Worn out chainrings?

[travis.harry@gmail.com]

I've spent hours searching in groups. Maybe there's a NEW approach to
this.

I've a pile of used chainrings. Just as if I had a pile of used
chains, I'd like to describe their wear. How to do it?

I tried putting a 5 inch length of new SRAM PC58 chain on each ring,
holding down the last links and pulling up; also moving the length of
chain around the rings. For comparison with used chainrings I had 3
new rings. A circa-1995 Campagnolo 53t ring and a new 1985 Takagi 52t.
Both rings were ground and should represent quality machining. I also
had a new old stock 52 t 144bcd ring by ???

Aside from visually obvious wear to the face of the teeth of some used
rings, I could not say that the movement of the chainon the used
chains differentiated them from the movement on the new ones. There
was as much difference between the new chainrings as there was between
new and used.

This isn't academic if I'd like to predict how the ring will perform,
for me or someone else, or if I'd like to be sure the ring will not
excessively wear or damage a new chain, and then cassette sprockets.

So what is the metric, besides "chain skips on it under load" and
"teeth look hooked?

[A Muzi]

travis.harry@gmail.com wrote:
> I've spent hours searching in groups. Maybe there's a NEW approach to
> this.
>
> I've a pile of used chainrings. Just as if I had a pile of used
> chains, I'd like to describe their wear. How to do it?
>
> I tried putting a 5 inch length of new SRAM PC58 chain on each ring,
> holding down the last links and pulling up; also moving the length of
> chain around the rings. For comparison with used chainrings I had 3
> new rings. A circa-1995 Campagnolo 53t ring and a new 1985 Takagi 52t.
> Both rings were ground and should represent quality machining. I also
> had a new old stock 52 t 144bcd ring by ???
>
> Aside from visually obvious wear to the face of the teeth of some used
> rings, I could not say that the movement of the chainon the used
> chains differentiated them from the movement on the new ones. There
> was as much difference between the new chainrings as there was between
> new and used.
>
> This isn't academic if I'd like to predict how the ring will perform,
> for me or someone else, or if I'd like to be sure the ring will not
> excessively wear or damage a new chain, and then cassette sprockets.
>
> So what is the metric, besides "chain skips on it under load" and
> "teeth look hooked?

Yes, it's hard to evaluate chainring wear! A new chain will generally
run acceptably well on old rings but shift response may suffer. The
teeth have to be down to ugly little stumps before you get actual
failure. That limit is a smaller stump on big rings than on small rings
because fewer teeth engage on small rings. (32t and 36t triple middle
rings being the most commonly replaced 'worn out' sizes)
Definitive overview here:
http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html

short answer: No definitive measurable limit off the bike.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

[Paul Kopit]

On Wed, 26 Mar 2008 20:27:42 -0700 (PDT), "travis.harry@gmail.com"
<travis.harry@gmail.com> wrote:

>So what is the metric, besides "chain skips on it under load" and
>"teeth look hooked?

With 50/34 combinations, the chain will miss the 34 on a downshift
when the 50 is worn.

With the bicycle on the stand have the chain on the big ring and the
2nd largest cog. Downshift the front derailleur. Then slowly move
the crank. You will see that the chain begins to engage the 34 before
it is completely off the 50. If the chain hangs onto the 50 a bit too
long, it will miss the inner ring and you'll drop the chain.

[DNM]

On Mar 27, 1:09*am, A Muzi <a...@yellowjersey.org> wrote:
> travis.ha...@gmail.com wrote:
> > I've spent hours searching in groups. Maybe there's a NEW approach to
> > this.
>
> > I've a pile of used chainrings. Just as if I had a pile of used
> > chains, I'd like to describe their wear. How to do it?
>
> > I tried putting a 5 inch length of new SRAM PC58 chain on each ring,
> > holding down the last links and pulling up; also moving the length of
> > chain around the rings. For comparison with used chainrings I had 3
> > new rings. A circa-1995 Campagnolo 53t ring and a new 1985 Takagi 52t.
> > Both rings were ground and should represent quality machining. I also
> > had a new old stock 52 t 144bcd ring by ???
>
> > Aside from visually obvious wear to the face of the teeth of some used
> > rings, I could not say that the movement of the chainon the used
> > chains differentiated them from the movement on the new ones. There
> > was as much difference between the new chainrings as there was between
> > new and used.
>
> > This isn't academic if I'd like to predict how the ring will perform,
> > for me or someone else, or if I'd like to be sure the ring will not
> > excessively wear or damage a new chain, and then cassette sprockets.
>
> > So what is the metric, besides "chain skips on it under load" and
> > "teeth look hooked?
>
> Yes, it's hard to evaluate chainring wear! A new chain will generally
> run acceptably well on old rings but shift response may suffer. The
> teeth have to be down to ugly little stumps before you get actual
> failure. *That limit is a smaller stump on big rings than on small rings
> because fewer teeth engage on small rings. (32t and 36t triple middle
> rings being the most commonly replaced 'worn out' sizes)
> Definitive overview here:http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html
>
> short answer: No definitive measurable limit off the bike.
> --
> Andrew Muziwww.yellowjersey.org
> Open every day since 1 April, 1971

But, realistically, if one uses Campy or Shimano chains that have no
easy-to-break links, removing a chain to lube this days is quite
difficult. I clean my chains on the bike, use Pro-Link lube, and
change my chains once per year or so and they are not beyond 1/16" in
12" by that time (i.e. almost no wear in 5000 miles). I do join my
chains with a removable KMC missing-Link, but that is a one-time use
link and I generally leave the chain on the bike for its life.

What do others use and do you still remove the chain to clean it?

[travis.harry@gmail.com]

On Mar 27, 1:09 am, A Muzi <a...@yellowjersey.org> wrote:
> travis.ha...@gmail.com wrote:
> > I've spent hours searching in groups. Maybe there's a NEW approach to
> > this.
>
> > I've a pile of used chainrings. Just as if I had a pile of used
> > chains, I'd like to describe their wear. How to do it?
>
> > I tried putting a 5 inch length of new SRAM PC58 chain on each ring,
> > holding down the last links and pulling up; also moving the length of
> > chain around the rings. For comparison with used chainrings I had 3
> > new rings. A circa-1995 Campagnolo 53t ring and a new 1985 Takagi 52t.
> > Both rings were ground and should represent quality machining. I also
> > had a new old stock 52 t 144bcd ring by ???
>
> > Aside from visually obvious wear to the face of the teeth of some used
> > rings, I could not say that the movement of the chainon the used
> > chains differentiated them from the movement on the new ones. There
> > was as much difference between the new chainrings as there was between
> > new and used.
>
> > This isn't academic if I'd like to predict how the ring will perform,
> > for me or someone else, or if I'd like to be sure the ring will not
> > excessively wear or damage a new chain, and then cassette sprockets.
>
> > So what is the metric, besides "chain skips on it under load" and
> > "teeth look hooked?
>
> Yes, it's hard to evaluate chainring wear! A new chain will generally
> run acceptably well on old rings but shift response may suffer. The
> teeth have to be down to ugly little stumps before you get actual
> failure. That limit is a smaller stump on big rings than on small rings
> because fewer teeth engage on small rings. (32t and 36t triple middle
> rings being the most commonly replaced 'worn out' sizes)
> Definitive overview here:http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html
>
> short answer: No definitive measurable limit off the bike.
> --
> Andrew Muziwww.yellowjersey.org
> Open every day since 1 April, 1971

Thanks, Andrew. Your answers always pithy; Jobst's so .....

Anyway, Jobst doesn't get around to saying in the FAQ whether a worn
chainring accelerates wear on the chain, new or old. Does it? If not,
it would seem there's not much reason, except for looks, crisper
shifting and the LBS's wrench's respecct , to ever change the big ring
on, a commuter bike or a tourer. Chainsuck with a lubed chain on a
big ring just never happens, does it?

Harry Travis

[Tom Sherman]

Andrew Muzi wrote:
> travis.harry@gmail.com wrote:
>> I've spent hours searching in groups. Maybe there's a NEW approach to
>> this.
>>
>> I've a pile of used chainrings. Just as if I had a pile of used
>> chains, I'd like to describe their wear. How to do it?
>>
>> I tried putting a 5 inch length of new SRAM PC58 chain on each ring,
>> holding down the last links and pulling up; also moving the length of
>> chain around the rings. For comparison with used chainrings I had 3
>> new rings. A circa-1995 Campagnolo 53t ring and a new 1985 Takagi 52t.
>> Both rings were ground and should represent quality machining. I also
>> had a new old stock 52 t 144bcd ring by ???
>>
>> Aside from visually obvious wear to the face of the teeth of some used
>> rings, I could not say that the movement of the chainon the used
>> chains differentiated them from the movement on the new ones. There
>> was as much difference between the new chainrings as there was between
>> new and used.
>>
>> This isn't academic if I'd like to predict how the ring will perform,
>> for me or someone else, or if I'd like to be sure the ring will not
>> excessively wear or damage a new chain, and then cassette sprockets.
>>
>> So what is the metric, besides "chain skips on it under load" and
>> "teeth look hooked?
>
> Yes, it's hard to evaluate chainring wear! A new chain will generally
> run acceptably well on old rings but shift response may suffer. The
> teeth have to be down to ugly little stumps before you get actual
> failure. That limit is a smaller stump on big rings than on small rings
> because fewer teeth engage on small rings. (32t and 36t triple middle
> rings being the most commonly replaced 'worn out' sizes)
> Definitive overview here:
> http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html
>
> short answer: No definitive measurable limit off the bike.

So how does the professional bicycle mechanic decide when to recommend
new chainrings [1] to the customer?

[1] Or is a new crank with rings included less expensive?

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

[A Muzi]

>> travis.ha...@gmail.com wrote:
>>> I've spent hours searching in groups. Maybe there's a NEW approach to
>>> this.
>>> I've a pile of used chainrings. Just as if I had a pile of used
>>> chains, I'd like to describe their wear. How to do it?
>>> I tried putting a 5 inch length of new SRAM PC58 chain on each ring,
>>> holding down the last links and pulling up; also moving the length of
>>> chain around the rings. For comparison with used chainrings I had 3
>>> new rings. A circa-1995 Campagnolo 53t ring and a new 1985 Takagi 52t.
>>> Both rings were ground and should represent quality machining. I also
>>> had a new old stock 52 t 144bcd ring by ???
>>> Aside from visually obvious wear to the face of the teeth of some used
>>> rings, I could not say that the movement of the chainon the used
>>> chains differentiated them from the movement on the new ones. There
>>> was as much difference between the new chainrings as there was between
>>> new and used.
>>> This isn't academic if I'd like to predict how the ring will perform,
>>> for me or someone else, or if I'd like to be sure the ring will not
>>> excessively wear or damage a new chain, and then cassette sprockets.
>>> So what is the metric, besides "chain skips on it under load" and
>>> "teeth look hooked?

> A Muzi <a...@yellowjersey.org> wrote:
>> Yes, it's hard to evaluate chainring wear! A new chain will generally
>> run acceptably well on old rings but shift response may suffer. The
>> teeth have to be down to ugly little stumps before you get actual
>> failure. That limit is a smaller stump on big rings than on small rings
>> because fewer teeth engage on small rings. (32t and 36t triple middle
>> rings being the most commonly replaced 'worn out' sizes)
>> Definitive overview here:http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html
>> short answer: No definitive measurable limit off the bike.

DNM wrote:
> But, realistically, if one uses Campy or Shimano chains that have no
> easy-to-break links, removing a chain to lube this days is quite
> difficult. I clean my chains on the bike, use Pro-Link lube, and
> change my chains once per year or so and they are not beyond 1/16" in
> 12" by that time (i.e. almost no wear in 5000 miles). I do join my
> chains with a removable KMC missing-Link, but that is a one-time use
> link and I generally leave the chain on the bike for its life.
> What do others use and do you still remove the chain to clean it?

We think KMC's 'one time use' admonishment is overstated.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

[Michael Press]

In article
<851f404e-fe29-43b0-837c-cc7cc84d49a5@e60g2000hsh.googlegroups.com>,
DNM <dnmakinson@gmail.com> wrote:

> On Mar 27, 1:09*am, A Muzi <a...@yellowjersey.org> wrote:
> > travis.ha...@gmail.com wrote:
> > > I've spent hours searching in groups. Maybe there's a NEW approach to
> > > this.
> >
> > > I've a pile of used chainrings. Just as if I had a pile of used
> > > chains, I'd like to describe their wear. How to do it?
> >
> > > I tried putting a 5 inch length of new SRAM PC58 chain on each ring,
> > > holding down the last links and pulling up; also moving the length of
> > > chain around the rings. For comparison with used chainrings I had 3
> > > new rings. A circa-1995 Campagnolo 53t ring and a new 1985 Takagi 52t.
> > > Both rings were ground and should represent quality machining. I also
> > > had a new old stock 52 t 144bcd ring by ???
> >
> > > Aside from visually obvious wear to the face of the teeth of some used
> > > rings, I could not say that the movement of the chainon the used
> > > chains differentiated them from the movement on the new ones. There
> > > was as much difference between the new chainrings as there was between
> > > new and used.
> >
> > > This isn't academic if I'd like to predict how the ring will perform,
> > > for me or someone else, or if I'd like to be sure the ring will not
> > > excessively wear or damage a new chain, and then cassette sprockets.
> >
> > > So what is the metric, besides "chain skips on it under load" and
> > > "teeth look hooked?
> >
> > Yes, it's hard to evaluate chainring wear! A new chain will generally
> > run acceptably well on old rings but shift response may suffer. The
> > teeth have to be down to ugly little stumps before you get actual
> > failure. *That limit is a smaller stump on big rings than on small rings
> > because fewer teeth engage on small rings. (32t and 36t triple middle
> > rings being the most commonly replaced 'worn out' sizes)
> > Definitive overview here:http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html
> >
> > short answer: No definitive measurable limit off the bike.
>
> But, realistically, if one uses Campy or Shimano chains that have no
> easy-to-break links, removing a chain to lube this days is quite
> difficult. I clean my chains on the bike, use Pro-Link lube, and
> change my chains once per year or so and they are not beyond 1/16" in
> 12" by that time (i.e. almost no wear in 5000 miles). I do join my
> chains with a removable KMC missing-Link, but that is a one-time use
> link and I generally leave the chain on the bike for its life.
>
> What do others use and do you still remove the chain to clean it?

I leave it on the bicycle.
Wipe the chain regularly.
Occasionally I clean and lubricate with Rock and Roll
using their instructions.

--
Michael Press

[peter]

On Mar 27, 8:24 am, "travis.ha...@gmail.com" <travis.ha...@gmail.com>
wrote:

> Anyway, Jobst doesn't get around to saying in the FAQ whether a worn
> chainring accelerates wear on the chain, new or old. Does it? If not,
> it would seem there's not much reason, except for looks, crisper
> shifting and the LBS's wrench's respecct , to ever change the big ring
> on, a commuter bike or a tourer. Chainsuck with a lubed chain on a
> big ring just never happens, does it?

I had to flip the big (52T) ring over on my bike about 20 kmiles ago
when the chain started to skip on it under load. It's been working ok
so far wih the chain applying pressure on the other side of the teeth
but I expect that within another year or two it'll start skipping
again and need to be replaced.

[Dan Burkhart]

A Muzi Wrote:
> >> travis.ha...@gmail.com wrote:
> >>> I've spent hours searching in groups. Maybe there's a NEW approach
> to
> >>> this.
> >>> I've a pile of used chainrings. Just as if I had a pile of used
> >>> chains, I'd like to describe their wear. How to do it?
> >>> I tried putting a 5 inch length of new SRAM PC58 chain on each
> ring,
> >>> holding down the last links and pulling up; also moving the length
> of
> >>> chain around the rings. For comparison with used chainrings I had
> 3
> >>> new rings. A circa-1995 Campagnolo 53t ring and a new 1985 Takagi
> 52t.
> >>> Both rings were ground and should represent quality machining. I
> also
> >>> had a new old stock 52 t 144bcd ring by ???
> >>> Aside from visually obvious wear to the face of the teeth of some
> used
> >>> rings, I could not say that the movement of the chainon the used
> >>> chains differentiated them from the movement on the new ones.
> There
> >>> was as much difference between the new chainrings as there was
> between
> >>> new and used.
> >>> This isn't academic if I'd like to predict how the ring will
> perform,
> >>> for me or someone else, or if I'd like to be sure the ring will
> not
> >>> excessively wear or damage a new chain, and then cassette
> sprockets.
> >>> So what is the metric, besides "chain skips on it under load" and
> >>> "teeth look hooked?
>
> > A Muzi <a...@yellowjersey.org> wrote:
> >> Yes, it's hard to evaluate chainring wear! A new chain will
> generally
> >> run acceptably well on old rings but shift response may suffer. The
> >> teeth have to be down to ugly little stumps before you get actual
> >> failure. That limit is a smaller stump on big rings than on small
> rings
> >> because fewer teeth engage on small rings. (32t and 36t triple
> middle
> >> rings being the most commonly replaced 'worn out' sizes)
> >> Definitive overview
> here:http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html
> >> short answer: No definitive measurable limit off the bike.
>
> DNM wrote:
> > But, realistically, if one uses Campy or Shimano chains that have no
> > easy-to-break links, removing a chain to lube this days is quite
> > difficult. I clean my chains on the bike, use Pro-Link lube, and
> > change my chains once per year or so and they are not beyond 1/16"
> in
> > 12" by that time (i.e. almost no wear in 5000 miles). I do join my
> > chains with a removable KMC missing-Link, but that is a one-time use
> > link and I generally leave the chain on the bike for its life.
> > What do others use and do you still remove the chain to clean it?
>
> We think KMC's 'one time use' admonishment is overstated.
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
Yup. Re-use em all the time. No issues.


--
Dan Burkhart

[A Muzi]

>> travis.harry@gmail.com wrote:
>>> I've spent hours searching in groups. Maybe there's a NEW approach to
>>> this.
>>>
>>> I've a pile of used chainrings. Just as if I had a pile of used
>>> chains, I'd like to describe their wear. How to do it?
>>>
>>> I tried putting a 5 inch length of new SRAM PC58 chain on each ring,
>>> holding down the last links and pulling up; also moving the length of
>>> chain around the rings. For comparison with used chainrings I had 3
>>> new rings. A circa-1995 Campagnolo 53t ring and a new 1985 Takagi 52t.
>>> Both rings were ground and should represent quality machining. I also
>>> had a new old stock 52 t 144bcd ring by ???
>>>
>>> Aside from visually obvious wear to the face of the teeth of some used
>>> rings, I could not say that the movement of the chainon the used
>>> chains differentiated them from the movement on the new ones. There
>>> was as much difference between the new chainrings as there was between
>>> new and used.
>>>
>>> This isn't academic if I'd like to predict how the ring will perform,
>>> for me or someone else, or if I'd like to be sure the ring will not
>>> excessively wear or damage a new chain, and then cassette sprockets.
>>>
>>> So what is the metric, besides "chain skips on it under load" and
>>> "teeth look hooked?

> Andrew Muzi wrote:
>> Yes, it's hard to evaluate chainring wear! A new chain will generally
>> run acceptably well on old rings but shift response may suffer. The
>> teeth have to be down to ugly little stumps before you get actual
>> failure. That limit is a smaller stump on big rings than on small
>> rings because fewer teeth engage on small rings. (32t and 36t triple
>> middle rings being the most commonly replaced 'worn out' sizes)
>> Definitive overview here:
>> http://draco.acs.uci.edu/rbfaq/FAQ/8d.2.html
>> short answer: No definitive measurable limit off the bike.

Tom Sherman wrote:
> So how does the professional bicycle mechanic decide when to recommend
> new chainrings [1] to the customer?
> [1] Or is a new crank with rings included less expensive?

There are indeed cases where 2 or 3 rings on an older crank cost more
than a complete current model crank set (complete cranks are a zero-duty
item for some reason; other factors come into play as well).

We normally replace chainrings after customer report of wear symptoms as
we cannot see that they are dysfunctional except in extreme cases.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

[Donald Gillies]

A Muzi <am@yellowjersey.org> writes:

>Tom Sherman wrote:
>> So how does the professional bicycle mechanic decide when to recommend
>> new chainrings [1] to the customer?
>> [1] Or is a new crank with rings included less expensive?

>There are indeed cases where 2 or 3 rings on an older crank cost more
>than a complete current model crank set (complete cranks are a zero-duty
>item for some reason; other factors come into play as well).

>We normally replace chainrings after customer report of wear symptoms as
>we cannot see that they are dysfunctional except in extreme cases.
>--
>Andrew Muzi
>www.yellowjersey.org
>Open every day since 1 April, 1971

http://i20.ebayimg.com/04/i/000/e6/06/5cd8_1.JPG

Here are some chainrings on Ebay that are probably 'at least' 70%
gone.

Some signs of severe wear are (a) Chamfering has worn away from the
sides of each tooth, ( see http://en.wikipedia.org/wiki/Chamfer ) (b)
between each tooth, it looks more like a "U" than a semicircle, and
(c) the slope of the space between each tooth looks like \_|, not |_|,
i.e. the teeth are 'leaning back' on one side only.

The width of each tooth is really how we should measure chain wear.

- Don Gillies
San Diego, CA