What are sealed bike bearings?
Seals commonly sold at bicycle stores are not typically built to be water-resistant. This kind of seal is instead simply modeled to prevent air from entering the bearing. Sealed bearings are then bearings safeguarded by seals, and these bearings are found in hubs and bottom brackets. Not only is a sealed bearing self-enclosed, but it also keeps necessary lubrication locked inside.
When some people say sealed, they may be referring either to the cartridge or the cup and cone bearing, with a labyrinth seal or a rubber seal. The cup and cone bearing helps to prevent dust from entering, but they offer no protection against water. These makes are generally easier to maintain on the road and so replacing them is relatively cheap.
On the other hand, cartridge bearings are more expensive initially, but maintenance is typically cheap. The balls do not need to be replaced, and neither does the surface require regular cleaning. You can use the unit until it becomes rough, and even then, you can replace it for a small amount.
Both cup and cone and cartridge bearings on current quality bicycles are typically sealed. However, the seals do not guarantee water or dirt will never enter – even well-sealed bearings could be compromised if exposed or submerged in water, as in the scenario of heavy rain or washing your bike. The most effective seal is in fact two seals: a contact seal nearer to the bearing and a second seal further out.
It is essential to note that cleaning a sealed bearing is more complicated than cleaning an unsealed one. A disadvantage that the cartridge has is that there are more specific tools required for maintenance.
Sealed Bearings in an Unsealed Hub?
When it comes to bearings and hubs, most often you’ll find that the cups cannot be removed – although you may find some on aluminum hub shells.
In the uncommon models where cups are removable, you will need bearings with diameters that match – usually 10 mm for both the inner and outer diameters. If the sealed bearings have the exact diameter as the hub, then it might be possible to add to an unsealed hub. If both are of different dimensions, you will find it quite impossible.
Sealed vs. unsealed hubs
Unsealed hubs possess loose bearings, while sealed hubs have bearings identical to an integrated headset as they are in covers and cups. You can also cover an unsealed hub.
Sealed hubs roll smoother, last longer, and are very easy to maintain. The name “sealed hubs” mostly refers to cartridge hubs. In a sealed hub, the bearing is sealed within a flattened ring that functions as the bearing race. Most renowned manufacturers use these hubs. If the hub is well arranged, you will have a dependable unit that can be repaired easily and last you a lifetime.
Can you put sealed bearings in an unsealed hub?
To come back to the question, such a task would be near-impossible. Apart from having matching diameters on your bearing and hub, you would also need an axle with the precise length for the inner race, a hub shell, and a lock nut of the right length.
The good news is, a sealed bearing and hub wheelset can be easily purchased and does not have to break the bank. If you prefer to use a sealed bearing, this would be your best option.
Credits and Useful References