A customer brought in a ZIPP disc wheel for service.
They wanted me to modify the valve hole so they could use
a Hirame (Japanese floor pump) side-cam pump head.
What's taped on there is a balance weight.
It's pure aluminum, exactly 1 gram per piece,
and they're widely distributed throughout Japan
partly as a metal stockpile measure.
Apparently the current ZIPP disc wheels
have a larger valve hole that can accommodate the Hirame side-cam,
but this one doesn't.
The pump head alone fits, but with the valve installed,
it won't go in and you can't pump air.
I expanded it.
About the urethane around the valve hole—
in this wheel's case, it's not completely filled throughout,
rather there's a hollow section toward the inner diameter.
↑Here's a diagram of what it looks like.
So I determined before machining that
sizing it just barely tight enough for the Hirame would leave
a thin layer of urethane remaining.
In the post-machining photo from earlier, there is urethane remaining
on the inner face of the hole, but just a thin film.
Since the current disc wheels apparently have the same dimensions to the hollow section,
I don't think there are any strength concerns.
The customer's desired tire (brought in by the customer)
is a Grapadori 4000S II tubular in 22C,
and I happen to have the same tire for another job, with both being glued on with rim cement.
Interestingly, both turned out to be extremely small-diameter specimens.
They could probably even fit loosely on a 650C rim.
While most people struggle to fit
Competition 22s on the rim, I'm usually able to fit them smoothly,
but this time with the Grapadori 22, I couldn't even
temporarily mount it on the bare rim before applying rim cement.
So I put it on a tire stretcher Y and stretched it.
I thought I might need to leave it overnight,
but it stretched quite a bit in two hours, so I was able to install it.
I've confirmed that the Hirame side-cam fits.
Of course, the customer understands this is contingent on
Brands like TUFO have longer valve stems, so they probably won't work.
For those cases, use an adapter designed specifically for disc wheels.
Also, as an aside about the Hirame (→see here).
They wanted me to modify the valve hole so they could use
a Hirame (Japanese floor pump) side-cam pump head.
What's taped on there is a balance weight.
It's pure aluminum, exactly 1 gram per piece,
and they're widely distributed throughout Japan
partly as a metal stockpile measure.
Apparently the current ZIPP disc wheels
have a larger valve hole that can accommodate the Hirame side-cam,
but this one doesn't.
The pump head alone fits, but with the valve installed,
it won't go in and you can't pump air.
I expanded it.
About the urethane around the valve hole—
in this wheel's case, it's not completely filled throughout,
rather there's a hollow section toward the inner diameter.
↑Here's a diagram of what it looks like.
So I determined before machining that
sizing it just barely tight enough for the Hirame would leave
a thin layer of urethane remaining.
In the post-machining photo from earlier, there is urethane remaining
on the inner face of the hole, but just a thin film.
Since the current disc wheels apparently have the same dimensions to the hollow section,
I don't think there are any strength concerns.
The customer's desired tire (brought in by the customer)
is a Grapadori 4000S II tubular in 22C,
and I happen to have the same tire for another job, with both being glued on with rim cement.
Interestingly, both turned out to be extremely small-diameter specimens.
They could probably even fit loosely on a 650C rim.
While most people struggle to fit
Competition 22s on the rim, I'm usually able to fit them smoothly,
but this time with the Grapadori 22, I couldn't even
temporarily mount it on the bare rim before applying rim cement.
So I put it on a tire stretcher Y and stretched it.
I thought I might need to leave it overnight,
but it stretched quite a bit in two hours, so I was able to install it.
I've confirmed that the Hirame side-cam fits.
Of course, the customer understands this is contingent on
Brands like TUFO have longer valve stems, so they probably won't work.
For those cases, use an adapter designed specifically for disc wheels.
Also, as an aside about the Hirame (→see here).