From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Opening a Sachs Power link
Date: 13 Nov 1999 21:14:57 GMT

K. Olbrantz writes:

> Once I have ridden a chain with one of these, I can not get it to
> come apart to remove chain.

From the FAQ:
---------------------------------------------------------------------
Subject: 8d.5   SACHS Power-links
From: Jobst Brandt <jbrandt@hpl.hp.com>
Date: Wed, 12 May 1999 15:38:14 PDT

The SACHS Power-link, can be separated easily alone but not when in a
chain.  The link is designed not to open by axial compression alone,
typically when a new chain is used on worn sprockets, where skipping
over teeth can cause inertial compression by the trailing chain.  To
prevent this occurrence, a recess around the head of the stepped pin
makes more than a half circle, preventing the pin from sliding in its
slot.  That means the side plates of the link must be pressed
together, taking up side clearance, to raise the head of the sliding
pin above this retention.

To open the chain, find the link, make an upside down U-shape of the
chain with the link as the cross bar, the adjacent chain hanging down,
grasp the link diagonally with pliers across the the corners to which
the pins are fixed, not the corners with the keyhole slot.  Pushing
the side plates together assists removal but is not essential, the
diagonal force having a lateral compressive component.

Before using a Power-link, put it together to see why it does not
readily slide from closed to open position.  Road grit makes this even
more difficult.

------------------------------

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Sram Power Link Problem
Date: 30 May 2000 22:10:49 GMT

Brian Lafferty writes:

> Or the new manufacturing facility is not as careful in its production
> as Sachs?  I think that's what Richard was thinking of.  Sort of
> like when Peugeot moved some of its production to Quebec, you needed
> a rubber mallot and reaming tool to put a bike together.

Sounds like myth and lore to me.

> What is your explanation for the problem I've encountered with the
> Sram Power Link?  It seems to me that there is not the clearance to
> depress the link slightly to get it to release nor to get it to snap
> in to engage.  Any ideas?  As I posted before, I've never had this
> problem with a Sachs chain.

This isn't special relativity.  The Power Link can be inspected before
assembly, be engaged and disengaged, and can then be installed.
Without understanding what the mechanism of engagement is, this can be
difficult.  As has been discussed here at length, the link has
disengagement problems with a dirty chain, where the side plate
clearance is not free of dirt and cannot be compressed.  The side
plates must be pressed inward to allow disengagement.  The link has
key hole shaped slots and these must be positioned so the heads of the
pins rise out of their recesses that are more then 180 degrees.

As I pointed out, the easiest way to do this is to use pliers
diagonally across the link lengthwise pressing the fixed pin ends
together.  Unless the chain is sparklingly clean, this is the only
method I have found that works without fumbling.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Sram Power Link Problem
Date: 30 May 2000 23:11:22 GMT

Brian Lafferty writes:

>> This isn't special relativity.  The Power Link can be inspected
>> before assembly, be engaged and disengaged, and can then be
>> installed.  Without understanding what the mechanism of engagement
>> is, this can be difficult.  As has been discussed here at length,
>> the link has disengagement problems with a dirty chain, where the
>> side plate clearance is not free of dirt and cannot be compressed.

> These were both new chains with no dirt, never ridden outside.

>> The side plates must be pressed inward to allow disengagement.  The
>> link has key hole shaped slots and these must be positioned so the
>> heads of the pins rise out of their recesses that are more then 180
>> degrees.

> Once connected, the links, on two chains (same production run?)
> could not be compressed, even with a plier.  I'll just have to wait
> for the next chain to see if the same thing happens.  I will find
> and hide away a few Sachs made chains in the meantime.

Something doesn't add up here.  If you can get it together then you
can get it apart, the process being reversible.  How do you explain
that the chain went together?  If the power link would not seat
manually, that is, you had to apply pedal tension to the chain, then
that was your mistake.  If it went together manually on insertion,
then it would be reversibly disconnected the same way.

I'm no great fan of this device but it is easier than a chain breaker
and can be released using any old pair of pliers instead of having to
carry a chain breaker.  The ones I have will come apart manually if
you fiddle with it long enough to displace any grit that at first
prevents pressing the side plates together.  However, I have not had
the need to open a chain underway except in cases of mechanical
failure, so this has not been a problem.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Sram Power Link Problem
Date: 31 May 2000 19:12:24 GMT

Brian Lafferty writes:

>>> My understandoing is that if you use the chain breaker on a chain
>>> with mushroomed pins you may find the chain breaking at an
>>> inopportune moment on the road after reassembly.

>> You understand incorrectly.  The chain is as versatile as it was
>> before Powerlink came along.  It is easily opened and closed with a
>> chain tool.  Fear mongering will get you no points.

> Now explain to me what effect pushing the mushroomed pin head
> through the side plate both inward and outward in the
> disconnect/reconnect process has or does not have.

Your presupposition that the pins have rivet heads is incorrect.  If
you press out such a pin, something that must occur when you remove a
piece of chain, the hole would be uselessly broached out.  Pressing it
back in would double the damage.  Empirical evidence from many
thousand chains used in this manner proves that this scenario is not
real.

> Does the plate or the pin give way to allow passage of the
> mushroomed head?  Is the hole in the side plate deformed in the
> process?

Apparently not to any effect.  This is the way chains have been used
for a long time.  In contrast, many motorcycle chains break off part
of the riveted head of the pin when the side plate is removed.  They
do not use a pin press to push the pin out but rather use a plate
extractor that pulls off the side plate.  These chains demand a master
link.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Sram Power Link Problem
Date: 1 Jun 2000 15:42:48 GMT

Mike DeMicco writes:

> OK then why do the chain manufacturers peen over the ends of the
> pins?  Doesn't the peening make the chain stronger? Don't you remove
> the peening when you push the pin in? Why then does Shimano have
> that special pin that you're supposed to use to replace the pin that
> you pushed in?

As often, this subject is gradually metamorphosing into Shimano chains
and special pins.  The discussion was whether and how Power Links are
installed and opened and whether one can use a chain tool to do the
same without a Power Link.  I think the answer is clear, you can and
it does work.

Now you are posing rhetorical questions to put forth your perception
of what one should do.  If you know what it is, why not be straight
forward about it and state it.  It seems we are getting more and more
Bob Mitke presentations that are entirely made of leading questions.

As to the Shimano pins... they are used because the pins are flush,
square edged and do not readily reinsert without broaching the side
plate bore.  A pin with a tapered end that breaks off, avoids this
problem although the original pin could theoretically be reinserted.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Sram Power Link Problem
Date: 3 Jun 2000 23:21:14 GMT

Brian Lafferty writes:

> I'm still waiting for an answer to the Sram rivet question.  Jobst?
> Jobst?

Your question suggests that you missed part of this thread or you
would know that I use a chain tool to press out pins and reinstall
them and have no problems with the chain falling apart.  Whether the
pins have fatter ends from riveting or not is not a hindrance to
pressing the pin out far enough to separate the chain and to re-engage
it reliably.

What exactly don't you understand about that?

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Super Link Lives!
Date: 16 Oct 2000 17:32:13 GMT

John Everett writes:

> I just realized I posted yesterday's article on the subject in a
> somewhat obscure and old thread. So here's the news:

> I just received the new Super Links I ordered from Lickton's
> (http://www.lickbike.com), and they are the good old (and long
> unavailable) Craig Metalcraft Super Links, only now manuactured by
> Forster Tool & Manufacturing of Bensenville, Illinois. I've examined
> them with a magnifying glass side-by-side with an old Craig Super
> Link, and to my eyes they are absolutely identical, down to the "S"
> engraving and the tiny little "SUPERLINK III" around the pin hole.
> (See illustration at: http://kato.theramp.net/craig/sl.gif)

Well if the picture you reference is correct then this Super Link is
inferior to the SRAM Powerlink shown at:

http://www.sram.com/product/chain/powerlink/powerlink.html

If you look carefully, you'll see that the mushroom head of the SRAM
link drops into a recess in the link face that prevents it from
sliding apart unless the side plates are both pressed inward, taking up
all the operating clearance.  This feature is important to prevent
inadvertent separation when shifting and a chain jump occurs and
especially if the chain skips on a used sprocket.  In spite of this
feature, that some riders dislike, I have had a clean chain disengage
when the chain skipped on a used sprocket.  I retrieved the link from
the road and reinserted it for long full useful service.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Super Link Lives!
Date: 16 Oct 2000 22:36:55 GMT

Richard Ney writes:

> What is the value in using these links?  When I break the chain
> (Sachs) to clean it, I simply use a chain tool.  It takes little time
> to do this.  Are these links simply a convenience for those who
> don't want to use tools, or am I damaging my chain in some way by
> breaking it at any random link?

When removing a chin using a tool to press out a pin, you must have
that tool and use it, and the pushed out pin must be just far enough
out to retain the chain together for reassembly but loose enough so
that it can be manually separated.  When this is done correctly the
pin is retained in the rearward end of the bottom run of the chain.
If this is done the opposite way, the freewheel makes removal a one
way process and in this direction chain cannot be pulled out of the
derailleurs because the extended pin will not pass through them
easily.

When re-installing the chain, the pin must be pressed in again using
the chain tool used to separate it but clearance must be introduced to
make it articulate freely while paying attention to insertion so that
the pin extends equally from both sides.

With a Powerlink, this reduces to no tool and no adjustment, and there
is no protruding pin when removing the chain.  At worst, one must take
ordinary pliers and squeeze the link diagonally across its two "heels"
to make it pop off.  It does this without force and often can be done
by hand.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Super Link Lives!
Date: 17 Oct 2000 01:01:26 GMT

Richard Ney writes:

> I take it then that Power Links/Super Links are merely a
> convenienece; that breaking the chain as I outlined previously
> neither harms nor weakens the chain.

Only if done improperly and I've seen enough of these where the chain
popped open.  The Powerlink does not leave room for that sort of
error.  That one came open on my bike is typical in that most things
that can happen have happened on my bike.  The only difference is that
I was able to analyze what happened, go back, find the link half and
continue.  Others might have written it of as a faulty link and sworn
them off forever after.  I use them and like them.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: SRAM Power Link-Does it work?
Date: 21 Mar 2001 02:06:18 GMT

Chris Wheelman writes:

>> "Can you tell us how why you believe >using a chain tool to break a
>> chain can significantly weaken it? "

> Yes. Every time you push out the pin, the hole which it is tightly press
> fit into gets worn a little bit bigger and a little bit looser.

> Other damage can occur as well during the disassembly/installation.
> This all can eventually lead to the pin releasing during hard pedaling.

This implies that the press is inelastic, which it is not, and that
one selectively presses the same pin in and out several times, if not
many.  This sounds good to the uncritical listener but it isn't true.
The reason this is bashed around is that there is always someone
unclear on the concept, who doesn't make sure that the pin has equal
overstand after insertion and that when a pin doesn't go in easily,
broaching force should not be used to make it go in anyway.  That tale
is a red herring except for chains like Rholoff where the corners of
pins break off when pushed out.

As I said, in my many years of riding, I have not experienced a chain
failure of anyone on my rides, and for me the only chain that came
apart was an SRAM PowerLink that had been ridden no more than 10 miles
in the hills when a chain skip compressed it and fell out.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jobst.brandt@stanfordalumni.org
Subject: Re: Can't 'snap' chain!
Newsgroups: rec.bicycles.tech
Message-ID: <nFwjd.4037$_3.46692@typhoon.sonic.net>
Date: Sun, 07 Nov 2004 21:42:43 GMT

Mark SA? writes:

> For the life of me I cannot get apart the snap link on my new chain.

> I have a Connexe Wipperman chain, I can open that with one hand!  I
> have a SRAM Powerlink chain on the other bike...again no problem.

> The chain on my new bike has no name on it, however the 'snap link'
> looks exactly like the SRAM.  When I push the links together the
> plates slide in but not enough for me to get the chain apart.

Forget about the 'by hand" option and I believe the link you are
working with is the same as SRAM and would work the same except that
from my experience, a little road grit between the side plates
prevents sufficient compression as you describe.  I have had to use
pliers diagonally across the link, heel-to-heel and apply pressure.

This is enough to crunch the grit and disengage the link.  I can't
angle the ASCII arrows below but they are to point diagonally across
the link.  This worked nicely for me when I was using the PowerLink.
I don't use these links any more with my SRAM chains and just push the
pin out and back in to connect chain ends as we always did.  If it
takes a tool then I might as well not use special links.

  ->  -|--------
       |      |
      --------|-  <-

Jobst Brandt
jobst.brandt@stanfordalumni.org

From: jobst.brandt@stanfordalumni.org
Subject: Re: Can't 'snap' chain!
Newsgroups: rec.bicycles.tech
Message-ID: <mAyjd.4067$_3.47079@typhoon.sonic.net>
Date: Sun, 07 Nov 2004 23:53:54 GMT

Tom Sherman writes:

>>> For the life of me I cannot get apart the snap link on my new
>>> chain.

>>> I have a Connexe Wipperman chain, I can open that with one hand!
>>> I have a SRAM Powerlink chain on the other bike...again no
>>> problem.

>>> The chain on my new bike has no name on it, however the 'snap
>>> link' looks exactly like the SRAM.  When I push the links together
>>> the plates slide in but not enough for me to get the chain apart.

>> Forget about the 'by hand" option and I believe the link you are
>> working with is the same as SRAM and would work the same except
>> that from my experience, a little road grit between the side plates
>> prevents sufficient compression as you describe.  I have had to use
>> pliers diagonally across the link, heel-to-heel and apply pressure.

>> This is enough to crunch the grit and disengage the link.  I can't
>> angle the ASCII arrows below but they are to point diagonally
>> across the link.  This worked nicely for me when I was using the
>> PowerLink.  I don't use these links any more with my SRAM chains
>> and just push the pin out and back in to connect chain ends as we
>> always did.  If it takes a tool then I might as well not use
>> special links.

>>
>>   ->  -|--------
>>        |      |
>>       --------|-  <-

> Are you still using a 6-speed freewheel with a (presumably) wide
> chain?

I don't know what you call a wide chain but I am using what was
prescribed for 7/8-speed clusters.  The SRAM pins barely protrude and
they go in and out nicely with chain pliers.

> I have been able to reuse pins in 7/8 speed chains with no problem,
> but have found it impossible to even get the chain back together
> with the same pin on some 9-speed chains. In particular, 9-speed
> Shimano chains require either a special Shimano pin or a reusable
> link from another manufacturer.

I haven't progressed to that unwieldy phase yet.  I get along fine
with a 13..24t cluster with two CW's.  I don't believe I need to slice
the gears any finer gradation than I have.  When I bought the big box
of SRAM chain, it came with PowerLinks.  I still have plenty of these
however, my experience with them was not what I call convenience.

In fact, on the first chain with which I used a PowerLink link I had
worn sprockets that allowed the chain to skip under load.  After about
50 miles of use, one of the chain skips occurred at exactly the right
moment so that the link landed just before the cluster, where it was
compressed by chain momentum and fell out.  I found the two parts
lying on the road, reconnected the chain and rode it until the chain
was worn out.  Between that and not being able to separate a dirty
chain manually, I decided against PowerLink.

Jobst Brandt
jobst.brandt@stanfordalumni.org