Bicycle Mechanics - Sealed vs Unsealed (Headset)???

I understand the difference between "threaded" and "threadless" (headset), but what is meant by "sealed" and "unsealed"???

Sorry for the dumb question, but I'm just now trying to teach myself more about bicycle mechanics.

Headsets are made with two types of bearings, loose ball (often in a retainer cage) or cartridge bearings.

The "seals" in loose ball headsets are just rubber gaskets or O-rings that make a half-hearted attempt to keep out water and dirt.

Cartridge bearings can be fully sealed or shielded which is a semi-seal. A big advantage to cartridge bearing headsets is that the bearings contain the races in the same unit so a worn out bearing can be replaced without pressing out the cups or crown race.

A sealed headset looks like this:


http://lizardskins.com/images/pages/products/small/22.jpg

A big advantage to cartridge bearing headsets is that the bearings contain the races in the same unit so a worn out bearing can be replaced without pressing out the cups or crown race.

Eh? With loose ball, you don't need to press out the cups or crown race either.

A sealed headset looks like this:




Never seen a King?

http://i144.photobucket.com/albums/r181/cyccommute/Las-Cruces-head.jpg

That's sealed;)

Never seen a King?

That's sealed;)
My solution to seal the headset costs $3, what about yours?

My solution to seal the headset costs $3, what about yours?

Oh, much more. But they are very smooth, last forever and are very pretty. Already transfered some of the 4 :eek::eek: I own from other bikes...some more then once;)

Eh? With loose ball, you don't need to press out the cups or crown race either.
You do after the crown race and/or lower cup are "brinelled" (i.e. pock marked) after some use and it WILL happen sooner or later. With cheap headsets it's sooner.