Another wheel day (details omitted).
A customer left me an ETRTO 451mm rim.
It's a 20-inch WO rim.
(The 20-inch HE is ETRTO 406mm)
The R390 has a single eyeleted rim with no brake zone indicator,
while the DA22 has no eyelets but has indicator grooves running all the way around the brake zone.
In a case like this I'd prefer R390 as the front wheel, but
with front 24H and rear 28H, R390 happens to be 24H anyway,
so there's really no choice—just happens to work out my way.
The hub is American Classic, which the customer left with me.
I always say the rear hub's narrow flanges can't produce lateral stiffness no matter what,
and that's just a fact, so there's nothing to be done about it.
However, when building small-diameter rims, wide flanges make the spoke entry angle too steep,
so narrow flanges are often actually better in these cases.
If I imagine a 700C rim with the same inner diameter as the rim mentioned earlier,
it would be about 105mm in rim height, and
at that dimension, the rim's resistance to deformation combined with
short spokes' resistance to deformation
means the narrow flange rear hub's downsides rarely show themselves.
As for this rear hub, like the Tonka hub I dealt with before,
it's a "problem child for topological reasons."
There are aero slots in the hub flange spoke holes, but
for some reason they're oriented in the direction that spokes might pull.
Seriously, stop doing this.
↑Pulling spokes toward the slot is
clearly not good under any circumstances.
Since the slot directions are staggered,
if you're just doing tangential lacing on one flange,
it's easy to thread spokes in the OK direction shown above.
But if you're also doing tangential lacing on the opposite flange,
depending on phase, you can end up being forced to thread spokes in the slot direction.
If you research it, you'll find that
"when building a rim with spoke hole positions that match most rims in the world
(what this blog calls a 'normal rim'), using same-side lacing with the valve hole positioned between
a 4-spoke set (the final two crossing tangent spokes on one side plus the corresponding two spokes
on the opposite flange)" (basically normal assembly),
and if neither flange's spokes can tension toward the slot direction,
this hub can't be built in either Italian or JIS lacing pattern.
↑This is how you thread the non-freewheel side spokes for Italian lacing.
I threaded them in a phase that avoids tensioning toward the slot direction.
Now for the left drop from here.
Since this is inpoke, whether it's Italian or JIS lacing,
the spokes go toward the porcupine direction, but
↑it ended up biting into the slot direction.
In other words, building this hub normally with same-side lacing in Italian pattern
will inevitably result in one flange's spokes biting into the slot.
For normal building, this hub is JIS-lacing only.
I don't know if other hubs of this same model have the same issue.
In mixed-side lacing with X spokes freewheel-side and Y spokes non-freewheel-side,
if X/2 and Y/2 are both even or both odd,
the right-drop and left-drop relationship doesn't change, but
if they split between even and odd, the phase shifts and
the right-drop and left-drop relationship reverses.
I decided to build it with right-drop 4-6 lacing.
Incidentally, I have another American Classic hub wheel rebuild job pending,
but this one doesn't have slotted flanges, so no problem there.
Besides, I'm not rebuilding it with this hub anyway.
Since the phase selection has half the degrees of freedom, I'm not sure if I can match it,
but I want to position this part of the hub logo
in a spot visible from the valve hole.
Mock-built it. Got a screwdriver in the valve hole.
The valve hole is positioned between a 4-spoke set,
and in that state:
Freewheel-side 4-spoke lacing, with spokes tensioning opposite the slot direction,
Non-freewheel-side 6-spoke lacing, with spokes tensioning opposite the slot direction,
I was able to achieve Italian lacing.
Especially with the 6-spoke side—if you tensioned them the other way, the slot bite would be inevitable,
so anyone tangential lacing this hub should watch carefully and build accordingly.
Even if doing radial lacing on the non-freewheel side, the freewheel side needs the same caution.
That was a long talk, but the wheel is built.
↑For reference, in finished state.
Reverse-tensioned to the slot direction, Italian laced.
Compared to the philosophy of which is better between Italian and JIS lacing,
not tensioning toward the slot is far more critical in this case.
Had I been forced to JIS-lace this time, I would have.
If the slot phase were reversed, even left-drop 4-8 Italian lacing would work,
but since this is a small-diameter rim, true tangential lacing with its steep spoke entry angle
is something I want to avoid.
Lucky—hub phase is perfect.
Not doing cross-lacing.
Narrow flanges mean non-freewheel-side spoke tension is close to freewheel-side,
and short spokes mean deformation is minimal.
I've woven the spoke crossings, but at smaller diameters than this,
either you shouldn't weave or you simply can't.
Spokes are 1.8mm plain DT Champion.
With double-butted spokes, even with spoke cutter processing I couldn't get the required length.
Front wheel built too.
Spokes are also 1.8mm Champion.
This slot is positioned toward the inner diameter, so
no issues whatsoever.
I chose outpoke lacing because it's a small-diameter rim.
I arbitrarily think "inpoke radial lacing becomes undesirable"
for 700C rims around 50mm rim height, but
this one at 105mm equivalent makes outpoke the only choice.
↑Phase is perfect (this one's easy).
A customer left me an ETRTO 451mm rim.
It's a 20-inch WO rim.
(The 20-inch HE is ETRTO 406mm)
The R390 has a single eyeleted rim with no brake zone indicator,
while the DA22 has no eyelets but has indicator grooves running all the way around the brake zone.
In a case like this I'd prefer R390 as the front wheel, but
with front 24H and rear 28H, R390 happens to be 24H anyway,
so there's really no choice—just happens to work out my way.
The hub is American Classic, which the customer left with me.
I always say the rear hub's narrow flanges can't produce lateral stiffness no matter what,
and that's just a fact, so there's nothing to be done about it.
However, when building small-diameter rims, wide flanges make the spoke entry angle too steep,
so narrow flanges are often actually better in these cases.
If I imagine a 700C rim with the same inner diameter as the rim mentioned earlier,
it would be about 105mm in rim height, and
at that dimension, the rim's resistance to deformation combined with
short spokes' resistance to deformation
means the narrow flange rear hub's downsides rarely show themselves.
As for this rear hub, like the Tonka hub I dealt with before,
it's a "problem child for topological reasons."
There are aero slots in the hub flange spoke holes, but
for some reason they're oriented in the direction that spokes might pull.
Seriously, stop doing this.
↑Pulling spokes toward the slot is
clearly not good under any circumstances.
Since the slot directions are staggered,
if you're just doing tangential lacing on one flange,
it's easy to thread spokes in the OK direction shown above.
But if you're also doing tangential lacing on the opposite flange,
depending on phase, you can end up being forced to thread spokes in the slot direction.
If you research it, you'll find that
"when building a rim with spoke hole positions that match most rims in the world
(what this blog calls a 'normal rim'), using same-side lacing with the valve hole positioned between
a 4-spoke set (the final two crossing tangent spokes on one side plus the corresponding two spokes
on the opposite flange)" (basically normal assembly),
and if neither flange's spokes can tension toward the slot direction,
this hub can't be built in either Italian or JIS lacing pattern.
↑This is how you thread the non-freewheel side spokes for Italian lacing.
I threaded them in a phase that avoids tensioning toward the slot direction.
Now for the left drop from here.
Since this is inpoke, whether it's Italian or JIS lacing,
the spokes go toward the porcupine direction, but
↑it ended up biting into the slot direction.
In other words, building this hub normally with same-side lacing in Italian pattern
will inevitably result in one flange's spokes biting into the slot.
For normal building, this hub is JIS-lacing only.
I don't know if other hubs of this same model have the same issue.
In mixed-side lacing with X spokes freewheel-side and Y spokes non-freewheel-side,
if X/2 and Y/2 are both even or both odd,
the right-drop and left-drop relationship doesn't change, but
if they split between even and odd, the phase shifts and
the right-drop and left-drop relationship reverses.
I decided to build it with right-drop 4-6 lacing.
Incidentally, I have another American Classic hub wheel rebuild job pending,
but this one doesn't have slotted flanges, so no problem there.
Besides, I'm not rebuilding it with this hub anyway.
Since the phase selection has half the degrees of freedom, I'm not sure if I can match it,
but I want to position this part of the hub logo
in a spot visible from the valve hole.
Mock-built it. Got a screwdriver in the valve hole.
The valve hole is positioned between a 4-spoke set,
and in that state:
Freewheel-side 4-spoke lacing, with spokes tensioning opposite the slot direction,
Non-freewheel-side 6-spoke lacing, with spokes tensioning opposite the slot direction,
I was able to achieve Italian lacing.
Especially with the 6-spoke side—if you tensioned them the other way, the slot bite would be inevitable,
so anyone tangential lacing this hub should watch carefully and build accordingly.
Even if doing radial lacing on the non-freewheel side, the freewheel side needs the same caution.
That was a long talk, but the wheel is built.
↑For reference, in finished state.
Reverse-tensioned to the slot direction, Italian laced.
Compared to the philosophy of which is better between Italian and JIS lacing,
not tensioning toward the slot is far more critical in this case.
Had I been forced to JIS-lace this time, I would have.
If the slot phase were reversed, even left-drop 4-8 Italian lacing would work,
but since this is a small-diameter rim, true tangential lacing with its steep spoke entry angle
is something I want to avoid.
Lucky—hub phase is perfect.
Not doing cross-lacing.
Narrow flanges mean non-freewheel-side spoke tension is close to freewheel-side,
and short spokes mean deformation is minimal.
I've woven the spoke crossings, but at smaller diameters than this,
either you shouldn't weave or you simply can't.
Spokes are 1.8mm plain DT Champion.
With double-butted spokes, even with spoke cutter processing I couldn't get the required length.
Front wheel built too.
Spokes are also 1.8mm Champion.
This slot is positioned toward the inner diameter, so
no issues whatsoever.
I chose outpoke lacing because it's a small-diameter rim.
I arbitrarily think "inpoke radial lacing becomes undesirable"
for 700C rims around 50mm rim height, but
this one at 105mm equivalent makes outpoke the only choice.
↑Phase is perfect (this one's easy).