Today it's wheels again (and so on)... but first.
These are actual bike photos from my mentor,
taken a while back when I wanted some close-up shots
of an American Classic CR350 rim.
But it turned out the rim wasn't a CR350—it was a Sprint 350 instead.
Back in the day, American Classic made
the CR350 and CR420 rims, which are clincher rims
with nominal weights of 350g and 420g respectively,
and the actual measured weights pretty much matched the name.
These were ultra-light aluminum rims for their time.
The Sprint 350 is the successor to the CR350,
but both the CR350 and CR420 have brake zones with heights
similar to Shimano cartridge brake shoes,
so as the shoes wear from their initial position,
they'll eventually protrude beyond the brake zone.
Also, the CR350 isn't really a rim you can tension up very tightly.
If you try to pull the spokes hard,
the rim will snake side-to-side under spoke tension.
The CR420 is slightly better, but shows the same tendency,
so the aluminum material seems quite soft.
Among other lightweight aluminum rims around 360g,
the ALEXRIMS Crostini R3.1 is also a soft rim,
and the early Stans ZTR Alpha 340 feels stiff when tensioned
but is so hard it actually develops cracks in the rim holes.
I've written before about how the Nomu Lab Wheel No. 5 rim
is abnormal in a good way, all things considered (→here).
This Sprint 350 rim in the opening photos is better than the CR350
but still can't be tensioned that high.
The whole story of how my mentor ended up with this wheelset is that
a teammate with an Akamatu frame said
"It's too mushy, I don't want it" and left it with him.
My mentor says "The rim is light and the ride feel is just right,"
so he's happy with it.
Anyway, wheels again (and so on).
A customer brought me an American Classic
Sprint 350 tubeless rim pre-built wheelset.
The rim is labeled Sprint 350 Tubeless,
much narrower than today's wide rims
but wider than the regular Sprint 350.
The hub is also American Classic,
24 holes, 4-cross Italian lacing.
Someone might say that just because a wheel has
American Classic rims and hubs doesn't mean it's a factory build,
but get this—
The black butted spokes have "AC" stamped on them,
and unless the Japan Public Advertising Organization is involved,
that means American Classic branded spokes.
Based on magnetic magnetic properties as a judge of tensile strength,
they're nearly non-magnetic stainless steel,
so they're pretty weak spokes.
↑Only these two spokes use white spokes,
but the paint adhesion was weak and peeling off like eggshell.
A spoke has come loose from the rim.
Rather than just patching this section,
the customer wants a complete spoke replacement, meaning a full wheel rebuild.
The spoke is bent, but that's not because it broke—
it's because the nipple corroded and broke.
There are other areas where corrosion is progressing.
These spokes are definitely not OEM Sapim,
but the nipples, which can be turned with a 3.2mm hex key from the outside,
might be Sapim brand.
The 14mm silver aluminum nipples that come with
Sapim Silver CX-RAY show this same kind of corrosion,
which is why I don't use Sapim nipples (especially silver ones).
The rim turned out lighter than expected.
This narrower, non-tubeless variant
weighs about 360g despite the "350" name,
so the weight increase from different specs
is almost negligible.
The original butted spokes are, by gauge,
the same as DT Competition 14-base.
The customer wants a complete rebuild with silver spokes
and spoke-tied lacing,
but this rim, unlike typical American Classic rims I know,
has surprising stiffness—
not the good kind where you can tension it hard,
but a dangerous fragility like Stans rims that might crack under tension,
so I'm keeping the freewheel side tension exactly as original
(with one spoke missing on the non-freewheel side, though that doesn't affect the judgment)
and since we're using all-competition spokes with no asymmetric lacing to rely on,
I'm going with 4-cross Italian lacing with spoke-tied lacing
to minimize deformation on the non-freewheel side spokes as much as possible.
It's built.
32 holes, all-competition spokes, 4-cross Italian lacing with spoke-tied lacing.
Despite having relatively narrow flanges,
this hub shows large differences in left/right spoke tension.
That's because the freewheel side flange is narrow
and the ochoco is tight.
For example, even if both have 51mm total flange width,
the difference between 34mm left/17mm right and 32mm left/19mm right is huge
in how the wheel feels when building and the final result.
This hub is roughly the former dimension,
and the 2mm difference on the non-freewheel side isn't a big deal,
but the 1-2mm on the freewheel side is enormous.
If this wheel had no spoke-tied lacing,
it would be "tensioned only as much as the correction
for any hop or centering error that might have existed in the original wheel,
with tension gain only from the 4-cross difference if the original wheel was built to high precision".
Going back chronologically,
the clear yellow tubeless tape
that was originally applied—
the top layer (left in the image above) peels off easily,
leaving another layer of transparent adhesive tape (right in the image above)
on the rim—
completely removing that adhesive tape was a hassle.
After building the wheel, I applied Stans tape.
The image above shows a temporary tire and tube mounted
and pressurized to 7 psi to seat the tape on the rim.
These are actual bike photos from my mentor,
taken a while back when I wanted some close-up shots
of an American Classic CR350 rim.
But it turned out the rim wasn't a CR350—it was a Sprint 350 instead.
Back in the day, American Classic made
the CR350 and CR420 rims, which are clincher rims
with nominal weights of 350g and 420g respectively,
and the actual measured weights pretty much matched the name.
These were ultra-light aluminum rims for their time.
The Sprint 350 is the successor to the CR350,
but both the CR350 and CR420 have brake zones with heights
similar to Shimano cartridge brake shoes,
so as the shoes wear from their initial position,
they'll eventually protrude beyond the brake zone.
Also, the CR350 isn't really a rim you can tension up very tightly.
If you try to pull the spokes hard,
the rim will snake side-to-side under spoke tension.
The CR420 is slightly better, but shows the same tendency,
so the aluminum material seems quite soft.
Among other lightweight aluminum rims around 360g,
the ALEXRIMS Crostini R3.1 is also a soft rim,
and the early Stans ZTR Alpha 340 feels stiff when tensioned
but is so hard it actually develops cracks in the rim holes.
I've written before about how the Nomu Lab Wheel No. 5 rim
is abnormal in a good way, all things considered (→here).
This Sprint 350 rim in the opening photos is better than the CR350
but still can't be tensioned that high.
The whole story of how my mentor ended up with this wheelset is that
a teammate with an Akamatu frame said
"It's too mushy, I don't want it" and left it with him.
My mentor says "The rim is light and the ride feel is just right,"
so he's happy with it.
Anyway, wheels again (and so on).
A customer brought me an American Classic
Sprint 350 tubeless rim pre-built wheelset.
The rim is labeled Sprint 350 Tubeless,
much narrower than today's wide rims
but wider than the regular Sprint 350.
The hub is also American Classic,
24 holes, 4-cross Italian lacing.
Someone might say that just because a wheel has
American Classic rims and hubs doesn't mean it's a factory build,
but get this—
The black butted spokes have "AC" stamped on them,
and unless the Japan Public Advertising Organization is involved,
that means American Classic branded spokes.
they're nearly non-magnetic stainless steel,
so they're pretty weak spokes.
↑Only these two spokes use white spokes,
but the paint adhesion was weak and peeling off like eggshell.
A spoke has come loose from the rim.
Rather than just patching this section,
the customer wants a complete spoke replacement, meaning a full wheel rebuild.
The spoke is bent, but that's not because it broke—
it's because the nipple corroded and broke.
There are other areas where corrosion is progressing.
These spokes are definitely not OEM Sapim,
but the nipples, which can be turned with a 3.2mm hex key from the outside,
might be Sapim brand.
The 14mm silver aluminum nipples that come with
Sapim Silver CX-RAY show this same kind of corrosion,
which is why I don't use Sapim nipples (especially silver ones).
The rim turned out lighter than expected.
This narrower, non-tubeless variant
weighs about 360g despite the "350" name,
so the weight increase from different specs
is almost negligible.
The original butted spokes are, by gauge,
the same as DT Competition 14-base.
The customer wants a complete rebuild with silver spokes
and spoke-tied lacing,
but this rim, unlike typical American Classic rims I know,
has surprising stiffness—
not the good kind where you can tension it hard,
but a dangerous fragility like Stans rims that might crack under tension,
so I'm keeping the freewheel side tension exactly as original
(with one spoke missing on the non-freewheel side, though that doesn't affect the judgment)
and since we're using all-competition spokes with no asymmetric lacing to rely on,
I'm going with 4-cross Italian lacing with spoke-tied lacing
to minimize deformation on the non-freewheel side spokes as much as possible.
It's built.
32 holes, all-competition spokes, 4-cross Italian lacing with spoke-tied lacing.
Despite having relatively narrow flanges,
this hub shows large differences in left/right spoke tension.
That's because the freewheel side flange is narrow
and the ochoco is tight.
For example, even if both have 51mm total flange width,
the difference between 34mm left/17mm right and 32mm left/19mm right is huge
in how the wheel feels when building and the final result.
This hub is roughly the former dimension,
and the 2mm difference on the non-freewheel side isn't a big deal,
but the 1-2mm on the freewheel side is enormous.
If this wheel had no spoke-tied lacing,
it would be "tensioned only as much as the correction
for any hop or centering error that might have existed in the original wheel,
with tension gain only from the 4-cross difference if the original wheel was built to high precision".
Going back chronologically,
the clear yellow tubeless tape
that was originally applied—
the top layer (left in the image above) peels off easily,
leaving another layer of transparent adhesive tape (right in the image above)
on the rim—
completely removing that adhesive tape was a hassle.
After building the wheel, I applied Stans tape.
The image above shows a temporary tire and tube mounted
and pressurized to 7 psi to seat the tape on the rim.