Today I swapped out a normal crankset for a compact crankset,
and I had to shorten the chain by 2 links.
While I'm on the subject, there are some important points about chain cutting rules I should write about.
The two critical things about chain setup are:
「connecting with a fresh outer link」and
「the outer link faces the chainring side」
10-speed and higher chains have narrower widths = less material between the outer link and the pin for crimping.
To avoid chain breakage trouble,
we need to be extra careful these days.
Normally, chains ship with one end being an outer link
and the other end being an inner link.
This original end outer link is theoretically
the strongest when the connect pin is pressed in—
the pin and link crimping is at its strongest here.
This is the "fresh outer link."
If you cut the chain to length adjustment on the outer link side,
you'd be pressing the connect pin into an outer link that had its pin removed
(the hole might be enlarged).)
Theoretically, that's not ideal, so chain length adjustment
should be done on the inner link side.
I said "normally, chains ship with～" earlier, but
Shimano's CN-7800 has outer links on both ends,
so even if someone who doesn't know cuts the chain,
a fresh outer link is guaranteed to remain—it was designed that way.
For various reasons it was quickly replaced by the CN-7801, but
the CN-7801 and newer chains went back to having
an outer link on one end and an inner link on the other.
With Campagnolo chains,
a cable tie is attached to the fresh outer link at the end, and
it says very clearly: "don't cut from this side."
You can see how seriously they take the fresh outer link.
When I went back to my old workplace the other day, there was
a 6-link piece lying on the floor with the fresh outer link cut off, like in the image above.
Yeah, cutting that side saves you the trouble of using a chain tool!
Next, about link orientation.
If you casually connect the chain, the outer link will end up on either the
「chainring side」or the「rear derailleur side,」
but Shimano recommends the former (the state shown in the diagram above).
This is also a measure to avoid chain breakage as much as possible.
With Campagnolo, they don't state it in text, but
in the manual diagrams, they also show 「outer link on the chainring side,」
so that's what should be done.
With a new chain, this outer link must be a 「fresh outer link.」
These two points are the critical setup considerations for the chain.
So today I shortened the chain by 2 links (= 1 pitch),
and in the image above, the setup is chainring side outer link / rear derailleur side inner link,
with the connect pin joined—this is the correct state.
Before removing the chain pin, I marked
the chainring side with light blue and the rear derailleur side with white.
To remove one pitch, I remove the pins on both sides of the connect pin.
↑This leaves you in this state.
This would be the orientation Shimano doesn't recommend, so
I remove the chain from the bike and flip it front-to-back to reinstall it.
By doing this, the result looks like「one pitch shorter, but still just one connect pin」
In a chain readjustment, you can't connect with a fresh outer link anyway,
but I still think fewer connect pins is better.
This is how I do it when shortening Shimano chains.
The joined part of a chain is normally the part most prone to breaking.
With current Campagnolo 11-speed chain design, I think the joined part is actually strongest,
but in any case, manufacturers are struggling with the fact that narrower chains
have raised the risk of breakage.
If 12-speed or 13-speed components come out in the future,
the chain might be the most difficult component to manufacture.
Going off on a tangent, with 13-speed, an 11-23T would be
11・12・13・14・15・16・17・18・19・20・21・22・23—
with no gaps in tooth count.
If you then made an 11-25T by dropping the 22T and adding a 25T,
I bet pro racers wouldn't complain with just those two options.
Then if you offered 11-28T and 12-28T for amateurs,
they wouldn't have issues either.
13-speed might be the ultimate endpoint.
Though there are issues with rear axle spacing and chainline too.
Campagnolo once had a product called "Permalink"—
a replacement chain part where you'd swap out 7-link sections with fresh outer links on both ends.
By including a connect pin link in the discarded section,
you keep the number of connect pins from increasing unnecessarily, and
any connect pin pressed in is guaranteed to be on a fresh outer link—that was the idea.
You could adjust length by using 5-link or 9-link sections to discard.
This is an example of how much component makers care about chain breakage problems.
If you work on your own bikes, try to be conscious of the 「fresh outer link」
when adjusting your chain.
With a non-fresh outer link, the connect pin tends not to go in straight,
and the crimping can deform the outer link's hole.
and I had to shorten the chain by 2 links.
While I'm on the subject, there are some important points about chain cutting rules I should write about.
The two critical things about chain setup are:
「connecting with a fresh outer link」and
「the outer link faces the chainring side」
10-speed and higher chains have narrower widths = less material between the outer link and the pin for crimping.
To avoid chain breakage trouble,
we need to be extra careful these days.
Normally, chains ship with one end being an outer link
and the other end being an inner link.
This original end outer link is theoretically
the strongest when the connect pin is pressed in—
the pin and link crimping is at its strongest here.
This is the "fresh outer link."
If you cut the chain to length adjustment on the outer link side,
you'd be pressing the connect pin into an outer link that had its pin removed
(the hole might be enlarged).)
Theoretically, that's not ideal, so chain length adjustment
should be done on the inner link side.
I said "normally, chains ship with～" earlier, but
Shimano's CN-7800 has outer links on both ends,
so even if someone who doesn't know cuts the chain,
a fresh outer link is guaranteed to remain—it was designed that way.
For various reasons it was quickly replaced by the CN-7801, but
the CN-7801 and newer chains went back to having
an outer link on one end and an inner link on the other.
With Campagnolo chains,
a cable tie is attached to the fresh outer link at the end, and
it says very clearly: "don't cut from this side."
You can see how seriously they take the fresh outer link.
When I went back to my old workplace the other day, there was
a 6-link piece lying on the floor with the fresh outer link cut off, like in the image above.
Yeah, cutting that side saves you the trouble of using a chain tool!
Next, about link orientation.
If you casually connect the chain, the outer link will end up on either the
「chainring side」or the「rear derailleur side,」
but Shimano recommends the former (the state shown in the diagram above).
This is also a measure to avoid chain breakage as much as possible.
With Campagnolo, they don't state it in text, but
in the manual diagrams, they also show 「outer link on the chainring side,」
so that's what should be done.
With a new chain, this outer link must be a 「fresh outer link.」
These two points are the critical setup considerations for the chain.
So today I shortened the chain by 2 links (= 1 pitch),
and in the image above, the setup is chainring side outer link / rear derailleur side inner link,
with the connect pin joined—this is the correct state.
Before removing the chain pin, I marked
the chainring side with light blue and the rear derailleur side with white.
To remove one pitch, I remove the pins on both sides of the connect pin.
↑This leaves you in this state.
This would be the orientation Shimano doesn't recommend, so
I remove the chain from the bike and flip it front-to-back to reinstall it.
By doing this, the result looks like「one pitch shorter, but still just one connect pin」
In a chain readjustment, you can't connect with a fresh outer link anyway,
but I still think fewer connect pins is better.
This is how I do it when shortening Shimano chains.
The joined part of a chain is normally the part most prone to breaking.
With current Campagnolo 11-speed chain design, I think the joined part is actually strongest,
but in any case, manufacturers are struggling with the fact that narrower chains
have raised the risk of breakage.
If 12-speed or 13-speed components come out in the future,
the chain might be the most difficult component to manufacture.
Going off on a tangent, with 13-speed, an 11-23T would be
11・12・13・14・15・16・17・18・19・20・21・22・23—
with no gaps in tooth count.
If you then made an 11-25T by dropping the 22T and adding a 25T,
I bet pro racers wouldn't complain with just those two options.
Then if you offered 11-28T and 12-28T for amateurs,
they wouldn't have issues either.
13-speed might be the ultimate endpoint.
Though there are issues with rear axle spacing and chainline too.
Campagnolo once had a product called "Permalink"—
a replacement chain part where you'd swap out 7-link sections with fresh outer links on both ends.
By including a connect pin link in the discarded section,
you keep the number of connect pins from increasing unnecessarily, and
any connect pin pressed in is guaranteed to be on a fresh outer link—that was the idea.
You could adjust length by using 5-link or 9-link sections to discard.
This is an example of how much component makers care about chain breakage problems.
If you work on your own bikes, try to be conscious of the 「fresh outer link」
when adjusting your chain.
With a non-fresh outer link, the connect pin tends not to go in straight,
and the crimping can deform the outer link's hole.