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#61
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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
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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
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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
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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
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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
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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
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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
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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 |
#70
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program to compute gears, with table
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