friction shifters linear gear shifts?

[g.daniels]

any hot ideas on how to adjust friction mechanisms to produce linear
shifts at both top and bottom rear cogs?

 

[Sheldon Brown]

g.daniels wrote:

> any hot ideas on how to adjust friction mechanisms to produce linear
> shifts at both top and bottom rear cogs?

no such possibilitude due to constant radius of cable drum vs cosine
error in derailer linkage unless you use an old coil-spring derailer
like a benelux mark viii or vii ofcourse you could 'facture a fricter
with variableradial cable drum

sheldon "dontneed no steenking punctuationor shiftkey-dontcare if
messageis comprehensibible" brown
+------------------------------------------------------+
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| If you only have one, that's how strong you get. |
| -- Mike Shaw |
+------------------------------------------------------+
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Phone 617-244-9772 FAX 617-244-1041
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[G. Huang]

g.daniels wrote:
> any hot ideas on how to adjust friction mechanisms to produce linear
> shifts at both top and bottom rear cogs?

I believe the friction shifter is linear in the sense that the amount of
cable pulled is a linear function of the angular position of the lever.
The derailleur may not linearly translate the cable-pull to the
displacement of the cage, and I don't think that is adjustable.
GH

 

[Benjamin Lewis]

Sheldon Brown wrote:

> g.daniels wrote:
>
>> any hot ideas on how to adjust friction mechanisms to produce linear
>> shifts at both top and bottom rear cogs?
>
> no such possibilitude due to constant radius of cable drum vs cosine
> error in derailer linkage unless you use an old coil-spring derailer like
> a benelux mark viii or vii ofcourse you could 'facture a fricter with
> variableradial cable drum
>
> sheldon "dontneed no steenking punctuationor shiftkey-dontcare if
> messageis comprehensibible" brown

I'm somewhat embarrassed to say it, but I understood you perfectly.

--
Benjamin Lewis

Don't take life so serious, son, it ain't nohow permanent.
-- Walt Kelly

 

[Rick Onanian]

Sheldon g.danielized:
>> sheldon "dontneed no steenking punctuationor shiftkey-dontcare if
>> messageis comprehensibible" brown

<[email protected]> wrote:
>I'm somewhat embarrassed to say it, but I understood you perfectly.

You're well practiced from reading g.danielsese.
--
Rick Onanian

 

[Benjamin Lewis]

Rick Onanian wrote:

> Sheldon g.danielized:
>>> sheldon "dontneed no steenking punctuationor shiftkey-dontcare if
>>> messageis comprehensibible" brown
>
> <[email protected]> wrote:
>> I'm somewhat embarrassed to say it, but I understood you perfectly.
>
> You're well practiced from reading g.danielsese.

It may also be from several readings of _Riddley Walker_ by Russell Hoban.

--
Benjamin Lewis

Gravity is a myth, the Earth sucks.

 

[g.daniels]

right! i cudn't have writ it better.
butbubtut, i examined (loosely put) the problem or at least part of it
on a long straight yesterday into the wind and alone on the wide
mulsanne thus avoiding the SEE ROCK CITY signs and dirt bikers with
friction shifters.
and what i came up with bedies double vision wuza the:

SHADOW GEAR!!
the(ah expletive deleted i furgot to count it's teeth)3 cog down from
the 34-32-shadow gear/28?-24? is a skip running with the small CR
going to the 32 and to the 24 from the 32 unless the cable is turned
pretty tightly.
the 3 cog from the bottom does something likewise but not as often
prefering to thrum instead.
eye guess(whew that's along ways aback there)the linear fucntion is
performed by the large CR and if needing accuracy so as to avoid
physical damage to the pudendal area, scrotum, and ACL, the big CR is
the way togo.
the two 3 cogs on this non-linear setup takes significant effort(s) to
get into even in the spread the wear riding mode but taking the
hairpin flatout mode requires the extra cablescrew twist and the big
CR.
this is the reason or one of the reasons for index shifting on the new
bike?