dikiw@mmintl.UUCP (Diki Wozniak) (08/08/85)
Sealed bearings can mean different things to different companies. The usual meaning is that the bearings are held in a integrated shell that has sides. Thus when you take the bearing out you are holding a little donut that spins around. Examples of this type of sealed bearings are found in Bullseye, Specialized hubs and I believe the newer stuff from Sun Tour and Shimano. These bearings do wear out, but it usually takes a long time. The idea is to keep solvents away from them so the seal is not broken. You can take some sealed bearings apart and rebuild them but the usual practice is to replace them, as they are a standard item and inexpensive. There are various grades that I used to know when I was into Skateboarding (roller skate wheels use them too) but I don't remember the system. The other type of sealed bearings are really sealed components, and the only person that come to mind is Phil Woods. Basically a phil hub or bottom bracket is put together to stay together. It is not a user serviceable part. Special tools and presses are needed. The idea is that it is so strong that it never needs service. Extremely Macho. I know people who love phil stuff and others who say that Bullseye or Specilized is better because everything breaks eventually. I would be interested in hearing from any netters with experience with these parts, I was thinking of building some city wheels for my Mountain Bike using Phil hubs and Z rims (zytel nylon BMX part, will not bend...I have seen a picture of Mike Buff riding a 20" bike off of a garage roof into the backyard...) and possibly Zeus foam tubes. Some unscupulous types call any bearing that has a dust shield between it and the road "sealed". Almost every bottom bracket is sealed in this way, but when you open it up it's little balls all over the place Hope that your not too much more confused than when you started reading Aloha