program to compute gears, with table
 

Harris Brown Cyclery has a program

Swedish: "Fram med det"

German: "Her da mit"

Swedish again: "...och fort ska det gå!"

German again: "...aber zackig!"

English: "May I have it, please?"

--
underground experts united
http://user.it.uu.se/~embe8573

program to compute gears, with table
 

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.

--
duane

program to compute gears, with table
 

Duane wrote:

11 speed chains don't last as long as 8 speed
chains, if that's what you mean.

Yeah, that's one thing I could have meant.
And why is that? Just smaller chain,
more fragile?

But I was more thinking in the line of power
transfer or perhaps if there is some
implication to shifting. For example if the
chainrings are still suited for the new chain
size, if you just replace the casette (or rear
wheel) and then replace the chain to fit the
new rear spacing.

Also, speaking of shifting, I have a Crescent
Atto Sport here, the cheaper version, and it
has the 2x8 layout that inspired me to do the
program, the shifters are Shimano microShift,
and I noticed they are kind of heavy to
operate, and I got some very minor but still
pain in my left forearm, is this what you have
or can it be tinkered somehow to require less
force to shift?

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underground experts united
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program to compute gears, with table
 

On 08/09/17 21:59, David Scheidt wrote:
In rec.bicycles.tech Joerg wrote:
:On 2017-09-08 10:52, Emanuel Berg wrote:
: Skip Montanaro wrote:
:
: * Why the 1.0 divisor when computing gear?
:
: As explained, otherwise it'll be integer
: division. But I think that qualifies as a hack
: (not an ugly hack tho) so there is no shame in
: spotting it an "error" :)
:
: * You can skip the radius and use wheel
: (diameter) directly in computing
: the circumference.
:
: Right!
:
: * It never occurred to me to do this in Lisp.
: I always just use an online calculator, like:
:
: http://www.gear-calculator.com/?GR=D...&SL=2.6&UN=KMH
:
: Let's agree there is no need to do it in Lisp.
: Only a desire :)
:

:Why make things complicated? I do such stuff with spreadsheets. That's
:what they were invented for. Part of every office software including
:free ones.

I rewrote his code in common lisp in less time than it takes excel to
start.

Dinosaur. SML is the way to go.

program to compute gears, with table
 

Tosspot wrote:

Part of every office software including free
ones. I rewrote his code in common lisp in
less time than it takes excel to start.

Dinosaur. SML is the way to go.

More like you are the dinosaur! Sure, Excel is
from 1987 and SML (Standard Meta Language) is
from 1990.

But SML is a modern implementation of ML from
way back in 1973! ML is sometimes called
"Lisp with types". But Lisp also have types,
only in a different way.

SML and other modern dialects of ML are today
common at universities and popular with
CS people in general (compiler writers,
language-for-the-sake-of-language guys etc.),
but perhaps CS people with a more engineering
inclination than the purists on Haskell.

--
underground experts united
http://user.it.uu.se/~embe8573

program to compute gears, with table
 

On Mon, 11 Sep 2017 07:19:46 +0200, Emanuel Berg
wrote:

Tosspot wrote:

Part of every office software including free
ones. I rewrote his code in common lisp in
less time than it takes excel to start.

Dinosaur. SML is the way to go.

More like you are the dinosaur! Sure, Excel is
from 1987 and SML (Standard Meta Language) is
from 1990.

But SML is a modern implementation of ML from
way back in 1973! ML is sometimes called
"Lisp with types". But Lisp also have types,
only in a different way.

SML and other modern dialects of ML are today
common at universities and popular with
CS people in general (compiler writers,
language-for-the-sake-of-language guys etc.),
but perhaps CS people with a more engineering
inclination than the purists on Haskell.

Assembler for ever!

Word Star, the first really good word processor application was
written in assembler by a single programmer over a period of about a
month and the program was released in 1978. A "version 2.0" was
released which was copy protected and a financial failure, but the
first real "new" version was version 3, released in 1983.
--
Cheers,

John B.

program to compute gears, with table
 

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!

--
underground experts united
http://user.it.uu.se/~embe8573

program to compute gears, with table
 

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.


--
Cheers,

John B.

program to compute gears, with table
 

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...

--
underground experts united
http://user.it.uu.se/~embe8573

program to compute gears, with table
 

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:

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

--
underground experts united
http://user.it.uu.se/~embe8573