Another wheel day (and so on).
I built a rear wheel using an Open Pro Carbon 25 UST rim.
The bag the rim came in said
Open Pro Carbon UST,
but the rim itself is labeled
Open Pro Carbon 25 UST, including the rim height information.
The actual rim height measured 25.4mm.
It probably wasn't intentional with an inch dimension in mind.
As a side note, regarding carbon rim heights,
while 50mm is a nice round number,
38mm appears quite frequently, which is likely
a holdover from when Americans
made rims at 2 inches (50.8mm) and
1.5 inches (38.1mm).
At first glance, you might think this rim name is
derived from Open Pro,
but based on the naming convention of the
CXP Pro Carbon 40 UST rim I built recently,
it breaks down as
CXP + Pro Carbon grade + rim height + UST standard,
so the base rim model name should be
"Open" rather than "Open Pro".
Mavic once had a model called Cosmic Carbon,
and later released Cosmic Pro Carbon,
but this isn't "Pro" inserted between Cosmic Carbon—
rather it can be interpreted as
the model name Cosmic + the Pro Carbon grade.
Shimano WH-RS80 hub, 20H,
Campagnolo/CX Sprint forced left-right 2-cross lacing.
With the WH-RS80, the final crossing isn't woven on either side,
but with this rear wheel, the final crossing is woven on both sides
and the anti-freewheel side is then laced.
Naturally, weaving the final crossing is a requirement for lacing.
This hub supports up to 10-speed,
but not 11-speed (or 12-speed),
though apparently that's not an issue.
The hub I received was so seized up
that the hub axle couldn't be turned by hand.
After applying strong force once and hearing a click,
it now rotates normally with a grinding sensation.
This was a case where bearing components
had become lightly bonded by rust,
which I released.
The image above shows the hub after disassembly
with parts cleaner sprayed on it.
The damage was merely surface corrosion on the ball bearings,
and the ball races and cone showed
no signs of pitting, so
I replaced only the Shibuichi bearing balls.
Shibuichi (quarter-inch) is
the colloquial term for 1/4-inch diameter balls.
Shimano has traditionally
used stainless steel balls only in
Dura-Ace hubs sold individually or
in complete wheelsets.
At least in the pre-cartridge bearing era, that was the case.
The RS80 is outside-grade RS (Road Series),
which is Altegra-level, and
according to the spare parts catalog,
steel balls are specified.
I've long wondered whether stainless steel balls are necessary
if the hub is adequately filled with grease,
but in situations like when this hub was received,
where you wouldn't notice and kept using it,
the difference might show up.
That said, "back then" Dura-Ace hubs
had exceptionally robust labyrinth seals
and water barely entered even from rain unless hit with a pressure washer,
and when amateur riders attempted overhauls,
the hub internals were more often damaged than otherwise.
With C24 rims, rim lifespan is
significantly shorter than hub lifespan, so
effectively maintenance-free
(the rim dies before the hub needs service,
plus by then the spokes are completely rusted)
—so having stainless steel balls is somewhat pointless.
I wrote "back then" because
current R9270 wheel hubs
have noticeably worse water resistance
compared to traditional Dura-Ace hubs.
Even riders who don't actively ride in rain
and have almost never been caught in unexpected showers
are experiencing instances of cartridge bearing areas rusting
within a year or so.
If you approach current hubs with the maintenance schedule of previous Dura-Ace hubs, you'll have problems—which seems to be a trap lurking for experienced riders.
I built a rear wheel using an Open Pro Carbon 25 UST rim.
The bag the rim came in said
Open Pro Carbon UST,
but the rim itself is labeled
Open Pro Carbon 25 UST, including the rim height information.
The actual rim height measured 25.4mm.
It probably wasn't intentional with an inch dimension in mind.
As a side note, regarding carbon rim heights,
while 50mm is a nice round number,
38mm appears quite frequently, which is likely
a holdover from when Americans
made rims at 2 inches (50.8mm) and
1.5 inches (38.1mm).
At first glance, you might think this rim name is
derived from Open Pro,
but based on the naming convention of the
CXP Pro Carbon 40 UST rim I built recently,
it breaks down as
CXP + Pro Carbon grade + rim height + UST standard,
so the base rim model name should be
"Open" rather than "Open Pro".
Mavic once had a model called Cosmic Carbon,
and later released Cosmic Pro Carbon,
but this isn't "Pro" inserted between Cosmic Carbon—
rather it can be interpreted as
the model name Cosmic + the Pro Carbon grade.
Shimano WH-RS80 hub, 20H,
Campagnolo/CX Sprint forced left-right 2-cross lacing.
With the WH-RS80, the final crossing isn't woven on either side,
but with this rear wheel, the final crossing is woven on both sides
and the anti-freewheel side is then laced.
Naturally, weaving the final crossing is a requirement for lacing.
This hub supports up to 10-speed,
but not 11-speed (or 12-speed),
though apparently that's not an issue.
The hub I received was so seized up
that the hub axle couldn't be turned by hand.
After applying strong force once and hearing a click,
it now rotates normally with a grinding sensation.
This was a case where bearing components
had become lightly bonded by rust,
which I released.
The image above shows the hub after disassembly
with parts cleaner sprayed on it.
The damage was merely surface corrosion on the ball bearings,
and the ball races and cone showed
no signs of pitting, so
I replaced only the Shibuichi bearing balls.
Shibuichi (quarter-inch) is
the colloquial term for 1/4-inch diameter balls.
Shimano has traditionally
used stainless steel balls only in
Dura-Ace hubs sold individually or
in complete wheelsets.
At least in the pre-cartridge bearing era, that was the case.
The RS80 is outside-grade RS (Road Series),
which is Altegra-level, and
according to the spare parts catalog,
steel balls are specified.
I've long wondered whether stainless steel balls are necessary
if the hub is adequately filled with grease,
but in situations like when this hub was received,
where you wouldn't notice and kept using it,
the difference might show up.
That said, "back then" Dura-Ace hubs
had exceptionally robust labyrinth seals
and water barely entered even from rain unless hit with a pressure washer,
and when amateur riders attempted overhauls,
the hub internals were more often damaged than otherwise.
With C24 rims, rim lifespan is
significantly shorter than hub lifespan, so
effectively maintenance-free
(the rim dies before the hub needs service,
plus by then the spokes are completely rusted)
—so having stainless steel balls is somewhat pointless.
I wrote "back then" because
current R9270 wheel hubs
have noticeably worse water resistance
compared to traditional Dura-Ace hubs.
Even riders who don't actively ride in rain
and have almost never been caught in unexpected showers
are experiencing instances of cartridge bearing areas rusting
within a year or so.
If you approach current hubs with the maintenance schedule of previous Dura-Ace hubs, you'll have problems—which seems to be a trap lurking for experienced riders.