? To Measure Cog Wear



P

Paul Kopit

Guest
Is there a way to measure the wear to cassette cogs? I know when I
replace a chain that has worn beyond 1/8" in 12" that the cogs may be
shot, but not always. The way I tell is to ride the bike and see if
the new chain skips. That's fine if you want to go riding the bike
and putting pressure on each cog.

I just replaced an overworn chain on a Campy 13/29 x Chorus cassette
(53/39 rings). The rider told me that the cassette was skipping on
19t cog. I have a 19/21 spidered cog(s) but how do I know the
conditon of other cogs?
 
Paul Kopit wrote:

> Is there a way to measure the wear to cassette cogs?
Rohloff makes a nice device that measures wear of Shimano cogs: Rohloff
HG-IG check.

Derk
 
Paul Kopit wrote:
> Is there a way to measure the wear to cassette cogs? I know when I
> replace a chain that has worn beyond 1/8" in 12" that the cogs may be
> shot, but not always. The way I tell is to ride the bike and see if
> the new chain skips. That's fine if you want to go riding the bike
> and putting pressure on each cog.
>
> I just replaced an overworn chain on a Campy 13/29 x Chorus cassette
> (53/39 rings). The rider told me that the cassette was skipping on
> 19t cog. I have a 19/21 spidered cog(s) but how do I know the
> conditon of other cogs?
>
You may be able to see the wear by looking at brand new cogs next to the
suspect ones. Or flip the cog over. New cogs are symmetric, wear is
decidedly asymmetric.

Merely being able to see the effect does not quantify it, however. The
practical answer is, as you know, 'if it skips with a new chain, replace
it'. I do not believe any measuring tool, at least none I've seen, can
tell you that. An accurate cog wear measuring tool would have to allow
for each brand in each tooth size; not likely.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
A Muzi <[email protected]> writes:

>You may be able to see the wear by looking at brand new cogs next to the
>suspect ones. Or flip the cog over. New cogs are symmetric, wear is
>decidedly asymmetric.

This is a good point ; what are you gonna do with a cog-wear tool -
who makes cogs that can be flipped over ?? I know that Miche makes
them, but I was wondering about other brands? I would expect this to
be taboo among the major manufacturers as they would quite possibly
sell only half as many cogs.

Many of the fabulous advantages of cassettes have been vetoed by
marketing nitwhits : flippable cogs, individual cogs, custom ratios
"too cheap to charge for!" ad nauseum ...

- Don Gillies
San Diego, CA
 
> A Muzi <[email protected]> writes:

Donald Gillies wrote:
>> You may be able to see the wear by looking at brand new cogs next to the
>> suspect ones. Or flip the cog over. New cogs are symmetric, wear is
>> decidedly asymmetric.
>
> This is a good point ; what are you gonna do with a cog-wear tool -
> who makes cogs that can be flipped over ?? I know that Miche makes
> them, but I was wondering about other brands? I would expect this to
> be taboo among the major manufacturers as they would quite possibly
> sell only half as many cogs.
>
> Many of the fabulous advantages of cassettes have been vetoed by
> marketing nitwhits : flippable cogs, individual cogs, custom ratios
> "too cheap to charge for!" ad nauseum ...

Sorry, I meant flip the cog over to _observe_ the asymmetry of worn
teeth. There are valid reasons for making cogs one-position-only. I
wasn't carping about that.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
Donald Gillies wrote:

> who makes cogs that can be flipped over ??
Rohloff ?

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl
 
A Muzi wrote:
I do not believe any measuring tool, at least none I've seen, can
> tell you that. An accurate cog wear measuring tool would have to allow
> for each brand in each tooth size; not likely.

not if your starting point is that the cogs should work with a standard
chain, which is the aspect all cogs share
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl
 
In article <[email protected]>,
[email protected] (Donald Gillies) wrote:

> A Muzi <[email protected]> writes:
>
> >You may be able to see the wear by looking at brand new cogs next to the
> >suspect ones. Or flip the cog over. New cogs are symmetric, wear is
> >decidedly asymmetric.
>
> This is a good point ; what are you gonna do with a cog-wear tool -
> who makes cogs that can be flipped over ?? I know that Miche makes
> them, but I was wondering about other brands? I would expect this to
> be taboo among the major manufacturers as they would quite possibly
> sell only half as many cogs.
>
> Many of the fabulous advantages of cassettes have been vetoed by
> marketing nitwhits : flippable cogs, individual cogs, custom ratios
> "too cheap to charge for!" ad nauseum ...

We traded the first one for much better shifting, and the last two are
rendered a little silly when you realize a 9 or 10-speed 11-25 probably
has every ratio Eddy ever used in any road race he ever did, plus one or
two he didn't yet have.

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos
 
Ryan Cousineau wrote:

> We traded the first one for much better shifting, and the last two are
> rendered a little silly when you realize a 9 or 10-speed 11-25 probably
> has every ratio Eddy ever used in any road race he ever did, plus one or
> two he didn't yet have.
>

Nope, it doesn't have an 18, which was a definite 'must have' cog
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl
 
In article <[email protected]>,
M-gineering <[email protected]> wrote:

> Ryan Cousineau wrote:
>
> > We traded the first one for much better shifting, and the last two are
> > rendered a little silly when you realize a 9 or 10-speed 11-25 probably
> > has every ratio Eddy ever used in any road race he ever did, plus one or
> > two he didn't yet have.
> >
>
> Nope, it doesn't have an 18, which was a definite 'must have' cog

Well, there you go then. I was hoping we could finally find a
justification for 11-speed.

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos
 
[email protected] wrote:

> Thanks for that link. I did not know such a tool existed.
I use it quite often and it's very accurate. When it's difficult to push the
last link of the tool on the cog, you're certain your new chain will skip
on that cog.

> I would rather measure the cog wear myself, than trust someone else's
>opinion.
Same here :)

> Especially if they want to sell you a new cassette, when you might not
> really need one yet - J.
That's the reason I bought this tool myself. It's quite affordable btw.

Gr, Derk
 
On May 9, 10:45 am, Derk <[email protected]> wrote:
> [email protected] wrote:
> > Thanks for that link. I did not know such a tool existed.
>
> I use it quite often and it's very accurate. When it's difficult to push the
> last link of the tool on the cog, you're certain your new chain will skip
> on that cog.
>
> > I would rather measure the cog wear myself, than trust someone else's
> >opinion.
>
> Same here :)
>
> > Especially if they want to sell you a new cassette, when you might not
> > really need one yet - J.
>
> That's the reason I bought this tool myself. It's quite affordable btw.
>
> Gr, Derk

I agree with the others, in that the most accurate way to tell if your
particular cassette needs to be replaced, is if a new chain skips.
When my current bike was 6 months old (1800 road miles), I had
shifting trouble. My LBS sold me a new chain and cassette. I doubt
that the cassette needed to be replaced, but I did not have any way to
determine cassette wear at that time. I have not seen enough worn out
cassettes to know one when I see one.

I think the new chain, and a derailleur adjustment, was all that was
needed. It is like the time a LBS told me they rebuilt my BB. I only
found out weeks later that my BB is a sealed cartridge unit. So who
knows what I actually paid for.

I will probably buy the tool because I like to have as much data as
possible, regarding bike trouble diagnosis - J.
 
On May 9, 9:51 am, "[email protected]" <[email protected]> wrote:
> On May 9, 10:45 am, Derk <[email protected]> wrote:
>
>
>
>
>
> > [email protected] wrote:
> > > Thanks for that link. I did not know such a tool existed.
>
> > I use it quite often and it's very accurate. When it's difficult to push the
> > last link of the tool on the cog, you're certain your new chain will skip
> > on that cog.
>
> > > I would rather measure the cog wear myself, than trust someone else's
> > >opinion.
>
> > Same here :)
>
> > > Especially if they want to sell you a new cassette, when you might not
> > > really need one yet - J.
>
> > That's the reason I bought this tool myself. It's quite affordable btw.
>
> > Gr, Derk
>
> I agree with the others, in that the most accurate way to tell if your
> particular cassette needs to be replaced, is if a new chain skips.

Is a skipping chain the only sign of a worn-out cassette or cog? My
chain doesn't skip, but my drive train seems a bit noisy and no amount
of adjustment on the front helps (I have bar end shifters and infinite
adjust of the chain-line on the front chainrings). The chain is
pretty new, so I've been wondering if it's time to replace the
cassette. Lubing helps some, but only for 20 miles or so. Also, it's
noisier in some cogs than others.

Jenn
 
On May 9, 12:33 pm, thejen12 <[email protected]> wrote:
> On May 9, 9:51 am, "[email protected]" <[email protected]> wrote:
>
>
>
>
>
> > On May 9, 10:45 am, Derk <[email protected]> wrote:
>
> > > [email protected] wrote:
> > > > Thanks for that link. I did not know such a tool existed.
>
> > > I use it quite often and it's very accurate. When it's difficult to push the
> > > last link of the tool on the cog, you're certain your new chain will skip
> > > on that cog.
>
> > > > I would rather measure the cog wear myself, than trust someone else's
> > > >opinion.
>
> > > Same here :)
>
> > > > Especially if they want to sell you a new cassette, when you might not
> > > > really need one yet - J.
>
> > > That's the reason I bought this tool myself. It's quite affordable btw.
>
> > > Gr, Derk
>
> > I agree with the others, in that the most accurate way to tell if your
> > particular cassette needs to be replaced, is if a new chain skips.
>
> Is a skipping chain the only sign of a worn-out cassette or cog? My
> chain doesn't skip, but my drive train seems a bit noisy and no amount
> of adjustment on the front helps (I have bar end shifters and infinite
> adjust of the chain-line on the front chainrings). The chain is
> pretty new, so I've been wondering if it's time to replace the
> cassette. Lubing helps some, but only for 20 miles or so. Also, it's
> noisier in some cogs than others.
>
> Jenn- Hide quoted text -
>
> - Show quoted text -

With my very limited experience, all I can suggest is the 1st two
paragraphs of the Chains section in this link
http://www.bitrot.de/bbook_drive.html . Also, as has been suggested,
if you have a new cassette available, visually compare them side-by-
side. How many chains have you used on this cassette? Also, if you
tend to ride in only a couple of the cogs, those could be
significantly worn, while the other cogs are fine - J.
 
A Muzi wrote:

> I do not believe any measuring tool, at least none I've seen,
> can tell you that. An accurate cog wear measuring tool would
> have to allow for each brand in each tooth size; not likely.

This was my first thought as well. But having looked at the
Rohloff tool, I see it's just a piece of chain with a lever for
simulating peddling pressure. If this new-spec chain sits
deeply enough into sprocket wear pockets under pressure, the
end link won't slip between adjoining teeth easily.

That's an accurate test, exactly mimicing reality. The only
unknown variable is the new chain itself. I've found that some
brands are a little more inclined to skip than others.

John
 
"John Henderson" <[email protected]> wrote in message
news:[email protected]...
>A Muzi wrote:
>
>> I do not believe any measuring tool, at least none I've seen,
>> can tell you that. An accurate cog wear measuring tool would
>> have to allow for each brand in each tooth size; not likely.
>
> This was my first thought as well. But having looked at the
> Rohloff tool, I see it's just a piece of chain with a lever for
> simulating peddling pressure. If this new-spec chain sits
> deeply enough into sprocket wear pockets under pressure, the
> end link won't slip between adjoining teeth easily.
>
> That's an accurate test, exactly mimicing reality. The only
> unknown variable is the new chain itself. I've found that some
> brands are a little more inclined to skip than others.
>
> John

So it appears this tool has nothing to offer. If the new chain skips on the
repair stand, and it did not skip previously, replace cassette. And pocket
the $25, which was not spent on the tool.

I guess that is why I like to read what you bike experts have time to
contribute - J.
 
> Ryan Cousineau wrote:
>> We traded the first one for much better shifting, and the last two are
>> rendered a little silly when you realize a 9 or 10-speed 11-25
>> probably has every ratio Eddy ever used in any road race he ever did,
>> plus one or two he didn't yet have.

M-gineering wrote:
> Nope, it doesn't have an 18, which was a definite 'must have' cog

Yup. Even my six speed as a 17 and an 18 in the middle.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
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