Another wheel build today (and so on).
The earlier post about building a 24H rim with a 32H hub was written for this wheel project.
It was a real struggle after a long time.
The hub is a Shimano Alfine internal gear hub, but
it has a sprocket on the right side,
and a disc rotor on the left side.
So I can't build it with a 2:1 pattern where one side would be radial laced.
I did consider it though—basically, if you compare the braking time from 40 km/h to a full stop with the acceleration time from zero to 40 km/h,
braking is clearly much faster.
The force from pedaling that pulls the chain and spins the sprocket forward is weaker than
the stopping force applied to the disc rotor (like a two-finger suction grip, or reverse-grip white feather catch if you will).
By that logic, I could solve it negatively by radial-lacing the sprocket side,
but with a 2:1 pattern that would probably reverse the left-right spoke tension difference.
This hub doesn't appear to have offset, but it actually does have some,
just not dimensions that would tolerate a freewheel-side radial 2:1 build.
I... was stuck.
But the customer said "I won't be using the disc brake,"
so I ended up doing an outpoke-side radial 2:1 build.
The rim is an Araya SP-30, but
it's a special size for Bridgestone Moulton—a 17-inch.
I looked into it a bit, and this rim apparently only comes in 24H.
So there was no choice but to do a mismatched hub-and-rim build with the Alfine hub.
If the hub were 36H, the answer would be different, but that's how it goes.
As you can see (though it's cut off), the hole offset is pretty tight.
I'm building it as "right-left-right × 8" instead of "right-left × 12,"
so there are places where the rim holes end up reverse-offset.
For a small-diameter wheel, the angles are tight, but
the "equal-number-spoke-both-sides, spoke length GFEEEFG repeated twice" solution would solve this
but has even bigger problems, so that's out.
Got it built.
Built like this,
and the outpoke side looks like this.
High-end small-diameter wheels often use fewer spokes anyway,
so I'm not worried about the spoke count.
With a super-large-flange hub on a 17-inch rim,
the spokes become even shorter, like those on a truly tiny wheel.
Sometimes you don't interlace the crossings in cases like this,
but this time I did.
I oriented the hub phase visible through the rim's valve hole toward the oil port.
I've set the spoke length to roughly flush with the nipple slot.
That's shorter than what I usually build,
but this rim is single-wall,
so the rim tape goes over the nipples.
If spokes stick out past the nipple, there's a risk of puncturing the tube,
so I kept it conservative.
↑Off topic, but this is my 700C wheel.
When you do twisted lacing, the final crossing ends up quite close to the rim,
so the crossing angle becomes quite obtuse.
When that happens, the spoke's fore-aft angle becomes steeper,
and the nipple rubs and grinds against the front or back of the rim hole.
Aluminum nipples are really weak to this kind of wear, so
I use brass nipples on this wheel.
This wheel had even steeper angles,
so I went with brass nipples here too.
The earlier post about building a 24H rim with a 32H hub was written for this wheel project.
It was a real struggle after a long time.
The hub is a Shimano Alfine internal gear hub, but
it has a sprocket on the right side,
and a disc rotor on the left side.
So I can't build it with a 2:1 pattern where one side would be radial laced.
I did consider it though—basically, if you compare the braking time from 40 km/h to a full stop with the acceleration time from zero to 40 km/h,
braking is clearly much faster.
The force from pedaling that pulls the chain and spins the sprocket forward is weaker than
the stopping force applied to the disc rotor (like a two-finger suction grip, or reverse-grip white feather catch if you will).
By that logic, I could solve it negatively by radial-lacing the sprocket side,
but with a 2:1 pattern that would probably reverse the left-right spoke tension difference.
This hub doesn't appear to have offset, but it actually does have some,
just not dimensions that would tolerate a freewheel-side radial 2:1 build.
I... was stuck.
But the customer said "I won't be using the disc brake,"
so I ended up doing an outpoke-side radial 2:1 build.
The rim is an Araya SP-30, but
it's a special size for Bridgestone Moulton—a 17-inch.
I looked into it a bit, and this rim apparently only comes in 24H.
So there was no choice but to do a mismatched hub-and-rim build with the Alfine hub.
If the hub were 36H, the answer would be different, but that's how it goes.
As you can see (though it's cut off), the hole offset is pretty tight.
I'm building it as "right-left-right × 8" instead of "right-left × 12,"
so there are places where the rim holes end up reverse-offset.
For a small-diameter wheel, the angles are tight, but
the "equal-number-spoke-both-sides, spoke length GFEEEFG repeated twice" solution would solve this
but has even bigger problems, so that's out.
Got it built.
Built like this,
and the outpoke side looks like this.
High-end small-diameter wheels often use fewer spokes anyway,
so I'm not worried about the spoke count.
With a super-large-flange hub on a 17-inch rim,
the spokes become even shorter, like those on a truly tiny wheel.
Sometimes you don't interlace the crossings in cases like this,
but this time I did.
I oriented the hub phase visible through the rim's valve hole toward the oil port.
I've set the spoke length to roughly flush with the nipple slot.
That's shorter than what I usually build,
but this rim is single-wall,
so the rim tape goes over the nipples.
If spokes stick out past the nipple, there's a risk of puncturing the tube,
so I kept it conservative.
↑Off topic, but this is my 700C wheel.
When you do twisted lacing, the final crossing ends up quite close to the rim,
so the crossing angle becomes quite obtuse.
When that happens, the spoke's fore-aft angle becomes steeper,
and the nipple rubs and grinds against the front or back of the rim hole.
Aluminum nipples are really weak to this kind of wear, so
I use brass nipples on this wheel.
This wheel had even steeper angles,
so I went with brass nipples here too.