This post compares the advantages and disadvantages of sealed and unsealed BMX hubs.
The Advantages Of Sealed Hubs
- Protected Bearings
As the name suggests, a sealed hub has sealed bearings. Sealed bearings are protected from the elements and can last a long time without complaining.
- Stay Tight For Longer
A sealed bearing is less likely to develop play. This applies not only to hub bearings but to bottom brackets too.
- No Need For Adjustments
Sealed bearings do not require significant adjustments during a hub assembly. Meanwhile, non-sealed bearings require the user to adjust the retaining locknuts to a setting that allows the hub to rotate freely without having a noticeable play.
- Easier and Cleaner Replacements
If the user has the necessary tools to push out and press in a new set of bearings, the replacement is simple. Also, there is no need to grease the bearings because they’re already lubricated and packed tightly. This makes the process less messy.
- Fewer Parts
Sealed hubs have fewer parts and are therefore simpler to service and less likely to malfunction, at least theoretically.
The Disadvantages of Sealed Bearings
- No servicing
The main disadvantage of sealed bearings is that they can’t be serviced. Thus, they aren’t “recyclable” and should be periodically replaced.
- More expensive
Sealed hubs tend to cost more and are consequently not found on most budget wheels.
The Advantages of Unsealed/Semi-sealed Bearings
- Cheaper and Serviceable
Unsealed hubs cost less and can be serviced for a very long time. The first part that is likely to malfunction are the free ball bearings. However, those can be replaced for cheap.
Servicing loses its incentive when the cup and cone races show significant wear. In that case, it’s cheaper and wiser to replace the entire hub.
Even though hub servicing isn’t the most basic task, any serious cyclist can learn how to do it fairly quickly.
Note: It’s also worth mentioning that unsealed bearings can be serviced in less-than-ideal conditions (e.g., when touring) as long as the rider has the necessary tools (cone wrenches, grease, small pliers or tweezers…etc.)
The Disadvantages of Unsealed Hubs
Dirt and moisture have an easier time entering unsealed hubs. Consequently, the hubs are more likely to underperform when exposed to such conditions.
- Harder to Adjust
Unsealed bearings require adjustment so that the hub can rotate freely without play.
- More Frequent Servicing
Unsealed hubs have to be serviced periodically to keep the smooth rotation and eliminate play. Sealed bearings, on the other hand, are expected to last longer with servicing/replacement.
What to get? Sealed or unsealed?
As long as the hubs are made by a brand with a good reputation both will serve you for a long time.
Of course, the unsealed bearing will require periodic servicing, but it’s good practice to learn how to do it anyway. You will also have to get a few tools (e.g., cone wrenches) to perform the task. Those aren’t expensive and will be useful for various bike repairs.
If you have the extra money to afford wheels with sealed bearings, the investment is fairly justified. However, a decent bicycle with unsealed hubs can be acquired too, and it won’t limit you in your skill development as long as the rest of the components are up for the task.
Another economical option is to get a sealed front hub only. Those are simpler and thus cheaper.
FAQ: Does the above apply to bottom brackets and pedals too?
Yes. The advantages and disadvantages when it comes to sealed and unsealed bottom brackets and pedal bearings are identical.
FAQ: Can I replace my unsealed bearings with sealed ones?
To make a switch from unsealed to sealed hubs, the entire hub will have to be replaced due to structural differences.
To replace the hub, you will have to re-lace the entire wheel. Also, the new hub will more than likely require new spokes of different length.
FAQ: What will happen if I don’t service an unsealed hub?
If an unsealed hub is left unserviced, the ball bearings are usually the first to wear. If the ball bearings are in bad shape, they will slowly damage the cup and cone races. When that happens, the hub is considered non-repairable.
Additionally, the hub will inevitably develop some play over time, especially when it’s on a BMX bike.