Are KMC-Z chains directional?

On Saturday, March 6, 2021 at 6:02:57 PM UTC-5, wrote:
Op zaterdag 6 maart 2021 om 22:53:55 UTC+1 schreef Frank Krygowski:
On 3/6/2021 3:43 PM, Lou Holtman wrote:
Op zaterdag 6 maart 2021 om 01:48:31 UTC+1 schreef Mark J.:
On 3/5/2021 10:07 AM, Frank Krygowski wrote:
On 3/4/2021 9:34 PM, James wrote:
On 5/3/21 1:00 pm, Frank Krygowski wrote:
On 3/4/2021 6:16 PM, James wrote:
On 5/3/21 9:02 am, AMuzi wrote:
On 3/4/2021 4:00 PM, AMuzi wrote:
On 3/4/2021 3:15 PM, James wrote:
On 4/3/21 1:16 pm, Jeff Liebermann wrote:
On Wed, 3 Mar 2021 15:47:52 -0800, Joerg

wrote:

My last Shimano chain is worn so I'll be trying the first
KMC-Z72
8-speed chain on my road bike next week, since Jay
recommended those.
Are they directional? The package doesn't say and the
Internet doesn't
either.

This article doesn't mention KMC, but does mention that
SRAM chains
are not directional, while some Shimano chains are
directional. The
article suggests that directional chains have the logo
stamped only on
one side of the chain, which should be facing away from
the frame:

Are Bicycle Chains directional?
https://bikesfaq.com/are-bicycle-chains-directional-some-are-some-arent




I couldn't find a data sheet on the KMC Z-72. Everywhere
I look, all
I find are "discontinued" or "otto stock" (except some old
stock on
eBay).


According to that web page;

"What happens if you put it on the wrong way?

It does not impact brand new chains’ performance if you do
inadvertently put the chain in the “wrong†direction.
Perhaps on really high-end chains and groupsets, it may have
a marginal impact on efficiency or lifespan; however, for
most cyclists, you will not notice any drop in performance
or skipping of gears.

If you are taking off an existing chain to clean it and put
it back on, you must put it back in the same direction as it
was before.

Due to wear and tear, failure to replace the chain how it
was before will result in the chain and gears slipping."


Does anyone know why they think that the chain and gears
might slip as described in the last sentence?


Chain wear is between rivet and roller. Presumably rivets
wear on the front side while rollers roll.


Whoops. Rivet is driven so wear would be on the back side not
front. Sorry.


Looking at a section of Campagnolo chain and assuming KMC Z 72
chains are constructed similarly, the pin doesn't touch the roller.
The chain acts in tension whether it is upside down or right side
up, so the pin wear against the inner plates is always the same.
Because the roller can roll right around, how does it know which way
is up? Chain elongation happens as the pins and inner plates wear,
and measures the same regardless of whether you stand on your head
or not.

Clearly I still do not understand the reason.

I don't know for sure, but I suspect the problem is this: The wear on
the chain's internals is not symmetrical. It mostly occurs as the
chain leaves a small rear cog. The tension puts loads on the surfaces
as each chain link pivots from bent to straight.

That pivoting is always in the same direction, so the wear is
primarily on the mating surfaces below the centerline of the taut
upper chain - that is, toward the center of the chain's loop. The
portions of the pin and (integral) bushing above the centerline wear
much less. And as the chain wears, it tends to wear the cog teeth to
match its gradually longer pitch.

If you change the chain orientation, you're exposing new portions of
those internal surfaces to wear. Since they haven't yet worn as much,
the effective pitch is less at the moments the links are on the cog.
That gives a pitch mismatch that causes the skipping.

That's my guess.

A corollary might be that flipping a non-directional chain from time
to time might might extend the life of the chain and cogs, somewhat
similar to alternating two or three chains on the same cogs. But I'll
never be curious enough to bother trying that.


Perhaps you're right about the asymmetric wear, but that doesn't
explain why some chains are deemed directional.

I think the main idea of directional chains is to aid shifting a bit, by
shaping the side plates so they ease the jump to a larger cog. I don't
know the details, though; I ride old technology.

I would have thought so also, but I just installed a new Shimano 105
11-speed chain. In the directions were clear indications of how to
install (chain plates with logos to face *away* from the frame.)

I looked at the side plates on both sides, expecting different shaping
on the two sides. I sure couldn't see any difference.

Mark J.

I took the chain of one of my bikes (Shimano HG701, 11 speed Ultegra/XT level 11) and took a photo of both outer plates and one can see the subtle difference:

https://photos.app.goo.gl/vf87tgeyooGy1PYQ9
https://photos.app.goo.gl/aqNX91mwFZwqUUQW7

I also have a spare 11 speed 105 (HG601) and this one also has the same different outer plates.
So it's almost microscopic differences in chamfers on the two sides? No
other differences?

It is what it is. Mark didn't see any difference. He didn't looked close enough. What did you expect BTW?

I didn't know, Lou. I thought that the side plates might have been bulged outward on one edge
or another. I was just asking.

You often seem very touchy.

- Frank Krygowski

On Sunday, March 7, 2021 at 2:04:33 AM UTC, wrote:
On Saturday, March 6, 2021 at 6:02:57 PM UTC-5, wrote:

So it's almost microscopic differences in chamfers on the two sides? No
other differences?

It is what it is. Mark didn't see any difference. He didn't looked close enough. What did you expect BTW?
I didn't know, Lou. I thought that the side plates might have been bulged outward on one edge
or another. I was just asking.

You often seem very touchy.

- Frank Krygowski
..
Anyone would, Franki-boy, when faced with your bullying barrage of hostile, biased questions. Doesn't matter anymore whether you rarely try to be polite, people expect you to be an asshole -- and react accordingly. I can't say I feel sorry for you: you did it to yourself.

Andre Jute
Just thought I'd mention it.

Op zondag 7 maart 2021 om 03:04:33 UTC+1 schreef :
On Saturday, March 6, 2021 at 6:02:57 PM UTC-5, wrote:
Op zaterdag 6 maart 2021 om 22:53:55 UTC+1 schreef Frank Krygowski:
On 3/6/2021 3:43 PM, Lou Holtman wrote:
Op zaterdag 6 maart 2021 om 01:48:31 UTC+1 schreef Mark J.:
On 3/5/2021 10:07 AM, Frank Krygowski wrote:
On 3/4/2021 9:34 PM, James wrote:
On 5/3/21 1:00 pm, Frank Krygowski wrote:
On 3/4/2021 6:16 PM, James wrote:
On 5/3/21 9:02 am, AMuzi wrote:
On 3/4/2021 4:00 PM, AMuzi wrote:
On 3/4/2021 3:15 PM, James wrote:
On 4/3/21 1:16 pm, Jeff Liebermann wrote:
On Wed, 3 Mar 2021 15:47:52 -0800, Joerg

wrote:

My last Shimano chain is worn so I'll be trying the first
KMC-Z72
8-speed chain on my road bike next week, since Jay
recommended those.
Are they directional? The package doesn't say and the
Internet doesn't
either.

This article doesn't mention KMC, but does mention that
SRAM chains
are not directional, while some Shimano chains are
directional. The
article suggests that directional chains have the logo
stamped only on
one side of the chain, which should be facing away from
the frame:

Are Bicycle Chains directional?
https://bikesfaq.com/are-bicycle-chains-directional-some-are-some-arent




I couldn't find a data sheet on the KMC Z-72. Everywhere
I look, all
I find are "discontinued" or "otto stock" (except some old
stock on
eBay).


According to that web page;

"What happens if you put it on the wrong way?

It does not impact brand new chains’ performance if you do
inadvertently put the chain in the “wrong†direction.
Perhaps on really high-end chains and groupsets, it may have
a marginal impact on efficiency or lifespan; however, for
most cyclists, you will not notice any drop in performance
or skipping of gears.

If you are taking off an existing chain to clean it and put
it back on, you must put it back in the same direction as it
was before.

Due to wear and tear, failure to replace the chain how it
was before will result in the chain and gears slipping."


Does anyone know why they think that the chain and gears
might slip as described in the last sentence?


Chain wear is between rivet and roller. Presumably rivets
wear on the front side while rollers roll.


Whoops. Rivet is driven so wear would be on the back side not
front. Sorry.


Looking at a section of Campagnolo chain and assuming KMC Z 72
chains are constructed similarly, the pin doesn't touch the roller.
The chain acts in tension whether it is upside down or right side
up, so the pin wear against the inner plates is always the same.
Because the roller can roll right around, how does it know which way
is up? Chain elongation happens as the pins and inner plates wear,
and measures the same regardless of whether you stand on your head
or not.

Clearly I still do not understand the reason.

I don't know for sure, but I suspect the problem is this: The wear on
the chain's internals is not symmetrical. It mostly occurs as the
chain leaves a small rear cog. The tension puts loads on the surfaces
as each chain link pivots from bent to straight.

That pivoting is always in the same direction, so the wear is
primarily on the mating surfaces below the centerline of the taut
upper chain - that is, toward the center of the chain's loop. The
portions of the pin and (integral) bushing above the centerline wear
much less. And as the chain wears, it tends to wear the cog teeth to
match its gradually longer pitch.

If you change the chain orientation, you're exposing new portions of
those internal surfaces to wear. Since they haven't yet worn as much,
the effective pitch is less at the moments the links are on the cog.
That gives a pitch mismatch that causes the skipping.

That's my guess.

A corollary might be that flipping a non-directional chain from time
to time might might extend the life of the chain and cogs, somewhat
similar to alternating two or three chains on the same cogs. But I'll
never be curious enough to bother trying that.


Perhaps you're right about the asymmetric wear, but that doesn't
explain why some chains are deemed directional.

I think the main idea of directional chains is to aid shifting a bit, by
shaping the side plates so they ease the jump to a larger cog. I don't
know the details, though; I ride old technology.

I would have thought so also, but I just installed a new Shimano 105
11-speed chain. In the directions were clear indications of how to
install (chain plates with logos to face *away* from the frame.)

I looked at the side plates on both sides, expecting different shaping
on the two sides. I sure couldn't see any difference.

Mark J.

I took the chain of one of my bikes (Shimano HG701, 11 speed Ultegra/XT level 11) and took a photo of both outer plates and one can see the subtle difference:

https://photos.app.goo.gl/vf87tgeyooGy1PYQ9
https://photos.app.goo.gl/aqNX91mwFZwqUUQW7

I also have a spare 11 speed 105 (HG601) and this one also has the same different outer plates.
So it's almost microscopic differences in chamfers on the two sides? No
other differences?

It is what it is. Mark didn't see any difference. He didn't looked close enough. What did you expect BTW?
I didn't know, Lou. I thought that the side plates might have been bulged outward on one edge
or another. I was just asking.

You often seem very touchy.


One could interpret 'microscopic differences in chamfers' as biased but I didn't. I reread my answer and I could not see any touchiness. I gave an honest answer to the OP, provided photo's, shared my experience and even my opinion. You carry on discussing whether an aluminum rim is extruded, casted or molded after the question/unclarity is long answered/cleared up. I won't bother you (or Tom).

Lou,
If you are able to watch the coverage of the Strade Bianca 2021 I recommend it.

On Saturday, March 6, 2021 at 3:02:57 PM UTC-8, wrote:
Op zaterdag 6 maart 2021 om 22:53:55 UTC+1 schreef Frank Krygowski:
On 3/6/2021 3:43 PM, Lou Holtman wrote:
Op zaterdag 6 maart 2021 om 01:48:31 UTC+1 schreef Mark J.:
On 3/5/2021 10:07 AM, Frank Krygowski wrote:
On 3/4/2021 9:34 PM, James wrote:
On 5/3/21 1:00 pm, Frank Krygowski wrote:
On 3/4/2021 6:16 PM, James wrote:
On 5/3/21 9:02 am, AMuzi wrote:
On 3/4/2021 4:00 PM, AMuzi wrote:
On 3/4/2021 3:15 PM, James wrote:
On 4/3/21 1:16 pm, Jeff Liebermann wrote:
On Wed, 3 Mar 2021 15:47:52 -0800, Joerg

wrote:

My last Shimano chain is worn so I'll be trying the first
KMC-Z72
8-speed chain on my road bike next week, since Jay
recommended those.
Are they directional? The package doesn't say and the
Internet doesn't
either.

This article doesn't mention KMC, but does mention that
SRAM chains
are not directional, while some Shimano chains are
directional. The
article suggests that directional chains have the logo
stamped only on
one side of the chain, which should be facing away from
the frame:

Are Bicycle Chains directional?
https://bikesfaq.com/are-bicycle-chains-directional-some-are-some-arent




I couldn't find a data sheet on the KMC Z-72. Everywhere
I look, all
I find are "discontinued" or "otto stock" (except some old
stock on
eBay).


According to that web page;

"What happens if you put it on the wrong way?

It does not impact brand new chains’ performance if you do
inadvertently put the chain in the “wrong†direction.
Perhaps on really high-end chains and groupsets, it may have
a marginal impact on efficiency or lifespan; however, for
most cyclists, you will not notice any drop in performance
or skipping of gears.

If you are taking off an existing chain to clean it and put
it back on, you must put it back in the same direction as it
was before.

Due to wear and tear, failure to replace the chain how it
was before will result in the chain and gears slipping."


Does anyone know why they think that the chain and gears
might slip as described in the last sentence?


Chain wear is between rivet and roller. Presumably rivets
wear on the front side while rollers roll.


Whoops. Rivet is driven so wear would be on the back side not
front. Sorry.


Looking at a section of Campagnolo chain and assuming KMC Z 72
chains are constructed similarly, the pin doesn't touch the roller.
The chain acts in tension whether it is upside down or right side
up, so the pin wear against the inner plates is always the same.
Because the roller can roll right around, how does it know which way
is up? Chain elongation happens as the pins and inner plates wear,
and measures the same regardless of whether you stand on your head
or not.

Clearly I still do not understand the reason.

I don't know for sure, but I suspect the problem is this: The wear on
the chain's internals is not symmetrical. It mostly occurs as the
chain leaves a small rear cog. The tension puts loads on the surfaces
as each chain link pivots from bent to straight.

That pivoting is always in the same direction, so the wear is
primarily on the mating surfaces below the centerline of the taut
upper chain - that is, toward the center of the chain's loop. The
portions of the pin and (integral) bushing above the centerline wear
much less. And as the chain wears, it tends to wear the cog teeth to
match its gradually longer pitch.

If you change the chain orientation, you're exposing new portions of
those internal surfaces to wear. Since they haven't yet worn as much,
the effective pitch is less at the moments the links are on the cog.
That gives a pitch mismatch that causes the skipping.

That's my guess.

A corollary might be that flipping a non-directional chain from time
to time might might extend the life of the chain and cogs, somewhat
similar to alternating two or three chains on the same cogs. But I'll
never be curious enough to bother trying that.


Perhaps you're right about the asymmetric wear, but that doesn't
explain why some chains are deemed directional.

I think the main idea of directional chains is to aid shifting a bit, by
shaping the side plates so they ease the jump to a larger cog. I don't
know the details, though; I ride old technology.

I would have thought so also, but I just installed a new Shimano 105
11-speed chain. In the directions were clear indications of how to
install (chain plates with logos to face *away* from the frame.)

I looked at the side plates on both sides, expecting different shaping
on the two sides. I sure couldn't see any difference.

Mark J.

I took the chain of one of my bikes (Shimano HG701, 11 speed Ultegra/XT level 11) and took a photo of both outer plates and one can see the subtle difference:

https://photos.app.goo.gl/vf87tgeyooGy1PYQ9
https://photos.app.goo.gl/aqNX91mwFZwqUUQW7

I also have a spare 11 speed 105 (HG601) and this one also has the same different outer plates.
So it's almost microscopic differences in chamfers on the two sides? No
other differences?

It is what it is. Mark didn't see any difference. He didn't looked close enough. What did you expect BTW? I don't know if it is the case here bu I know from experience that a little chamfer can make a big difference in many cases. If you mount the chain in the wrong orientation then it is noisier while shifting. If you mount the Shimano quick link in the wrong direction that link jumps up and down a tooth while backpedaling in the stand. All found out the hard way so I am not too fond of directional chains and quick links but if it is you better mount it the right way.

Lou
I have KMC gold 10 speed and it is perfectly symetrical.

On Saturday, March 6, 2021 at 8:54:35 PM UTC-8, Andre Jute wrote:
On Sunday, March 7, 2021 at 2:04:33 AM UTC, wrote:
On Saturday, March 6, 2021 at 6:02:57 PM UTC-5, wrote:

So it's almost microscopic differences in chamfers on the two sides? No
other differences?

It is what it is. Mark didn't see any difference. He didn't looked close enough. What did you expect BTW?
I didn't know, Lou. I thought that the side plates might have been bulged outward on one edge
or another. I was just asking.

You often seem very touchy.

- Frank Krygowski
.
Anyone would, Franki-boy, when faced with your bullying barrage of hostile, biased questions. Doesn't matter anymore whether you rarely try to be polite, people expect you to be an asshole -- and react accordingly. I can't say I feel sorry for you: you did it to yourself.

I think that it is his only source of attention.

On Saturday, March 6, 2021 at 3:13:34 PM UTC-8, Bertrand wrote:
I took the chain of one of my bikes (Shimano HG701, 11 speed Ultegra/XT level
11) and took a photo of both outer plates and one can see the subtle difference:

https://photos.app.goo.gl/vf87tgeyooGy1PYQ9
https://photos.app.goo.gl/aqNX91mwFZwqUUQW7

I also have a spare 11 speed 105 (HG601) and this one also has the same
different outer plates.

So it's almost microscopic differences in chamfers on the two sides? No other
differences?
On the 10-speed Shimano CN-6701 (Ultegra) chains that I use, it looks like the
outer plates are symmetrical. You can see here that some plates are oriented
with the lettering up, and some are down:

https://i.ebayimg.com/images/g/jfsAA...RK/s-l1600.jpg

But Shimano's instructions:

https://si.shimano.com/pdfs/si/SI-09R0A-002-ENG.pdf

do specify a direction: "we strongly recommend to set the connecting pin in the
hole of the outer link on the front side in the direction of travel".

That description is a little confusing, but Shimano's diagram makes it clear
that the chain should be installed so that the inner plates pull the connecting
pin. Shimano says that by doing it this way "The chain’s level of strength is
enhanced".
The early Ultegra chains had the pins and those sorts of instructions but they very rapidly changed to supplying quick links.

On 3/6/2021 12:43 PM, Lou Holtman wrote:
Op zaterdag 6 maart 2021 om 01:48:31 UTC+1 schreef Mark J.:
On 3/5/2021 10:07 AM, Frank Krygowski wrote:
On 3/4/2021 9:34 PM, James wrote:
On 5/3/21 1:00 pm, Frank Krygowski wrote:
On 3/4/2021 6:16 PM, James wrote:
On 5/3/21 9:02 am, AMuzi wrote:
On 3/4/2021 4:00 PM, AMuzi wrote:
On 3/4/2021 3:15 PM, James wrote:
On 4/3/21 1:16 pm, Jeff Liebermann wrote:
On Wed, 3 Mar 2021 15:47:52 -0800, Joerg

wrote:

My last Shimano chain is worn so I'll be trying the first
KMC-Z72
8-speed chain on my road bike next week, since Jay
recommended those.
Are they directional? The package doesn't say and the
Internet doesn't
either.

This article doesn't mention KMC, but does mention that
SRAM chains
are not directional, while some Shimano chains are
directional. The
article suggests that directional chains have the logo
stamped only on
one side of the chain, which should be facing away from
the frame:

Are Bicycle Chains directional?
https://bikesfaq.com/are-bicycle-chains-directional-some-are-some-arent




I couldn't find a data sheet on the KMC Z-72. Everywhere
I look, all
I find are "discontinued" or "otto stock" (except some old
stock on
eBay).


According to that web page;

"What happens if you put it on the wrong way?

It does not impact brand new chains’ performance if you do
inadvertently put the chain in the “wrong†direction.
Perhaps on really high-end chains and groupsets, it may have
a marginal impact on efficiency or lifespan; however, for
most cyclists, you will not notice any drop in performance
or skipping of gears.

If you are taking off an existing chain to clean it and put
it back on, you must put it back in the same direction as it
was before.

Due to wear and tear, failure to replace the chain how it
was before will result in the chain and gears slipping."


Does anyone know why they think that the chain and gears
might slip as described in the last sentence?


Chain wear is between rivet and roller. Presumably rivets
wear on the front side while rollers roll.


Whoops. Rivet is driven so wear would be on the back side not
front. Sorry.


Looking at a section of Campagnolo chain and assuming KMC Z 72
chains are constructed similarly, the pin doesn't touch the roller.
The chain acts in tension whether it is upside down or right side
up, so the pin wear against the inner plates is always the same.
Because the roller can roll right around, how does it know which way
is up? Chain elongation happens as the pins and inner plates wear,
and measures the same regardless of whether you stand on your head
or not.

Clearly I still do not understand the reason.

I don't know for sure, but I suspect the problem is this: The wear on
the chain's internals is not symmetrical. It mostly occurs as the
chain leaves a small rear cog. The tension puts loads on the surfaces
as each chain link pivots from bent to straight.

That pivoting is always in the same direction, so the wear is
primarily on the mating surfaces below the centerline of the taut
upper chain - that is, toward the center of the chain's loop. The
portions of the pin and (integral) bushing above the centerline wear
much less. And as the chain wears, it tends to wear the cog teeth to
match its gradually longer pitch.

If you change the chain orientation, you're exposing new portions of
those internal surfaces to wear. Since they haven't yet worn as much,
the effective pitch is less at the moments the links are on the cog.
That gives a pitch mismatch that causes the skipping.

That's my guess.

A corollary might be that flipping a non-directional chain from time
to time might might extend the life of the chain and cogs, somewhat
similar to alternating two or three chains on the same cogs. But I'll
never be curious enough to bother trying that.


Perhaps you're right about the asymmetric wear, but that doesn't
explain why some chains are deemed directional.

I think the main idea of directional chains is to aid shifting a bit, by
shaping the side plates so they ease the jump to a larger cog. I don't
know the details, though; I ride old technology.

I would have thought so also, but I just installed a new Shimano 105
11-speed chain. In the directions were clear indications of how to
install (chain plates with logos to face *away* from the frame.)

I looked at the side plates on both sides, expecting different shaping
on the two sides. I sure couldn't see any difference.

Mark J.

I took the chain of one of my bikes (Shimano HG701, 11 speed Ultegra/XT level 11) and took a photo of both outer plates and one can see the subtle difference:

https://photos.app.goo.gl/vf87tgeyooGy1PYQ9
https://photos.app.goo.gl/aqNX91mwFZwqUUQW7

I also have a spare 11 speed 105 (HG601) and this one also has the same different outer plates.

Lou

Thanks, I can see it now. I'll have to check to see if these
differences are present on the 105 chain.

Mark J.

On 3/5/21 9:27 AM, Tom Kunich wrote:
On Friday, March 5, 2021 at 7:15:36 AM UTC-8, AMuzi wrote:
On 3/4/2021 8:34 PM, James wrote:

[...]

Maybe the whole directional thing is because the chain
manufacturer likes their logo to be visible?

Directional wear and asymmetric (directional) design are two
different things:

https://www.sram.com/globalassets/im...del.jpg?w=1000

That gives me a much better idea of what we're talking about. I had gone out and looked at my top end chains and they had tooth engagement bevels only on one side but otherwise looked identical.


High-Tech!

It wouldn't likely matter for my stuff and I don't care about saving a
few milliseconds per shift. I sometimes even grind off part of the wider
spline and flip around a worn cog in the cassette to milk a few thousand
more miles out of it.

--
Regards, Joerg

http://www.analogconsultants.com/

On Monday, March 8, 2021 at 10:12:42 AM UTC-8, Joerg wrote:
On 3/5/21 9:27 AM, Tom Kunich wrote:
On Friday, March 5, 2021 at 7:15:36 AM UTC-8, AMuzi wrote:
On 3/4/2021 8:34 PM, James wrote:
[...]
Maybe the whole directional thing is because the chain
manufacturer likes their logo to be visible?

Directional wear and asymmetric (directional) design are two
different things:

https://www.sram.com/globalassets/im...del.jpg?w=1000

That gives me a much better idea of what we're talking about. I had gone out and looked at my top end chains and they had tooth engagement bevels only on one side but otherwise looked identical.

High-Tech!

It wouldn't likely matter for my stuff and I don't care about saving a
few milliseconds per shift. I sometimes even grind off part of the wider
spline and flip around a worn cog in the cassette to milk a few thousand
more miles out of it.

MY GOD Joerg, you're no bicycle aficionado at all!

On 3/8/21 11:04 AM, Tom Kunich wrote:
On Monday, March 8, 2021 at 10:12:42 AM UTC-8, Joerg wrote:
On 3/5/21 9:27 AM, Tom Kunich wrote:
On Friday, March 5, 2021 at 7:15:36 AM UTC-8, AMuzi wrote:
On 3/4/2021 8:34 PM, James wrote:
[...]
Maybe the whole directional thing is because the chain
manufacturer likes their logo to be visible?

Directional wear and asymmetric (directional) design are two
different things:

https://www.sram.com/globalassets/im...del.jpg?w=1000

That gives me a much better idea of what we're talking about. I had gone out and looked at my top end chains and they had tooth engagement bevels only on one side but otherwise looked identical.

High-Tech!

It wouldn't likely matter for my stuff and I don't care about saving a
few milliseconds per shift. I sometimes even grind off part of the wider
spline and flip around a worn cog in the cassette to milk a few thousand
more miles out of it.

MY GOD Joerg, you're no bicycle aficionado at all!


Yeah, to me bicycles are simply utility device. The hose clamp still
rides along, to keep the steerer from loosening too much.

http://www.analogconsultants.com/ng/bike/Hoseclamp.JPG

In Europe my Gazelle frame is often considered a classic and has fetched
prices north of $500 on EBay but ... mine is quite worn and when I had
my last rear tire blow-out I did the unthinkable. Fixed it with gauze
from my first aid kit.

http://www.analogconsultants.com/ng/bike/Gauze.JPG

Those 15mi with the gauze rubbed the chainstays bare on the insides but
it got me home. I took a can of gray Rustoleum that I had left over and
sprayed some of it onto the blue frame.

After the aluminum handlebar broke off (nasty crash) I affixed a MTB
straight bar from steel. My road bike also has MTB pedals which many
purists consider disgusting.

--
Regards, Joerg

http://www.analogconsultants.com/