Simplex Multiplicator - does it help?

[still just me]

I know SImplex used to recommend these for their bar ends. Did it make
much difference? It looks like the amount of leverage gained would be
minimal and offset by the increase in "play" introduced by having
another mechanism in what would otherwise be a single cable.

But, I've never used one. Anyone have experience with one first hand,
maybe before and after?

Thanks,

[philcycles]

Gary Jacobson wrote:
> My understanding was that these things were primarily for tandems but used
> on singles too when cables stretched more than they do today.
>
> I asked a similar question a while back as I have some NOS Simplex shifters,
> etc. Seem to remember that Sheldon Brown referenced them in his website
> somewhere too.
>
> Gary Jacobson
> Rosendale, NY
>
>
> M-gineering" <ikmotgeenspam@m-gineering.nl> wrote in message
> news:fhq0g0$6vj$1@localhost.localdomain...
> > still just me wrote:
> >> I know SImplex used to recommend these for their bar ends. Did it make
> >> much difference? It looks like the amount of leverage gained would be
> >> minimal and offset by the increase in "play" introduced by having
> >> another mechanism in what would otherwise be a single cable. But, I've
> >> never used one. Anyone have experience with one first hand,
> >> maybe before and after?
> >
> > Had one quite a while ago, left it out later, didn't seem to make any
> > difference
> >

It's a demultiplicator. it's aim-so very French-was to decrease cable
pull at the derailleur, thereby increasing "feel" at the lever, or so
the ad I saw for it said. Nothing to do with streach or tandems or
anything ratiional. I had one-even made a braze-on for it-with Simplex
barends and it would pull a 7 speed freewheel just fine. I didn't
notice any increased feel but then, I'm not French. I still have one
floating around somewhere.
Phil Brown..

[Michael Press]

>
> M-gineering" <ikmotgeenspam@m-gineering.nl> wrote in message
> news:fhq0g0$6vj$1@localhost.localdomain...
> > still just me wrote:
> >> I know SImplex used to recommend these for their bar ends. Did it make
> >> much difference? It looks like the amount of leverage gained would be
> >> minimal and offset by the increase in "play" introduced by having
> >> another mechanism in what would otherwise be a single cable. But, I've
> >> never used one. Anyone have experience with one first hand,
> >> maybe before and after?
> >
> > Had one quite a while ago, left it out later, didn't seem to make any
> > difference

In article <4740d782$0$19773$4c368faf@roadrunner.com>,
"Gary Jacobson" <gjacobson@hvc.rr.com> wrote:

> My understanding was that these things were primarily for tandems but used
> on singles too when cables stretched more than they do today.
>
> I asked a similar question a while back as I have some NOS Simplex shifters,
> etc. Seem to remember that Sheldon Brown referenced them in his website
> somewhere too.

Do not top post. I fixed it for you.

Cables do not stretch.

--
Michael Press

[Michael Press]

In article <47425000$0$20631$4c368faf@roadrunner.com>,
"Gary Jacobson" <gjacobson@hvc.rr.com> wrote:

> "Michael Press" <rubrum@pacbell.net> wrote in message
> news:rubrum-47E983.19212018112007@newsclstr02.news.prodigy.com ...
> >>
> >> M-gineering" <ikmotgeenspam@m-gineering.nl> wrote in message
> >> news:fhq0g0$6vj$1@localhost.localdomain...
> >> > still just me wrote:
> >> >> I know SImplex used to recommend these for their bar ends. Did it make
> >> >> much difference? It looks like the amount of leverage gained would be
> >> >> minimal and offset by the increase in "play" introduced by having
> >> >> another mechanism in what would otherwise be a single cable. But, I've
> >> >> never used one. Anyone have experience with one first hand,
> >> >> maybe before and after?
> >> >
> >> > Had one quite a while ago, left it out later, didn't seem to make any
> >> > difference
> >
> > In article <4740d782$0$19773$4c368faf@roadrunner.com>,
> > "Gary Jacobson" <gjacobson@hvc.rr.com> wrote:
> >
> >> My understanding was that these things were primarily for tandems but
> >> used
> >> on singles too when cables stretched more than they do today.
> >>
> >> I asked a similar question a while back as I have some NOS Simplex
> >> shifters,
> >> etc. Seem to remember that Sheldon Brown referenced them in his website
> >> somewhere too.
> >
> > Do not top post. I fixed it for you.
> >
> > Cables do not stretch.
>
> I doubt I'll ever understand the issue with top posting, but I believe you
> on both counts.

Thanks.

> Was all that hullabaloo about die drawn cables years back just marketing?

Probably that and an attempt to make the surface of the cable
smooth and move more easily through the cable housing.

> Are you saying that brake cables don't stretch either?

Yes.
The twisted wire cables themselves do not stretch.
Suppose a cable stretched under load. It would become
thinner, and unable to sustain as much load as
previously, then stretch more. If the cyclist were to
take up the slack at the brake's cable attachment, the
cable could stretch until it parted. This does not
happen. What you see when the brake goes out of
adjustment, seemingly from cable stretch, is in fact
scrunching up (technical term) of the cable housing
ends at various cable stop. Cable stretch is actually
contraction of the cable housing run. The ferrules can
cause contraction of the cable housing run by being the
wrong size, or not completelys seated at installation.
Some cable housing stops should _not_ have ferrules,
and installing them causes shortening of the cable
housing run as the ferrule collapses and the cable
housing sinks into the cable housing stop.

--
Michael Press

[carlfogel@comcast.net]

Dear Gary,

Twisted wire cables do stretch, but not much.

After you listen to all the arguments (which have been made before on
RBT), you can have fun with a cable stretch calculator:

http://www.spaceagecontrol.com/calcstre.htm

Cheers,

Carl Fogel

On Nov 19, 8:09 pm, "Gary Jacobson" <gjacob...@hvc.rr.com> wrote:
> I doubt I'll ever understand the issue with top posting, but I believe you
> on both counts.
> Was all that hullabaloo about die drawn cables years back just marketing?
> Are you saying that brake cables don't stretch either?
>
> Gary Jacobson
> Rosendale, NY

[M-gineering]

still just me wrote:
> I know SImplex used to recommend these for their bar ends. Did it make
> much difference? It looks like the amount of leverage gained would be
> minimal and offset by the increase in "play" introduced by having
> another mechanism in what would otherwise be a single cable.
>
> But, I've never used one. Anyone have experience with one first hand,
> maybe before and after?

Had one quite a while ago, left it out later, didn't seem to make any
difference

--
/Marten

info(apestaartje)m-gineering(punt)nl

[Sheldon Brown]

Someone wrote:
> I know SImplex used to recommend these for their bar ends. Did it make
> much difference?

Actually, yes. The old Simplex derailers were pretty pitiful by
modern standards, and when used with barcons, cable breakage was a
constant issue.

The demultiplier (démultiplicateur in French) mounted down at the
bottom of the seat tube. The section of cable from the shift lever to
the demultiplier was under less tension and traveled farther than the
rear section of cable. This improved cable life and also gave more
lever travel per shift, making it easier to fine tune the non-indexed
shifting.

> It looks like the amount of leverage gained would be
> minimal and offset by the increase in "play" introduced by having
> another mechanism in what would otherwise be a single cable.

Nope. The "mechanism" replaced a the cable guide (or, sometimes a
short length of housing) above the bottom bracket, and the pivot of
the demultiplier actually _reduced_ the friction at this location.

By the way, the QBP "Travel Agent" for brakes is basically the same
thing, only with longer travel than the demultiplier gave.

Sheldon "Mechanical Advantage" Brown

[still just me]

On Mon, 19 Nov 2007 23:19:22 -0800 (PST), carlfogel@comcast.net wrote:

>Dear Gary,
>
>Twisted wire cables do stretch, but not much.
>
>After you listen to all the arguments (which have been made before on
>RBT), you can have fun with a cable stretch calculator:
>
> http://www.spaceagecontrol.com/calcstre.htm
>
>Cheers,
>
>Carl Fogel

Thanks for adding some independent science, Carl.

[Chalo]

Carl Fogel wrote:
>
> Twisted wire cables do stretch, but not much.
>
> After you listen to all the arguments (which have been made before on
> RBT), you can have fun with a cable stretch calculator:
>
> http://www.spaceagecontrol.com/calcstre.htm

For what it's worth, that calculator is for 7x7 rope lay cable, which
in my experience is quite a bit stretchier than the much more common
(for bicycles) 1x19 cable.

49-strand cable, which pops up from time to time in bike applications,
looks good and is more supple than 19-strand cable. But its
elasticity makes it basically useless for brake setups that require
both a large cable actuating force and a long run of cable, e.g. drum
brakes.

A quick spin through the calculator shows that a 200 pound tension (a
50-lb tug on a 4:1 brake lever) upon a 78 inch long cable of 1/16 inch
diameter causes it to stretch about half an inch-- eating up most of
the lever's throw even before housing compression, brake flex, pad
squish, etc. are taken into account. That's consistent with my
experience of 49-strand cable.

One of the chief benefits of the transition to linear-pull brakes has
been the corollary reduction in brake cable tension due to longer
cable travel. Brake system mush attributable to cable stretch is
reduced by almost half compared to earlier brakes.

Chalo

[Michael Press]

In article
<d4769d55-78f4-4bee-9df8-a6e4e5948fc4@e23g2000prf.googl
egroups.com>,
carlfogel@comcast.net wrote:

> Dear Gary,
>
> Twisted wire cables do stretch, but not much.
>
> After you listen to all the arguments (which have been made before on
> RBT), you can have fun with a cable stretch calculator:
>
> http://www.spaceagecontrol.com/calcstre.htm

Are you talking about elastic or plastic deformation?
How much elastic deformation does a bicycle brake cable
undergo at the forces they are designed for?

> On Nov 19, 8:09 pm, "Gary Jacobson" <gjacob...@hvc.rr.com> wrote:
> > I doubt I'll ever understand the issue with top posting, but I believe you
> > on both counts.
> > Was all that hullabaloo about die drawn cables years back just marketing?
> > Are you saying that brake cables don't stretch either?

--
Michael Press

[still just me]

On Tue, 20 Nov 2007 19:46:25 -0800 (PST), Sheldon Brown
<CaptBike@sheldonbrown.com> wrote:

>This improved cable life and also gave more
>lever travel per shift, making it easier to fine tune the non-indexed
>shifting.

Really? More travel per shift? Seems opposite the way you'd want to go
with old style gear and bar cons.

[A Muzi]

> Sheldon Brown <CaptBike@sheldonbrown.com> wrote:
>> This improved cable life and also gave more
>> lever travel per shift, making it easier to fine tune the non-indexed
>> shifting.

still just me wrote:
> Really? More travel per shift? Seems opposite the way you'd want to go
> with old style gear and bar cons.

Works on a no-index tandem, more lever travel really helps locate shifts.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

[frkrygow@gmail.com]

On Nov 21, 3:30 am, Chalo <chalo.col...@gmail.com> wrote:
>
> One of the chief benefits of the transition to linear-pull brakes has
> been the corollary reduction in brake cable tension due to longer
> cable travel. Brake system mush attributable to cable stretch is
> reduced by almost half compared to earlier brakes.

Ditto for cable friction. Friction force around bends also gets worse
with tension. It's one of those self-perpetuating (or self-
amplifying) problems.

I assume that's the reason that brake levers now have their own return
springs, plus the little clips that keep the cable heads in place.
Lightly pushing the cable back from the lever end means less spring
tension is required at the caliper end. Then, during brake
application, the cable's under less tension, so there's less friction
in the bends. The benefit is larger than one might think.

- Frank Krygowski

[_]

On Wed, 21 Nov 2007 12:34:11 -0600, A Muzi wrote:

>> Sheldon Brown <CaptBike@sheldonbrown.com> wrote:
>>> This improved cable life and also gave more
>>> lever travel per shift, making it easier to fine tune the non-indexed
>>> shifting.
>
> still just me wrote:
>> Really? More travel per shift? Seems opposite the way you'd want to go
>> with old style gear and bar cons.
>
> Works on a no-index tandem, more lever travel really helps locate shifts.

So do long levers, à là Huret.

[still just me]

On Wed, 21 Nov 2007 18:05:14 -0800 (PST), frkrygow@gmail.com wrote:

>I assume that's the reason that brake levers now have their own return
>springs, plus the little clips that keep the cable heads in place.
>Lightly pushing the cable back from the lever end means less spring
>tension is required at the caliper end. Then, during brake
>application, the cable's under less tension, so there's less friction
>in the bends. The benefit is larger than one might think.

That may be true, but it has little to do with cable stretch. We used
to string brakes all the time, day after day. Ferrules always fit and
housing ends were always ground flat. Hook them up tight, give a few
hard pulls on the levers, and guess what? Cable slack. It wasn't the
housing, or the fittings, or friction - it was cable stretch.

After the initial pulls, the problem seems to abate to undetectable
levels.

[frkrygow@gmail.com]

On Nov 22, 1:56 am, still just me <wheeledBobNOS...@yahoo.com> wrote:
> On Wed, 21 Nov 2007 18:05:14 -0800 (PST), frkry...@gmail.com wrote:
> >I assume that's the reason that brake levers now have their own return
> >springs, plus the little clips that keep the cable heads in place.
> >Lightly pushing the cable back from the lever end means less spring
> >tension is required at the caliper end. Then, during brake
> >application, the cable's under less tension, so there's less friction
> >in the bends. The benefit is larger than one might think.
>
> That may be true, but it has little to do with cable stretch.

Right. And I didn't say it did. It's just a related topic, a
progression of the conversation.

> We used
> to string brakes all the time, day after day. Ferrules always fit and
> housing ends were always ground flat. Hook them up tight, give a few
> hard pulls on the levers, and guess what? Cable slack. It wasn't the
> housing, or the fittings, or friction - it was cable stretch.
>
> After the initial pulls, the problem seems to abate to undetectable
> levels.

I think that's not cable stretch either... at least, not most of it.
Here's what I think is happening:

You're snaking a cable through a housing that curves in three
dimensions. And many housings are lined with relatively soft
plastic. When you did your original setup, the cable and housing were
not in their final equilibrium position.

When you gave the hard pull on the levers, you were imparting much
more tension than you'd done during the setup. The cables shifted
slightly inside the housing, finding the shortest path from lever to
brake. They may have also squashed the plastic liner a bit. And the
housings probably also shifted position on curves. And despite what
you think, I'd bet the ferrules seated a bit more under the large
force. All this adds up to extra slack that has to be adjusted out.

My bet is that if you precisely measured a new cable length, did the
install as you described (including the hard squeeze and re-adjust)
then stripped out the cable out and precisely re-measured, you'd find
the cable length to be exactly the same.

(And even if there were any change in length, it would be very slight,
and perhaps due to some similar "settling" of the individual strands,
not actual linear stretching of the metal.)

This might be a good project for Fogel Labs, should he choose to
accept it.

- Frank Krygowski

[still just me]

On Thu, 22 Nov 2007 09:39:49 GMT, _
<jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com> wrote:

>>> Sheldon Brown <CaptBike@sheldonbrown.com> wrote:
>>>> This improved cable life and also gave more
>>>> lever travel per shift, making it easier to fine tune the non-indexed
>>>> shifting.
>>
>> still just me wrote:
>>> Really? More travel per shift? Seems opposite the way you'd want to go
>>> with old style gear and bar cons.
>>
>> Works on a no-index tandem, more lever travel really helps locate shifts.
>
>So do long levers, à là Huret.

Well, I think my question is answered anyway. I can't stand the feel
of long levers and long pulls. I thought the de-multiplicator's intent
was to give me positive leverage effect, not negative. Friction
bar-ends don't need more slop!

[Joe Riel]

frkrygow@gmail.com writes:

> On Nov 22, 1:56 am, still just me <wheeledBobNOS...@yahoo.com> wrote:
>> On Wed, 21 Nov 2007 18:05:14 -0800 (PST), frkry...@gmail.com wrote:
>> >I assume that's the reason that brake levers now have their own return
>> >springs, plus the little clips that keep the cable heads in place.
>> >Lightly pushing the cable back from the lever end means less spring
>> >tension is required at the caliper end. Then, during brake
>> >application, the cable's under less tension, so there's less friction
>> >in the bends. The benefit is larger than one might think.
>>
>> That may be true, but it has little to do with cable stretch.
>
> Right. And I didn't say it did. It's just a related topic, a
> progression of the conversation.
>
>> We used
>> to string brakes all the time, day after day. Ferrules always fit and
>> housing ends were always ground flat. Hook them up tight, give a few
>> hard pulls on the levers, and guess what? Cable slack. It wasn't the
>> housing, or the fittings, or friction - it was cable stretch.
>>
>> After the initial pulls, the problem seems to abate to undetectable
>> levels.
>
> I think that's not cable stretch either... at least, not most of it.
> Here's what I think is happening:
>
> You're snaking a cable through a housing that curves in three
> dimensions. And many housings are lined with relatively soft
> plastic. When you did your original setup, the cable and housing were
> not in their final equilibrium position.
>
> When you gave the hard pull on the levers, you were imparting much
> more tension than you'd done during the setup. The cables shifted
> slightly inside the housing, finding the shortest path from lever to
> brake. They may have also squashed the plastic liner a bit. And the
> housings probably also shifted position on curves. And despite what
> you think, I'd bet the ferrules seated a bit more under the large
> force. All this adds up to extra slack that has to be adjusted out.
>
> My bet is that if you precisely measured a new cable length, did the
> install as you described (including the hard squeeze and re-adjust)
> then stripped out the cable out and precisely re-measured, you'd find
> the cable length to be exactly the same.
>
> (And even if there were any change in length, it would be very slight,
> and perhaps due to some similar "settling" of the individual strands,
> not actual linear stretching of the metal.)
>
> This might be a good project for Fogel Labs, should he choose to
> accept it.

A simple test is to replace the cable, but leave the housing.

--
Joe Riel

[Joe Riel]

still just me <wheeledBobNOSPAM@yahoo.com> writes:

> Well, I think my question is answered anyway. I can't stand the feel
> of long levers and long pulls. I thought the de-multiplicator's intent
> was to give me positive leverage effect, not negative.

Wouldn't negative leverage result in an unstable system?

--
Joe Riel

[still just me]

On Thu, 22 Nov 2007 07:58:10 -0800, Joe Riel <joer@san.rr.com> wrote:

>> (And even if there were any change in length, it would be very slight,
>> and perhaps due to some similar "settling" of the individual strands,
>> not actual linear stretching of the metal.)
>>
>> This might be a good project for Fogel Labs, should he choose to
>> accept it.
>
>A simple test is to replace the cable, but leave the housing.

Except that if it's "settling" of the whole system as suggested, then
you'd reintroduce that factor.

I'm not sure I buy into the "shortest path" theory. We'd pull cables
very tight, in hopes that the adjustment would be close enough to
allow just a slight twist on the barrel adjuster to pull out the
slack. (Most of the time that didn't work out as planned, there'd be
too much stretch and we'd have to make a major adjustment at the
barrel... enough so that good conscience and good workmanship required
us to readjust the barrel to a mid point and redo the cable). But, I
don't think there way a possibility of much slack.

I suppose the only way to settle it scientifically would be to measure
the maximum load that you can generate with the lever, then apply that
to a new cable in a pure stretch test (no housings, point to point)
and see what happens.

FWIW, and as Carl's suggested site indicates, it's not so much the
steel stretch as it is the individual strands settling into place
within the cable.

[Michael Press]

In article
<s3abk3111rrk470ljd4mbvqnf6n15hl7kc@4ax.com>,
still just me <wheeledBobNOSPAM@yahoo.com> wrote:

> On Thu, 22 Nov 2007 07:58:10 -0800, Joe Riel <joer@san.rr.com> wrote:
>
> >> (And even if there were any change in length, it would be very slight,
> >> and perhaps due to some similar "settling" of the individual strands,
> >> not actual linear stretching of the metal.)
> >>
> >> This might be a good project for Fogel Labs, should he choose to
> >> accept it.
> >
> >A simple test is to replace the cable, but leave the housing.
>
> Except that if it's "settling" of the whole system as suggested, then
> you'd reintroduce that factor.
>
> I'm not sure I buy into the "shortest path" theory. We'd pull cables
> very tight, in hopes that the adjustment would be close enough to
> allow just a slight twist on the barrel adjuster to pull out the
> slack. (Most of the time that didn't work out as planned, there'd be
> too much stretch and we'd have to make a major adjustment at the
> barrel... enough so that good conscience and good workmanship required
> us to readjust the barrel to a mid point and redo the cable). But, I
> don't think there way a possibility of much slack.
>
> I suppose the only way to settle it scientifically would be to measure
> the maximum load that you can generate with the lever, then apply that
> to a new cable in a pure stretch test (no housings, point to point)
> and see what happens.

Yes. Anchor points of the cable must be taken out of
the measurement, because obfuscating deformation
can occur at the anchors. Must measure between two points
of the straight cable span.

>
> FWIW, and as Carl's suggested site indicates, it's not so much the
> steel stretch as it is the individual strands settling into place
> within the cable.

--
Michael Press