I never thought I'd be writing about something like this.
Today I replaced a customer's chain,
and it was installed backwards.
The customer didn't install it themselves.
It was a shop that did this, and while they have multiple staff members,
aside from one person who does reasonably decent work,
they do pretty sloppy maintenance overall,
and I've been dealing with them regularly as a patsy.
(Thanks for everything!)
Poor shifting performance might be because of the rotor chainring as you can see,
or maybe the chain is stretched,
but the fact is it was installed incorrectly right out of the box
means it was never performing at 100%.
So, about how to tell which way is correct:
↑From the right side
↑From the left side
"The side of the outer plate that has some kind of marking should face the right side."
That's the correct answer.
So this state is wrong.
This chain is CN-HG700, but
Dura-Ace was HG900, Ultegra was HG700, 105 was HG600,
and with the current models the model numbers have advanced by one at the end: 901, 701, 601.
By the way, from when the minor change happened,
701 was the first to change.
For this chain replacement, I'm also upgrading from 700 to 701.
The side with marking (right side/outer side)
The side without marking (left side/inner side)
The corner cut of the outer plate on the side without marking is different from the other side.
Regarding the reason for this shape, Shimano touts
"smooth gear shifts under high-load shifting"
and "quiet pedaling,"
but if the side without marking is installed on the inside,
it looks like a cutting that would improve chain disengagement from below the chainring and above the sprocket,
so I think "quiet pedaling" (especially when the chain is angled on the outer×low combination)
is the main reason.
As for chain direction, there's no way to get it wrong—
it's written on the bag with illustrations,
but I guess it didn't catch their eye.
I installed the CN-HG701 in the correct direction.
More time was spent fixing the sloppy outer cable routing (which the customer was concerned about too)
than on the actual chain replacement itself.
If you're using an HG900-series or later 11-speed chain,
I'd recommend double-checking the direction.
That said, when I write things like this,
somewhere out there the chain of events unfolds like:
"I read the Nomu Lab Diary, found out that work I paid a pro to do was wrong,
so I complained to that nearby shop!"
and this happens without my knowledge,
the customer suddenly gainedunnecessary knowledge and the source gets exposed here,
and I end up being resented by some random shop I don't even know—
that sequence definitely exists.
Not that I mind.
Even if it's just among people who read this and their acquaintances,
if it eliminates chain installation direction mistakes, that's fine by me.
Today I replaced a customer's chain,
and it was installed backwards.
The customer didn't install it themselves.
It was a shop that did this, and while they have multiple staff members,
aside from one person who does reasonably decent work,
they do pretty sloppy maintenance overall,
and I've been dealing with them regularly as a patsy.
Poor shifting performance might be because of the rotor chainring as you can see,
or maybe the chain is stretched,
but the fact is it was installed incorrectly right out of the box
means it was never performing at 100%.
So, about how to tell which way is correct:
↑From the right side
↑From the left side
"The side of the outer plate that has some kind of marking should face the right side."
That's the correct answer.
So this state is wrong.
This chain is CN-HG700, but
Dura-Ace was HG900, Ultegra was HG700, 105 was HG600,
and with the current models the model numbers have advanced by one at the end: 901, 701, 601.
By the way, from when the minor change happened,
701 was the first to change.
For this chain replacement, I'm also upgrading from 700 to 701.
The side with marking (right side/outer side)
The side without marking (left side/inner side)
The corner cut of the outer plate on the side without marking is different from the other side.
Regarding the reason for this shape, Shimano touts
"smooth gear shifts under high-load shifting"
and "quiet pedaling,"
but if the side without marking is installed on the inside,
it looks like a cutting that would improve chain disengagement from below the chainring and above the sprocket,
so I think "quiet pedaling" (especially when the chain is angled on the outer×low combination)
is the main reason.
As for chain direction, there's no way to get it wrong—
it's written on the bag with illustrations,
but I guess it didn't catch their eye.
I installed the CN-HG701 in the correct direction.
More time was spent fixing the sloppy outer cable routing (which the customer was concerned about too)
than on the actual chain replacement itself.
If you're using an HG900-series or later 11-speed chain,
I'd recommend double-checking the direction.
That said, when I write things like this,
somewhere out there the chain of events unfolds like:
"I read the Nomu Lab Diary, found out that work I paid a pro to do was wrong,
so I complained to that nearby shop!"
and this happens without my knowledge,
the customer suddenly gained
and I end up being resented by some random shop I don't even know—
that sequence definitely exists.
Not that I mind.
Even if it's just among people who read this and their acquaintances,
if it eliminates chain installation direction mistakes, that's fine by me.