12:26 AM posted to rec.bicycles.tech
John B. Slocomb
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Posts: 805
Default casette shifting, again

On Sat, 15 Dec 2018 19:30:51 +0100, Emanuel Berg
wrote:

AMuzi wrote:

For braking, pad size is a minor factor.
It's all swept area, CF and leverage.
You're right that linkage is efficient but
the leverage is minimal and rubber on chromed
steel has a low CF, made worse by dried
hard pads.


OK, so now it got complicated...

Swept area, should that be big or small for the
brake to be efficient? Small, right? As in disc
brakes where say a single degree of braking on
the small disc translates to a much larger
distance on the big wheel?

Or are disc brakes more efficient because of
material interaction and other technology
improvements alone?

And if the linkage on rod brakes is efficient,
how can leverage be minimal unless there is
something wrong with the levers, and they seem
pretty straightforward to me? Or is it the
shackle that is pulled onto the rim, as opposed
to squeezed into/around it, which is
more efficient?

Also, CF, is that some material
interaction property?


CF might indicate Carbon Fiber but I believe in this case it probably
means Coefficient of Friction :-)

cheers,

John B.


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  #22  
Old December 16th 18, 12:29 AM posted to rec.bicycles.tech
John B. Slocomb
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Posts: 805
Default casette shifting, again

On Sat, 15 Dec 2018 22:04:51 +0100, Emanuel Berg
wrote:

Frank Krygowski wrote:

Emanuel, with all due respect, you should
spend the winter reading a physics book or
two. Or three. Skip the parts on electricity,
atomic physics, etc. Concentrate on forces,
motion, work, energy etc. - the parts that
apply to bicycles. [...]


Blah blah blah, you have told me this at least
a dozen times by now. Probably because it is
easier to be didactic/demeaning than to
actually answer the questions.


Actually answering questions is rather difficult when the recipient
has insufficient knowledge to understand the answer.

cheers,

John B.


  #23  
Old December 16th 18, 12:36 AM posted to rec.bicycles.tech
Ralph Barone[_4_]
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Posts: 853
Default casette shifting, again

Emanuel Berg wrote:
AMuzi wrote:

Blah blah blah, you have told me this at
least a dozen times by now. Probably because
it is easier to be didactic/demeaning than
to actually answer the questions.

Sincerely, Frank's advice is excellent.
Visit a used book store and find a basic
physics textbook. It's well worth a few Krona
and a few hours of your time, if only to
posit questions here!


I spent 6 years, 7 months, and 12 days at the
university. My degree project [1] is 153 pages.
I solved the same problem five other guys did
at two North-American universities. I don't
have to prove to anyone I can read and
understand whatever I put my mind to.

In fact, this has nothing to do with any of
this. This is the bike culture which for
whatever insane reason is snobbish
beyond belief.

You can all try this out for yourself.
Install Emacs, use it until you run into
a problem, then go to gnu.emacs.help and ask
about it. If you get the answer "you are not
using the terminology correctly, go read
a book, then come back" please show it to me,
as, in all my years in computing, I've never
ever seen that.

[1] http://user.it.uu.se/~embe8573/hs-li...ort/report.pdf


I thought that the phrase RTFM came from the computer culture, and not bike
culture. But seriously, if you went on an emacs group and said "I'm having
trouble trying to use the doomahickie thingamajig to make my letters all
angularinated", they'd probably tell you to RTFM and learn the language
before posting.

  #24  
Old December 16th 18, 12:36 AM posted to rec.bicycles.tech
Ralph Barone[_4_]
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Posts: 853
Default casette shifting, again

Emanuel Berg wrote:
Frank Krygowski wrote:

Emanuel, with all due respect, you should
spend the winter reading a physics book or
two. Or three. Skip the parts on electricity,
atomic physics, etc. Concentrate on forces,
motion, work, energy etc. - the parts that
apply to bicycles. [...]


Blah blah blah, you have told me this at least
a dozen times by now. Probably because it is
easier to be didactic/demeaning than to
actually answer the questions.


Frank continues to tell you to read a book because many of us don't answer
your questions because due to your use of non-standard language, we can't
understand your questions.

  #25  
Old December 16th 18, 12:42 AM posted to rec.bicycles.tech
John B. Slocomb
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Posts: 805
Default casette shifting, again

On Sat, 15 Dec 2018 23:01:48 +0100, Emanuel Berg
wrote:

AMuzi wrote:

Blah blah blah, you have told me this at
least a dozen times by now. Probably because
it is easier to be didactic/demeaning than
to actually answer the questions.

Sincerely, Frank's advice is excellent.
Visit a used book store and find a basic
physics textbook. It's well worth a few Krona
and a few hours of your time, if only to
posit questions here!


I spent 6 years, 7 months, and 12 days at the
university. My degree project [1] is 153 pages.
I solved the same problem five other guys did
at two North-American universities. I don't
have to prove to anyone I can read and
understand whatever I put my mind to.


That is a silly answer. The fact that you spent more then six years at
a school doesn't mean that you know everything. In fact that is quite
evident in your questions about bicycles posted here.


In fact, this has nothing to do with any of
this. This is the bike culture which for
whatever insane reason is snobbish
beyond belief.


Hardly snobbish. the fact is that you don't understand enough about
bicycles to even use the proper nomenclature for the various parts,
never mind understanding how they work. Rather like me coming to your
country and then being amazed that the people I talk with don't
understand what I say.

You can all try this out for yourself.
Install Emacs, use it until you run into
a problem, then go to gnu.emacs.help and ask
about it. If you get the answer "you are not
using the terminology correctly, go read
a book, then come back" please show it to me,
as, in all my years in computing, I've never
ever seen that.


Why in the world would anyone want to use Emacs, (by the way the
proper name is "GNU Emacs") an application that is 40 years old. Yes,
I know that it can do many strange and wondrous things but when you
get right down to it, it is hardly the weapon of choice for writing a
book, posting to USENET or keeping one's shopping list current.




[1] http://user.it.uu.se/~embe8573/hs-li...ort/report.pdf


cheers,

John B.


  #26  
Old December 16th 18, 12:42 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default casette shifting, again

On 12/15/2018 5:01 PM, Emanuel Berg wrote:
AMuzi wrote:

Blah blah blah, you have told me this at
least a dozen times by now. Probably because
it is easier to be didactic/demeaning than
to actually answer the questions.

Sincerely, Frank's advice is excellent.
Visit a used book store and find a basic
physics textbook. It's well worth a few Krona
and a few hours of your time, if only to
posit questions here!


I spent 6 years, 7 months, and 12 days at the
university. My degree project [1] is 153 pages.
I solved the same problem five other guys did
at two North-American universities. I don't
have to prove to anyone I can read and
understand whatever I put my mind to.

In fact, this has nothing to do with any of
this. This is the bike culture which for
whatever insane reason is snobbish
beyond belief.


I'm not trying to be snobbish. If you ask questions properly, we can
answer them.

Example: You asked "Swept area, should that be big or small for the
brake to be efficient?" But in a technical sense, the very purpose of a
brake is to be completely inefficient - that is, to throw away energy.

So what are you asking? Are you referring to lots of braking force for
little input force? Are you referring to little lost motion in the
actuating mechanism? Is it something else? I honestly can't tell.

I don't doubt that you may be brilliant at computers. But not everyone
is a polymath. As an example, one of my colleagues at the university has
a PhD in electronics with many publications in digital systems, robotic
dynamics and stability, etc. However, he had to bring his bike in to
school to have me adjust his brakes. Again, not everyone is a polymath.

And many of the questions you have asked here are extremely basic. If I
didn't already know, I wouldn't ask an international discussion group
what "swept area" of a brake means. I'd google it.
https://www.miataturbo.net/attachmen..._area_calc.png

--
- Frank Krygowski
  #27  
Old December 16th 18, 12:52 AM posted to rec.bicycles.tech
John B. Slocomb
external usenet poster
 
Posts: 805
Default casette shifting, again

On Sat, 15 Dec 2018 15:59:21 -0600, AMuzi wrote:

On 12/15/2018 3:04 PM, Emanuel Berg wrote:
Frank Krygowski wrote:

Emanuel, with all due respect, you should
spend the winter reading a physics book or
two. Or three. Skip the parts on electricity,
atomic physics, etc. Concentrate on forces,
motion, work, energy etc. - the parts that
apply to bicycles. [...]


Blah blah blah, you have told me this at least
a dozen times by now. Probably because it is
easier to be didactic/demeaning than to
actually answer the questions.


more.

I left school without having slept through even one physics
class. My reference work here is a 1955 high school textbook
for $1 (9 Kr). I don't know all of even that, but I
understand the world well enough to know that this headline
last week:

https://www.dailymail.co.uk/sciencet...soon-2022.html

was completely ridiculous. The chamber pressures are in the
same range, but not power, not even within a magnitude*!
Power is work over time. Without some grasp of the actual
world, you would not have laughed aloud when reading the
headline, etc.

*A typical 120mm tank round is 7.5 kilos of depleted uranium
moving at 1700 m/s. The new 6.8 rifle typically moves 7.5
grams at 850 m/s. That's why you need basic physics.



Interesting. First we argue that the old .30 cal was too big and heavy
so the 5.6 being lighter and faster is better and now we are saying
that the 6.8, although larger and heavier, is better. At this rate we
will be back to the 7.62mm :-)

What's next? A return to the 14.7mm?

cheers,

John B.


  #28  
Old December 16th 18, 01:20 AM posted to rec.bicycles.tech
JBeattie
external usenet poster
 
Posts: 5,870
Default casette shifting, again

On Saturday, December 15, 2018 at 1:59:24 PM UTC-8, AMuzi wrote:
On 12/15/2018 3:04 PM, Emanuel Berg wrote:
Frank Krygowski wrote:

Emanuel, with all due respect, you should
spend the winter reading a physics book or
two. Or three. Skip the parts on electricity,
atomic physics, etc. Concentrate on forces,
motion, work, energy etc. - the parts that
apply to bicycles. [...]


Blah blah blah, you have told me this at least
a dozen times by now. Probably because it is
easier to be didactic/demeaning than to
actually answer the questions.


more.

I left school without having slept through even one physics
class. My reference work here is a 1955 high school textbook
for $1 (9 Kr). I don't know all of even that, but I
understand the world well enough to know that this headline
last week:

https://www.dailymail.co.uk/sciencet...soon-2022.html

was completely ridiculous. The chamber pressures are in the
same range, but not power, not even within a magnitude*!
Power is work over time. Without some grasp of the actual
world, you would not have laughed aloud when reading the
headline, etc.

*A typical 120mm tank round is 7.5 kilos of depleted uranium
moving at 1700 m/s. The new 6.8 rifle typically moves 7.5
grams at 850 m/s. That's why you need basic physics.


BTW, here's an interesting case that crossed my desk: https://www.bendbulletin.com/localst...killed-in-tank https://www.oregonlive.com/pacific-n...explosion.html Interesting object lesson for re-loaders. I'm representing a party on a collateral insurance issue. I've represented a couple big gun makers in over-pressure cases. Reloads. Too much powder or the wrong powder can blow-up guns large and small.

-- Jay Beattie.







  #29  
Old December 16th 18, 01:53 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default casette shifting, again

On Sat, 15 Dec 2018 15:59:21 -0600, AMuzi wrote:

I don't know all of even that, but I
understand the world well enough to know that this headline
last week:

https://www.dailymail.co.uk/sciencet...soon-2022.html

was completely ridiculous. The chamber pressures are in the
same range, but not power, not even within a magnitude*!
Power is work over time. Without some grasp of the actual
world, you would not have laughed aloud when reading the
headline, etc.

*A typical 120mm tank round is 7.5 kilos of depleted uranium
moving at 1700 m/s. The new 6.8 rifle typically moves 7.5
grams at 850 m/s. That's why you need basic physics.


It might be correct if they care comparing the 6.8mm ammunition with
the typical shaped charge tank rounds at the maximum effective range
of the tank round. Tank rounds intentionally fly at low velocities so
that the round remains intact on impact for a sufficiently long time
for the Munroe Effect to work. I'm too lazy to run the numbers, but
my guess(tm) is that the delivered energy of a slow tank round might
be approximately the same as the much higher velocity 6.8mm round.
The army hasn't disclosed the exact cartridge that will be used in the
new automatic rifle, but it looks like the muzzle energy will be about
2,100 joules with a 16 inch (410mm) barrel. At identical ranges, the
6.8mm bullet will still be traveling quite fast, while the tank round
will have slowed considerably.

"6.8mm Remington SPC"
https://en.wikipedia.org/wiki/6.8mm_Remington_SPC

"High-explosive anti-tank warhead"
https://en.wikipedia.org/wiki/High-explosive_anti-tank_warhead

"Shaped Charge"
https://en.wikipedia.org/wiki/Shaped_charge

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #30  
Old December 16th 18, 02:04 AM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 4,018
Default casette shifting, again

On Sun, 16 Dec 2018 06:26:08 +0700, John B. Slocomb
wrote:

CF might indicate Carbon Fiber but I believe in this case it probably
means Coefficient of Friction :-)


It Mexico, CF are the labels of the water faucets on a kitchen or
bathroom sinks:
C = Caliente (hot)
F = Frio (cold)

Also in Italian:
C = Caldo (warm)
F = Freddo (cold)

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 




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