Nomu Lab Diary

Rebuilt a Sigma Rim Wheel (Rear Wheel, Part 1)

Another wheel day (and so on...).
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A customer brought in a rear wheel
that we'd built here some time ago.

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The hub is a G2-series hub body
like PowerTap SL+ or Elite+,

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with an embedded G3-series unit,
32H, semi-competition, four-cross lacing with spoke tie-ins.

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The rim is a Campagnolo Sigma tubular,
with nipples that are basically silver,

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except at the valve hole position opposite,
where we've used nipples in a color meant to evoke
Arc-en-ciel.
We'll keep it the same way after the rebuild.

The hub has failed,
so the customer wants it rebuilt
without the power meter function.
For a 32H hub that can be set up with an XDR freebody,
options like Novatec and DT come to mind, but

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we're going with a vintage Record hub
silver hub shell with grease ports from that era—
set up with an XDR freebody.

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↑This is the non-drive-side hub flange viewed from the outside,
and it has spoke lacing history of at least two builds
(probably just two, actually)—
there are holes, spaced every other position,
that show both inpoke marks
and outpoke marks.
So I thought the history might be Italian lacing and JIS lacing, but

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when I looked at the outside of the drive-side flange,
all holes showed outpoke marks,
so the history is actually reverse-Italian lacing and reverse-JIS lacing.

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To swap in the XDR freebody,
the hub axle needs to be changed to the later type
with center dishing and three-way notches, but

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that later-model rear hub axle comes in two versions:
FH-BO 001 and 101.
As it happens, the image above shows the older 001 model
in a newer-era box due to restocking timing.

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↑The top image is 001, bottom is 101,
and the thread pitch of the
bearing adjustment locknut is different.
The newer 101 model makes
fine adjustment easier
(since both are infinitely adjustable the adjustment itself is the same,
but finer pitch means less lateral movement of the nut
per revolution).

When upgrading the rear wheel of a complete wheel set using 001
to 101, you naturally need to change the
split locknut to a different pitch version as well, but

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this Record hub bearing adjustment locknut
is only available in the 001-compatible version,
so the hub axle needs to be 001.

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Swapping out the hub axle.

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Built the wheel.

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The fact that this hub can be upgraded to a freebody
that didn't even exist when it was released
speaks to Campagnolo's parts design consistency.
We're not doing it this time, but
this hub is also the oldest one that can be
retrofitted with CULT bearings,
which hadn't been invented yet when it came out.

Record hub, 32H, semi-competition,
four-cross Italian lacing.
We'll do the spoke tie-ins later.

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The original Campagnolo freebody,
but its three pawls weren't engaging properly, so
I took out the springs and found one was deformed.

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