Sealed bearings.
These are parts commonly used in bicycle components.
Whether it's the rotating part of a hub,
the moving part of a brake lever,
or even deeper inside the pulley of a derailleur,
sealed bearings of various sizes are used throughout a bicycle.
The advantage of these sealed bearings, compared to retainer bearings, is that the rotating internal parts are protected by a seal, which keeps out dirt and water, allowing them to be used for a long time without maintenance.
"Used for a long time without maintenance???"
That's right.
To put it another way, the reality is that they cannot be maintained.
You might see things on the web about "removing the seal, cleaning it, adding grease, and restoring the rotation," but for most sealed bearings, removing the seal is fundamentally a no-go.
Once you remove a seal, it will inevitably be deformed to some extent, so putting it back will never restore 100% of its original rotation.
Therefore, the correct approach is not to put them back, but to replace the bearing itself.
As industrial parts, you should be able to get them for a few hundred yen each if they are standard-compliant.
There are almost no bearings like Chris King bearings that are designed to be serviceable even though they are sealed.
This alone shows just how excellent King's bearings are.
Well, let's leave that topic for another time.
This time, since I have disassembled a sealed bearing—which is basically not meant to be disassembled—let me show you the inside.
Both of these are bearings that were used in PHILWOOD hubs.
Please forgive the fact that the insides are a mess, as these were removed for replacement.
It's interesting that even though they were used in the same hub, one is completely rusted and the other is caked in sludge.
The degree of deterioration varies depending on the environment in which they were used.
By the way, the reason why Phil Wood hubs, which pride themselves on solid and robust construction, are heavy is not just because they are made to be durable, but also because they were designed to withstand the repeated replacement of sealed bearings. That is precisely why they have earned the deep trust of messengers and long-distance tourers.
I went ahead and cleaned them, and when you look straight down into them...
The inside looks just like a stargate.
Now, these bearings have served their purpose.
They will be replaced with new bearings, but because of their structure, most sealed bearings are press-fitted into their respective components, so it's not a simple one-touch replacement process.
Since they often cannot be replaced easily at home, please feel free to consult with us when you need a replacement.
Because they are sealed, it can be difficult to tell when they need to be replaced or if they are malfunctioning, so please don't hesitate to ask if you're concerned.
The smooth rotation of sealed bearings is the secret to smooth riding, so please check them on your next day off.