I received a WH-7800 from a customer.
They want me to check runout and centering,
plus do a hub overhaul.
Shimano was the originator of the freehub body design for rear hubs,
so they engineered the freehub to overcome the weak points
of the older boss hub standard.
Shimano freehubs use a cup-and-cone bearing system with
the left bearing at the left end of the hub shell
and the right bearing at the right end of the freehub body—
a format they've stuck with all the way to current models.
Except for this WH-7800 through 7801 hub period.
One of the motivations behind freehub design was to expand
bearing width from boss hubs, so
instead of the four bearings most modern freehubs use—
a pair on the left and right of the hub shell plus a pair on the freehub body—
the design has bearings only at both ends of the rear hub.
So when you remove the freehub body from a Shimano hub,
there's only one bearing on the left side.
But with the 7800 hub, for reasons I can't fathom,
they completely copied Campagnolo's hub structure.
I'll do the hub overhaul first.
The rear wheel had play in the bearing adjustment,
but you can't do precise truing while there's play,
so I'm tackling that first.
It's the kind of obvious thing anyone might think of,
so I won't say it's copying Campagnolo or Fulcrum,
but this end nut has reverse threads.
There's even a directional marking, just to be safe.
I could've gotten away with just a grease touch-up,
but I wanted to check whether the bearing races were damaged
from the play, so I decided to clean it out.
There's that subtle kind of wear where
the shaft feels fine when you spin it by hand,
but when you take it apart you find early-stage spalling.
↑Wow, looking at it this way, it really does look just like Fulcrum.
Sorry, I used the wrong image.
That one really was Fulcrum.
This is the 7800.
The 7800 hub comes in early and late versions, and this is the early type.
The difference is whether the anti-freehub bearing is loose balls or a retainer cage.
Loose balls = early type, retainer = late type.
The spare parts catalog calls them A and B respectively,
but basically, partway through they thought "maybe the retainer is better"
and quietly changed the spec, without changing any part stampings or markings
to "7800-B" or whatever. It just stayed "7800"
and switched over to the B version once A stock sold out.
Back then, if you ordered "a 7800 hub (or wheel)!" from a distributor,
there was a period when you had no idea which one would show up. That was annoying.
The successor WH-7801 hub and wheels
only use retainer-type bearings on the anti-freehub side.
As for whether retainer or loose balls is better—
retainer wins long-term, loose balls short-term.
You should not do the modification where you take the ceramic balls out of
a Campagnolo CULT retainer ring, increase the ball count,
and resettle them as loose balls—the so-called "ball CULT" conversion.
I honestly don't understand why that made-up term even exists. Ugh.
It seems like it was used with play for a while,
but the bearing races weren't damaged at all.
The steel balls (Dura-Ace uses stainless) were in excellent condition too,
so I'll grease them up and reassemble.
That's one of the nice things about Dura-Ace hubs—really high durability.
↑The C-shaped spring on the freehub body pawl
looks just like Novatech, not Campagnolo.
Hub-side nipples feel like overkill from a design perspective,
but the person who gets frustrated dealing with them
is me, not the customer, so if it means a better wheel,
I couldn't care less about that kind of minor inconvenience.
Or so I thought...
The rim was drifting toward the freehub side, so to center it
I had to evenly increase tension on the anti-freehub side nipples.
And I mean really increase it.
Those ten nipples in the photo
each turned about three-quarters of a rotation.
Extremely tedious.
I really don't mind this kind of work,
but team mechanics would hate this. Definitely.
It's easy to say "maintenance hassle doesn't matter if performance is good" when you run a shop.
The rear wheel's bearing was shaken up by the play,
so the grease was pitch black,
but the front wheel had no play and the grease kept its original color,
so I just topped it off without cleaning and regreased it.
The front wheel had almost no centering drift or runout,
so most of today's work time went into the rear wheel.
They want me to check runout and centering,
plus do a hub overhaul.
Shimano was the originator of the freehub body design for rear hubs,
so they engineered the freehub to overcome the weak points
of the older boss hub standard.
Shimano freehubs use a cup-and-cone bearing system with
the left bearing at the left end of the hub shell
and the right bearing at the right end of the freehub body—
a format they've stuck with all the way to current models.
Except for this WH-7800 through 7801 hub period.
One of the motivations behind freehub design was to expand
bearing width from boss hubs, so
instead of the four bearings most modern freehubs use—
a pair on the left and right of the hub shell plus a pair on the freehub body—
the design has bearings only at both ends of the rear hub.
So when you remove the freehub body from a Shimano hub,
there's only one bearing on the left side.
But with the 7800 hub, for reasons I can't fathom,
they completely copied Campagnolo's hub structure.
I'll do the hub overhaul first.
The rear wheel had play in the bearing adjustment,
but you can't do precise truing while there's play,
so I'm tackling that first.
It's the kind of obvious thing anyone might think of,
so I won't say it's copying Campagnolo or Fulcrum,
but this end nut has reverse threads.
There's even a directional marking, just to be safe.
I could've gotten away with just a grease touch-up,
but I wanted to check whether the bearing races were damaged
from the play, so I decided to clean it out.
There's that subtle kind of wear where
the shaft feels fine when you spin it by hand,
but when you take it apart you find early-stage spalling.
↑Wow, looking at it this way, it really does look just like Fulcrum.
Sorry, I used the wrong image.
That one really was Fulcrum.
This is the 7800.
The 7800 hub comes in early and late versions, and this is the early type.
The difference is whether the anti-freehub bearing is loose balls or a retainer cage.
Loose balls = early type, retainer = late type.
The spare parts catalog calls them A and B respectively,
but basically, partway through they thought "maybe the retainer is better"
and quietly changed the spec, without changing any part stampings or markings
to "7800-B" or whatever. It just stayed "7800"
and switched over to the B version once A stock sold out.
Back then, if you ordered "a 7800 hub (or wheel)!" from a distributor,
there was a period when you had no idea which one would show up. That was annoying.
The successor WH-7801 hub and wheels
only use retainer-type bearings on the anti-freehub side.
As for whether retainer or loose balls is better—
retainer wins long-term, loose balls short-term.
You should not do the modification where you take the ceramic balls out of
a Campagnolo CULT retainer ring, increase the ball count,
and resettle them as loose balls—the so-called "ball CULT" conversion.
I honestly don't understand why that made-up term even exists. Ugh.
It seems like it was used with play for a while,
but the bearing races weren't damaged at all.
The steel balls (Dura-Ace uses stainless) were in excellent condition too,
so I'll grease them up and reassemble.
That's one of the nice things about Dura-Ace hubs—really high durability.
↑The C-shaped spring on the freehub body pawl
looks just like Novatech, not Campagnolo.
Hub-side nipples feel like overkill from a design perspective,
but the person who gets frustrated dealing with them
is me, not the customer, so if it means a better wheel,
I couldn't care less about that kind of minor inconvenience.
Or so I thought...
The rim was drifting toward the freehub side, so to center it
I had to evenly increase tension on the anti-freehub side nipples.
And I mean really increase it.
Those ten nipples in the photo
each turned about three-quarters of a rotation.
Extremely tedious.
I really don't mind this kind of work,
but team mechanics would hate this. Definitely.
It's easy to say "maintenance hassle doesn't matter if performance is good" when you run a shop.
The rear wheel's bearing was shaken up by the play,
so the grease was pitch black,
but the front wheel had no play and the grease kept its original color,
so I just topped it off without cleaning and regreased it.
The front wheel had almost no centering drift or runout,
so most of today's work time went into the rear wheel.