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program to compute gears, with table



 
 
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  #21  
Old September 9th 17, 02:58 PM posted to rec.bicycles.tech
AMuzi
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Posts: 8,762
Default program to compute gears, with table

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

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


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  #22  
Old September 9th 17, 03:18 PM posted to rec.bicycles.tech
AMuzi
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Posts: 8,762
Default program to compute gears, with table

On 9/8/2017 11:46 PM, Emanuel Berg wrote:
John B. wrote:

"well, we do still have a few 9 speed chains
left".


Anyone feel free to elaborate on this. How and
why should the chain be different with
different cassette/chainring configurations?

And is there a "notation" do describe this?
Usually makes it easier to understand...


Overall width.
4/5 speed systems used very wide chain as you may recall.
To get 8, 9, 10, 11 sprockets inside the 130mm road format
(originally seven speeds) the sprockets are closer and so
the chain is smaller.

http://www.yellowjersey.org/photosfr...t/MANYCHAN.JPG

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #23  
Old September 9th 17, 04:04 PM posted to rec.bicycles.tech
AMuzi
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Posts: 8,762
Default program to compute gears, with table

On 9/9/2017 5:37 AM, Emanuel Berg wrote:
John B. wrote:

The rear sprocket spacing is closer as the
number of cassette cogs goes up, so
narrower chains.

The over all length of the cassette is
limited by the distance between the rear drop
outs as the wider the cassette the more the
hub flange on that side must be offset and
thus the angle of the spokes decreases.


Okay? Is that the reason you simply cannot make
the back fork wider? At some point the spoke
angle will make for a wheel that isn't
strong enough?


People have been predicting doom in that regard for a very
long while. In theory maybe but in practice not yet.


--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #24  
Old September 9th 17, 05:34 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 353
Default program to compute gears, with table

AMuzi wrote:

Overall width. 4/5 speed systems used very
wide chain as you may recall. To get 8, 9,
10, 11 sprockets inside the 130mm road format
(originally seven speeds) the sprockets are
closer and so the chain is smaller.


So could one have like a 3 sprocket casette
with old chainring quality and then use a fat
chain to not have to replace anything save for
perhaps the chain, but even that much
less often?

Or does moving the chain wear down even
wide sprockets?

--
underground experts united
http://user.it.uu.se/~embe8573
  #25  
Old September 9th 17, 05:36 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 353
Default program to compute gears, with table

AMuzi wrote:

Okay? Is that the reason you simply cannot
make the back fork wider? At some point the
spoke angle will make for a wheel that isn't
strong enough?

People have been predicting doom in that
regard for a very long while. In theory maybe
but in practice not yet.


I see, yet another "DANGER!" so the
manufacturer can produce even more incompatible
equipment. Show must go on!

--
underground experts united
http://user.it.uu.se/~embe8573
  #26  
Old September 9th 17, 05:40 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 353
Default program to compute gears, with table

AMuzi wrote:

Overall width. 4/5 speed systems used very
wide chain as you may recall. To get 8, 9,
10, 11 sprockets inside the 130mm road format
(originally seven speeds) the sprockets are
closer and so the chain is smaller.


Is it enough to count the sprockets,
e.g. does an 8 sprocket casette always have the
same width? Or does that vary
between manufacturers?

And surely there aren't different chains for
8, 9, 10, and 11 casettes, i.e. four different
chain sizes?

--
underground experts united
http://user.it.uu.se/~embe8573
  #27  
Old September 9th 17, 06:23 PM posted to rec.bicycles.tech
Sir Ridesalot
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Posts: 3,552
Default program to compute gears, with table

On Saturday, September 9, 2017 at 12:40:29 PM UTC-4, Emanuel Berg wrote:
AMuzi wrote:

Overall width. 4/5 speed systems used very
wide chain as you may recall. To get 8, 9,
10, 11 sprockets inside the 130mm road format
(originally seven speeds) the sprockets are
closer and so the chain is smaller.


Is it enough to count the sprockets,
e.g. does an 8 sprocket casette always have the
same width? Or does that vary
between manufacturers?

And surely there aren't different chains for
8, 9, 10, and 11 casettes, i.e. four different
chain sizes?

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


All you have to do is search the web under bicycle chain widths and you'll seethat 5 speed, 7 speed, 9 speed, 10 speed and 11 speed chains are ALL different widths to cope with the narrower spacings between cogs and also the thinner cogs.

Cheers
  #28  
Old September 9th 17, 06:29 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 353
Default program to compute gears, with table

Sir Ridesalot wrote:

All you have to do is search the web


Anything else you can do for me?

--
underground experts united
http://user.it.uu.se/~embe8573
  #29  
Old September 9th 17, 06:35 PM posted to rec.bicycles.tech
Sir Ridesalot
external usenet poster
 
Posts: 3,552
Default program to compute gears, with table

On Saturday, September 9, 2017 at 1:29:12 PM UTC-4, Emanuel Berg wrote:
Sir Ridesalot wrote:

All you have to do is search the web


Anything else you can do for me?

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


I did! I DID! After "web" I had also answered your qquestion with "...under bicycle chain widths and you'll seethat 5 speed, 7 speed, 9 speed, 10 speed and 11 speed chains are ALL different widths to cope with the narrower spacings between cogs and also the thinner cogs."

Cheers

  #30  
Old September 9th 17, 06:40 PM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 8,762
Default program to compute gears, with table

On 9/9/2017 11:40 AM, Emanuel Berg wrote:
AMuzi wrote:

Overall width. 4/5 speed systems used very
wide chain as you may recall. To get 8, 9,
10, 11 sprockets inside the 130mm road format
(originally seven speeds) the sprockets are
closer and so the chain is smaller.


Is it enough to count the sprockets,
e.g. does an 8 sprocket casette always have the
same width? Or does that vary
between manufacturers?

And surely there aren't different chains for
8, 9, 10, and 11 casettes, i.e. four different
chain sizes?


Surely you jest!
There are variants within each format. Plus 12 speed now.
Four chain models is not a shop inventory - it's nothing.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


 




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