The other day I mentioned that of the two wheel pairs I built with Campagnolo Sigma rims,
only the rear wheel with the silver rim had noticeably rough rotation,
and now I'm going to disassemble and clean that hub.
↑The image on the right shows 9 ball bearings from the right side of the hub body,
and the image on the left shows 9 ball bearings from the left side of the hub body,
but only the ball bearings from the left side of the hub body
had scratches and had lost their shine.
↑From a different angle
This is the cone.
There are no signs of pitting damage.
I'm not just showing the same image as before—
I've flipped the cone over.
Even looking at the freehub side of the hub,
there were no obvious pitting marks,
so it looks like the hub can be extended with just a ball bearing replacement.
There's an engraving on the cone—
at the top it says "CAMP" (which stands for Campagnolo)
and at the bottom it says "10×26,"
which indicates the thread pitch in TPI (threads per inch).
Since 25.4÷26=0.97692...,
the other day when I mentioned that a typical rear hub axle has
10×1.0 (1.0mm pitch),
whereas Campagnolo uses 10×0.977—
that's what I was referring to.
TPI stands for "threads per inch"
and the term is also used to describe the fineness of tire casing,
but the word "thread" has both the meaning of yarn and the meaning of thread pitch,
and in bicycles, it just so happens that both of these meanings of "thread"
apply to different components that exist on a bike.
I'm going to reuse the ball bearings from the right side of the hub body (shown on the right of the image),
and I've cleaned and sorted them.
They do appear to be different sizes on left and right—
and that's not just my imagination.
The left side uses 1/4-inch balls, but the right uses 7/32-inch balls,
so the right side of the hub body has a smaller diameter raceway.
only the rear wheel with the silver rim had noticeably rough rotation,
and now I'm going to disassemble and clean that hub.
↑The image on the right shows 9 ball bearings from the right side of the hub body,
and the image on the left shows 9 ball bearings from the left side of the hub body,
but only the ball bearings from the left side of the hub body
had scratches and had lost their shine.
↑From a different angle
This is the cone.
There are no signs of pitting damage.
I'm not just showing the same image as before—
I've flipped the cone over.
Even looking at the freehub side of the hub,
there were no obvious pitting marks,
so it looks like the hub can be extended with just a ball bearing replacement.
There's an engraving on the cone—
at the top it says "CAMP" (which stands for Campagnolo)
and at the bottom it says "10×26,"
which indicates the thread pitch in TPI (threads per inch).
Since 25.4÷26=0.97692...,
the other day when I mentioned that a typical rear hub axle has
10×1.0 (1.0mm pitch),
whereas Campagnolo uses 10×0.977—
that's what I was referring to.
TPI stands for "threads per inch"
and the term is also used to describe the fineness of tire casing,
but the word "thread" has both the meaning of yarn and the meaning of thread pitch,
and in bicycles, it just so happens that both of these meanings of "thread"
apply to different components that exist on a bike.
I'm going to reuse the ball bearings from the right side of the hub body (shown on the right of the image),
and I've cleaned and sorted them.
They do appear to be different sizes on left and right—
and that's not just my imagination.
The left side uses 1/4-inch balls, but the right uses 7/32-inch balls,
so the right side of the hub body has a smaller diameter raceway.