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program to compute gears, with table



 
 
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  #61  
Old September 11th 17, 04:23 PM posted to rec.bicycles.tech
[email protected]
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Posts: 3,345
Default program to compute gears, with table

On Sunday, September 10, 2017 at 3:23:59 PM UTC-7, Duane wrote:
Emanuel Berg wrote:
The spacing between the cogs grows narrower
with growing numbers of gears


Are the sprockets always the same width, only
spacing grows narrower?

and since they have pick-ups to assist
shifting you have to make the chains narrower
to keep them from hopping gears all the time.


Does it impact anything else in the cycling
experience/performance to have
a narrower chain?


11 speed chains don't last as long as 8 speed chains, if that's what you
mean. Performance wise there are too many differences between my 11 speed
and the last 8 speed that I had.


That gear computer was for an eight speed. With a compact cranks and a 12-28 you can see that most of the gears have 10% spread between gears. There is no reason to have closer gearing unless you're racing.

So all you end up with is a set-up for which you need to shift multiple times rather than once to obtain normal performance. And a lot higher cost and faster wear.

This is what the point is isn't it? WHY have components designed to help only the highest performance professional racers other than to pretend to have that sort of performance yourself?

Yesterday I rode on a 35 mile ride. On the way out into a headwind I averaged a little less than 14 mph. I had a cup of coffee while in the city square the worst band I ever heard was making awful noises. When I was in a band if we had played that badly on our first try in a rehearsal we would have quit.

On the way back the wind had reversed and I had a hard time maintaining 12 mph for most of the way. By the time I got home I was exhausted. Do you think that I could improve my performance with an 11 or 12 speed?

I know my limits and it isn't playing as if I was Chris Froome.
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  #62  
Old September 11th 17, 04:34 PM posted to rec.bicycles.tech
[email protected]
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Posts: 3,345
Default program to compute gears, with table

On Monday, September 11, 2017 at 2:54:32 AM UTC-7, John B. wrote:
On Mon, 11 Sep 2017 08:34:20 +0200, Emanuel Berg
wrote:

John B. wrote:

Word Star, the first really good word
processor application was written in
assembler by a single programmer over
a period of about a month


Straight long ear!


Sometime in 1980 Epson wanted to license the software to run on their
PX-8 that used a built in LCD display. The application would have to
run from 48Kb of ROM.

They rehired the Programmer, John Barnaby, who had earlier left the
company, at a salary of $100 an hour (1980 dollars, today $297 ). The
project was completed in two weeks, whereupon Barnaby left the company
again.


It was normal for a job to last the length of a single project. I've held so many positions it isn't funny. My longest period of employment at one company was five years but it really was three years in one company and another two years at a spin-off.
  #63  
Old September 11th 17, 04:39 PM posted to rec.bicycles.tech
[email protected]
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Posts: 3,345
Default program to compute gears, with table

On Monday, September 11, 2017 at 7:00:44 AM UTC-7, Emanuel Berg wrote:
John B. wrote:

Sometime in 1980 Epson wanted to license the
software to run on their PX-8 that used
a built in LCD display. The application would
have to run from 48Kb of ROM.

They rehired the Programmer, John Barnaby,
who had earlier left the company, at a salary
of $100 an hour (1980 dollars, today $297 ).
The project was completed in two weeks,
whereupon Barnaby left the company again.


Assembler isn't really a programming language
in the modern sense, it is more like you say
exactly what the computer should do at a very
low level, down to manually moving data in and
out of CPU registers, just to do for example
basic arithmetics!

It is sometimes used today in combination with
a high-level language (like C) to provide
immediate access to CPU hardware on top
of that.

Today, using a high-level language like
C doesn't really put you at
a speed-disadvantage compared to using
assembler, because the compiler will perform
all sorts of optimizations. So if the
programmer writes sound code and picks
a sound implementation, any hacks left unturned
to get that extra juice can be left to the
compiler to optimize.

Perhaps John Barnaby could do it by moving
individual data items back and forth but for
mere mortals it is an open question if any
performance benefits will follow. Not to
mention (or I will mention it) it will take
some 10 or 100 times the longer to write.

Here is some assembler I wrote some 10 years
ago:


There are assembly programmers still but they sort of write themselves libraries of functions. Then they cross connect these functions. I looked at it but really I could program much smaller and tighter code in C. I could also write in assembly language as well but I write all programs from scratch in that case so you could get a slight increase in speed but not much over a good C compiler.
  #64  
Old September 12th 17, 03:01 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default program to compute gears, with table

On 9/9/2017 4:01 PM, AMuzi wrote:
On 9/9/2017 2:50 PM, Emanuel Berg wrote:
AMuzi wrote:

No jesting! In the shop I go to regularly
there are only two chains, both Shimano, one
is fat (1s) and one is for casettes. The one
for casettes, the "Shimano CN-HG40", is for
6, 7, and 8 sprocket casettes.


No, it is not.


They say it is:

Â*Â*Â*Â* För 6-, 7- och 8-delade kransar. [1]

Might be incorrect, of course.

[1] http://www.clasohlson.com/se/Cykelke...N-HG40/34-8914


The guy who only stocks one model chain knows a lot more than the guy
who made it?

http://bike.shimano.com/content/saus...s/cn-hg40.html


Shifts for crap on a six speed system. Six changers want classic chain
with rivets sticking out the side, especially the fronts.


"Shifts for crap" may vary with the design of the gear train, and the
expectations of the user.

My favorite bike is still my ancient Cannondale touring bike. Five,
count 'em, five rear cogs, and friction shifting.

I bought a bunch of (Sachs?) 8 speed chains on sale, and I think they
shift fine. A big factor is probably the half step (plus granny)
chainring setup. I suppose anything can shift smoothly over a five
tooth chainring difference. And with friction shifting, one may be able
to coax shifts that an index system would find difficult.

BTW, I parenthesize the granny because it gets used only on loaded
tours. And I'm doing less and less of that. Maybe the shift out of the
granny is more difficult than it was with protruding pins; I don't remember.

--
- Frank Krygowski
  #65  
Old September 12th 17, 03:18 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default program to compute gears, with table

On 9/11/2017 5:54 AM, John B. wrote:
On Mon, 11 Sep 2017 08:34:20 +0200, Emanuel Berg
wrote:

John B. wrote:

Word Star, the first really good word
processor application was written in
assembler by a single programmer over
a period of about a month


Straight long ear!


Sometime in 1980 Epson wanted to license the software to run on their
PX-8 that used a built in LCD display. The application would have to
run from 48Kb of ROM.

They rehired the Programmer, John Barnaby, who had earlier left the
company, at a salary of $100 an hour (1980 dollars, today $297 ). The
project was completed in two weeks, whereupon Barnaby left the company
again.


Wow. If someone were paying me $300 per hour to do a job only I could
do, I'd probably take longer than two weeks to do it. ;-)


--
- Frank Krygowski
  #66  
Old September 12th 17, 03:53 AM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 5,697
Default program to compute gears, with table

On Mon, 11 Sep 2017 15:47:59 +0200, Emanuel Berg
wrote:

AMuzi wrote:

The guy who only stocks one model chain knows
a lot more than the guy who made it?

http://bike.shimano.com/content/saus...s/cn-hg40.html

Shifts for crap on a six speed system.
Six changers want classic chain with rivets
sticking out the side, especially the fronts.


Today I went to a bike repair shop (not the
general-purpose store previously mentioned that
"only stocks" the Shimano 1S and 6/7/8 chain
models), and I asked for a 1S chain.

The guy said he had two, one ordinary and
one SS. I asked if the chain really does rust
if you use the bike, and he confirmed it
didn't, so I got the "SC4/0 Steel Roller Chain"
which is 114L 1/2" x 1/8" Made in Taiwan.

I asked about casette chains for specific
numbers of sprockets and he said, without me
mentioning it, one model for 6/7/8, one for 9,
one for 10, and one for 11, with no mention
of 12.

So it would seem he is in agreement with the
Shimano CN-HG40 6/7/8 specification previously
under fire.

Of course, I never tried that on a 6, so this
is just what he said. The plot thickens...


I don't think so. On one hand you are reciting what the specifications
are telling you and on the other hand it is a bloke with years and
years of experience in the business is telling you.
--
Cheers,

John B.

  #67  
Old September 12th 17, 04:05 AM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 5,697
Default program to compute gears, with table

On Mon, 11 Sep 2017 16:00:39 +0200, Emanuel Berg
wrote:

John B. wrote:

Sometime in 1980 Epson wanted to license the
software to run on their PX-8 that used
a built in LCD display. The application would
have to run from 48Kb of ROM.

They rehired the Programmer, John Barnaby,
who had earlier left the company, at a salary
of $100 an hour (1980 dollars, today $297 ).
The project was completed in two weeks,
whereupon Barnaby left the company again.


Assembler isn't really a programming language
in the modern sense, it is more like you say
exactly what the computer should do at a very
low level, down to manually moving data in and
out of CPU registers, just to do for example
basic arithmetics!

It is sometimes used today in combination with
a high-level language (like C) to provide
immediate access to CPU hardware on top
of that.

Today, using a high-level language like
C doesn't really put you at
a speed-disadvantage compared to using
assembler, because the compiler will perform
all sorts of optimizations. So if the
programmer writes sound code and picks
a sound implementation, any hacks left unturned
to get that extra juice can be left to the
compiler to optimize.


That isn't true at all. I have definitely improved the speed of a C
program by using an assembler language sub routines and even had two C
compilers that would compile the same program into two different sizes
that performed the same "test" program at two different speeds.

And I remember a "payroll program" that we developed in Pascal that
ran so slowly that we had to rewrite nearly all the in/out stuff in
assembler.

You want to go back to writing code for a single core CPU screaming
along at 1 Mhz :-)



Perhaps John Barnaby could do it by moving
individual data items back and forth but for
mere mortals it is an open question if any
performance benefits will follow. Not to
mention (or I will mention it) it will take
some 10 or 100 times the longer to write.

Here is some assembler I wrote some 10 years
ago:

http://user.it.uu.se/~embe8573/os/asm.S

--
Cheers,

John B.

  #68  
Old September 12th 17, 04:10 AM posted to rec.bicycles.tech
Sir Ridesalot
external usenet poster
 
Posts: 5,270
Default program to compute gears, with table

On Monday, September 11, 2017 at 10:53:52 PM UTC-4, John B. wrote:
On Mon, 11 Sep 2017 15:47:59 +0200, Emanuel Berg
wrote:

AMuzi wrote:

The guy who only stocks one model chain knows
a lot more than the guy who made it?

http://bike.shimano.com/content/saus...s/cn-hg40.html

Shifts for crap on a six speed system.
Six changers want classic chain with rivets
sticking out the side, especially the fronts.


Today I went to a bike repair shop (not the
general-purpose store previously mentioned that
"only stocks" the Shimano 1S and 6/7/8 chain
models), and I asked for a 1S chain.

The guy said he had two, one ordinary and
one SS. I asked if the chain really does rust
if you use the bike, and he confirmed it
didn't, so I got the "SC4/0 Steel Roller Chain"
which is 114L 1/2" x 1/8" Made in Taiwan.

I asked about casette chains for specific
numbers of sprockets and he said, without me
mentioning it, one model for 6/7/8, one for 9,
one for 10, and one for 11, with no mention
of 12.

So it would seem he is in agreement with the
Shimano CN-HG40 6/7/8 specification previously
under fire.

Of course, I never tried that on a 6, so this
is just what he said. The plot thickens...


I don't think so. On one hand you are reciting what the specifications
are telling you and on the other hand it is a bloke with years and
years of experience in the business is telling you.
--
Cheers,

John B.


Reading Berg's posts makes me think that a lot of times he's trolling. Many times he asks a question then disagrees with what those experts like Andrew who know the RIGHT answer tell him.

Cheers
  #69  
Old September 12th 17, 04:12 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default program to compute gears, with table

On 9/10/2017 1:21 AM, John B. wrote:
On Sat, 09 Sep 2017 08:58:17 -0500, AMuzi wrote:

On 9/8/2017 4:23 PM, wrote:
On Friday, September 8, 2017 at 10:45:07 AM UTC-7, Emanuel Berg wrote:
Graham wrote:

So if your definition of gear is roll out in
mm then it looks close. Do not forget to
include the tyre.

Right, perhaps I should change "gear" into
"roll out" if that's the agreed-upon term.
Perhaps I should even make it print the
formulae first thing.

And I'll include the tyre. Excellent

There's always a slight error this way. The radius of a tire and hence it's circumference changes slightly with pressure and/or weight of the rider.


The ancient and traditional method from race-rules gear
limits to computer input is a rollout.
Ride over a spot of paint and measure between marks. In
theory it's 2R*3.14159. In practice it is not. As you note,
rider weight, inflation etc have some bearing on this


Disregarding "gear inches" I found a sequel to the Freakonomics book
called "SuperFreakonomics" It gets into the economics of street
prostitution early on in the book :-)


Yes, that was interesting too. But she wasn't a street prostitute. She
was a high-priced call girl. With a degree in economics, as I recall!


--
- Frank Krygowski
  #70  
Old September 12th 17, 04:17 AM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 5,697
Default program to compute gears, with table

On Mon, 11 Sep 2017 08:39:26 -0700 (PDT), wrote:

On Monday, September 11, 2017 at 7:00:44 AM UTC-7, Emanuel Berg wrote:
John B. wrote:

Sometime in 1980 Epson wanted to license the
software to run on their PX-8 that used
a built in LCD display. The application would
have to run from 48Kb of ROM.

They rehired the Programmer, John Barnaby,
who had earlier left the company, at a salary
of $100 an hour (1980 dollars, today $297 ).
The project was completed in two weeks,
whereupon Barnaby left the company again.


Assembler isn't really a programming language
in the modern sense, it is more like you say
exactly what the computer should do at a very
low level, down to manually moving data in and
out of CPU registers, just to do for example
basic arithmetics!

It is sometimes used today in combination with
a high-level language (like C) to provide
immediate access to CPU hardware on top
of that.

Today, using a high-level language like
C doesn't really put you at
a speed-disadvantage compared to using
assembler, because the compiler will perform
all sorts of optimizations. So if the
programmer writes sound code and picks
a sound implementation, any hacks left unturned
to get that extra juice can be left to the
compiler to optimize.

Perhaps John Barnaby could do it by moving
individual data items back and forth but for
mere mortals it is an open question if any
performance benefits will follow. Not to
mention (or I will mention it) it will take
some 10 or 100 times the longer to write.

Here is some assembler I wrote some 10 years
ago:


There are assembly programmers still but they sort of write themselves libraries of functions. Then they cross connect these functions. I looked at it but really I could program much smaller and tighter code in C. I could also write in assembly language as well but I write all programs from scratch in that case so you could get a slight increase in speed but not much over a good C compiler.


Yes usually a library of functions... just like C :-)
When you write
main()
{
print("Hello, World\n")
}

it simply calls the function "print" which may be a C function or
could be a pre compiled assembler function.
--
Cheers,

John B.

 




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