There were issues like the Hollowtech II crank not passing through smoothly
and the crank spindle protrusion being clearly insufficient,
so I was worried, but it turned out to be no big deal.
It's one of those BB units where "Rotor makes the cup section,
Ceramic Speed makes the bearings, and the BB hardware fits as-is — a real treasure."
The issue was that the dust cap on the left side was sticking out,
but what was actually sticking out wasn't the dust cap itself,
but the bearing underneath it.
The image above shows the left bearing with the dust cap removed.
↑Right side cup with dust cap removed.
A straightedge placed perpendicular to the cup doesn't touch the bearing.
On the left side, the straightedge does touch.
Also, the distance to the straightedge changes slightly depending on the bearing position,
so the bearing's press-fit came out slightly at an angle.
Using a press tool the same diameter as the bearing outer race
when I pressed it in, it went right into place.
I could feel the angled bearing straighten out and seat properly.
↑Left side after press-fitting
In actual use, the dust cap goes on, and
even with the dust cap installed, I confirmed that you can touch the crank spindle end
to the inner race of the left bearing from the inside.
Maybe this bearing was subjected to pushing or hammering while in this state.
↑Right side with dust cap installed
↑Same, left side
I fitted the crank through.
It passes all the way in with just hand pressure.
The crank spindle is slightly thicker only at the section directly below the bearing
(or more precisely, everything else is thinner),
but with some BB units that have slightly tight tolerances,
passing the crank spindle through can be difficult
(like with Wishbone BB units).
In those cases, you'd need to apply oil or
fluorine-based chemical lubricant to the crank spindle and
apply gentle impact force, but
this one went in smoothly.
And it comes out easily too, just using hand pressure.
With some BB units, the installation width is wider than genuine Shimano BB,
so the crank spindle protrusion on the left side is reduced,
but that's not an issue here.
When it's wider, only the spline grooves stick out,
and sometimes you can't insert the left crank retention plate
into the crank spindle hole.
and the crank spindle protrusion being clearly insufficient,
so I was worried, but it turned out to be no big deal.
It's one of those BB units where "Rotor makes the cup section,
Ceramic Speed makes the bearings, and the BB hardware fits as-is — a real treasure."
The issue was that the dust cap on the left side was sticking out,
but what was actually sticking out wasn't the dust cap itself,
but the bearing underneath it.
The image above shows the left bearing with the dust cap removed.
↑Right side cup with dust cap removed.
A straightedge placed perpendicular to the cup doesn't touch the bearing.
On the left side, the straightedge does touch.
Also, the distance to the straightedge changes slightly depending on the bearing position,
so the bearing's press-fit came out slightly at an angle.
Using a press tool the same diameter as the bearing outer race
when I pressed it in, it went right into place.
I could feel the angled bearing straighten out and seat properly.
↑Left side after press-fitting
In actual use, the dust cap goes on, and
even with the dust cap installed, I confirmed that you can touch the crank spindle end
to the inner race of the left bearing from the inside.
Maybe this bearing was subjected to pushing or hammering while in this state.
↑Right side with dust cap installed
↑Same, left side
I fitted the crank through.
It passes all the way in with just hand pressure.
The crank spindle is slightly thicker only at the section directly below the bearing
(or more precisely, everything else is thinner),
but with some BB units that have slightly tight tolerances,
passing the crank spindle through can be difficult
(like with Wishbone BB units).
In those cases, you'd need to apply oil or
fluorine-based chemical lubricant to the crank spindle and
apply gentle impact force, but
this one went in smoothly.
And it comes out easily too, just using hand pressure.
With some BB units, the installation width is wider than genuine Shimano BB,
so the crank spindle protrusion on the left side is reduced,
but that's not an issue here.
When it's wider, only the spline grooves stick out,
and sometimes you can't insert the left crank retention plate
into the crank spindle hole.