This post compares the advantages and disadvantages of sealed and unsealed bicycle headsets.
What is a sealed headset?
The headset of a bicycle is a system of bearings and cups that allow the fork steerer to rotate smoothly inside the frame’s head tube. As the name suggests, sealed headsets rely on sealed bearings that have non-visible ball bearings inside of them.
What is an unsealed headset?
An unsealed headset uses standard caged ball bearings that the user can see and lubricate. Unsealed headsets have been the norm for a long time, but unsealed models are quickly gaining popularity.
The Advantages of Sealed Headsets
- Protection from Moisture and Dirt
The main advantage of sealed headsets is that the bearings are protected from dirt and moisture by the seals. As a result, the bearings can operate smoothly for a long time without having to replace them. (Sealed bearings are not meant to be serviced.)
The Disadvantages of Sealed Headsets
Once a sealed bearing shows signs of wear, the only fix is to replace it. Attempting to service a sealed bearing would hurt the seal and put the unit out of alignment. Given the price of a new bearing, it makes little financial sense to experiment with repairs.
- Less common and More Expensive
The short history and the low demand make sealed headsets more expensive.
The Advantages of Non-sealed Headsets
A non-sealed headset provides access to the bearings. The bearings can be easily cleaned and re-greased to keep them running smoothly. If they’re damaged, the user can replace them with an equivalent unit of the same size.
As a result, a non-sealed headset can last a long time. However, once the races on which the bearings run get damaged, it’s time to replace the entire headset.
- Cheap and Readily Available
Non-sealed headsets have been the standard throughout most of cycling history. Consequently, one can find them everywhere and for a relatively low price.
The Disadvantages of Non-Sealed Headsets
- Exposed Bearings
The bearings of non-sealed headsets are exposed and prone to contamination. Additionally, they have to be greased by the user during service. The process isn’t complicated, but it’s easy to put grease on other parts of the headset and make a mess.
FAQ: Which headset offers the smoothest rotation?
They’re both on par with each other. In practice, one would be hard-pressed to tell the difference between a well-maintained non-sealed headset and a sealed one, especially during dynamic riding.
The value of sealed headsets is not a smoother rotation, but a smooth rotation for a longer period of time without intervenience from a mechanic.
FAQ: Can I combine sealed bearings with a non-sealed headset?
No. The cups and the bearings will not “agree” with each other. If you want to switch from a non-sealed headset to a sealed one, the process is as follows:
- Remove the fork from the bike.
- Remove the bearing races and the cups. (You will need a headset removal tool and a mallet. You can also make your headset cup removal tool from an old seat post.)
- Remove the crown race from the fork.
- Measure the top and bottom entrances of the head tube (they will be different if the head tube is tapered.)
- Find a sealed headset matching those dimensions.
Is it worth it?
The headset is an important component, but switching from an operating non-sealed headset to a sealed one will not result in a perceivable performance difference.
If your sealed headset is giving you problems, usually one of the following will work as a solution:
- Repack the headset (if the headset is loose).
- Clean the headset and re-grease the bearings
- Replace the bearings (if the above doesn’t solve the problem).
- Replace the entire headset with a sealed or non-sealed one (last resort).
Summary: What You Need To Know
- Sealed headsets provide protection from the elements and are expected to last a long time without having to replace them.
- The bearings of sealed headsets cannot be serviced. Instead, they’re replaced when needed.
- Unsealed headsets have semi-sealed bearings that get contaminated faster and require maintenance (cleaning and greasing).
- Unsealed headsets will last a long time if serviced. The first problematic segments are usually the ball bearings. Those are cheap to replace.
- Neither of the headsets is inherently superior when it comes to performance.
- The transition from non-sealed headset bearings to sealed ones requires the replacement of the headset with a sealed one.