A customer dropped off a Dahon front wheel for me to work on.
The hub bearings were clearly shot,
and when I mounted the hub to the front fork,
there was so much play at the tire end
that the wheel was basically unrideable.
To get the bearing dimensions,
I stripped out all the components from the hub body.
It's an ETRTO 406mm 20-inch wheel with an aluminum rim,
laced with 4 straight spokes in JIS pattern,
but because the hub flanges are thick and it's woven in a final cross,
the spoke paths have quite a bit of deflection.
Not relevant to this repair, but
I'm thinking radial lacing might've been better.
↑From top in the image:
Allen key style quick release
Hollow axle pipe inside the hub body that supports both bearing inner races
Left and right bearings
Press-fit left and right hub ends
Both bearings were bad,
but this was the worse of the two.
As you can see, the inner race isn't centered relative to the outer race.
The inner race isn't fixed in this position—
it's rattling around loosely.
The bearing seal shows HAXB,
which is a Chinese bearing manufacturer.
When I measured the outer diameter with calipers,
it came out to about 15.9mm.
That's when I realized—
these are inch-sized bearings, not metric.
In addition to the manufacturer name, there was an R4 designation.
That's the bearing size standard.
R4 has an outer diameter of 15.875mm (5/8 inch)
and an inner diameter of 6.35mm (1/4 inch).
I thought the width was 5mm,
but it turned out to be 4.978mm.
After looking into it,
I found a bearing with
2RS (dual rubber seal) rather than
ZZ (metal seal),
rated ABEC 3,
but thinking there might be something better,
I kept searching and found one claiming to be ABEC 5
at about the same price as the first option,
so I ordered that one instead.
With new bearings in hand,
I reassembled the hub components.
The title "A Sound Out of the Ordinary" actually has nothing to do
with this front wheel repair.
The customer who brought in this front wheel
told me that his wife
has a rim brake road bike, and to make the braking better,
he fitted an R-SYS brake with an Exalt braking zone.
But apparently it turned out unpopular for some reason,
so they stopped using it.
The reason being that distinctive "kyuu~uu" squealing sound
that the brakes make—every single dog they passed
on their rides would immediately react, turn to look,
and stare at them with alert, wary eyes.
That's why they gave up on it.
The hub bearings were clearly shot,
and when I mounted the hub to the front fork,
there was so much play at the tire end
that the wheel was basically unrideable.
To get the bearing dimensions,
I stripped out all the components from the hub body.
It's an ETRTO 406mm 20-inch wheel with an aluminum rim,
laced with 4 straight spokes in JIS pattern,
but because the hub flanges are thick and it's woven in a final cross,
the spoke paths have quite a bit of deflection.
Not relevant to this repair, but
I'm thinking radial lacing might've been better.
↑From top in the image:
Allen key style quick release
Hollow axle pipe inside the hub body that supports both bearing inner races
Left and right bearings
Press-fit left and right hub ends
Both bearings were bad,
but this was the worse of the two.
As you can see, the inner race isn't centered relative to the outer race.
The inner race isn't fixed in this position—
it's rattling around loosely.
The bearing seal shows HAXB,
which is a Chinese bearing manufacturer.
When I measured the outer diameter with calipers,
it came out to about 15.9mm.
That's when I realized—
these are inch-sized bearings, not metric.
In addition to the manufacturer name, there was an R4 designation.
That's the bearing size standard.
R4 has an outer diameter of 15.875mm (5/8 inch)
and an inner diameter of 6.35mm (1/4 inch).
I thought the width was 5mm,
but it turned out to be 4.978mm.
After looking into it,
I found a bearing with
2RS (dual rubber seal) rather than
ZZ (metal seal),
rated ABEC 3,
but thinking there might be something better,
I kept searching and found one claiming to be ABEC 5
at about the same price as the first option,
so I ordered that one instead.
With new bearings in hand,
I reassembled the hub components.
The title "A Sound Out of the Ordinary" actually has nothing to do
with this front wheel repair.
The customer who brought in this front wheel
told me that his wife
has a rim brake road bike, and to make the braking better,
he fitted an R-SYS brake with an Exalt braking zone.
But apparently it turned out unpopular for some reason,
so they stopped using it.
The reason being that distinctive "kyuu~uu" squealing sound
that the brakes make—every single dog they passed
on their rides would immediately react, turn to look,
and stare at them with alert, wary eyes.
That's why they gave up on it.