| I don't know about bottom bracket sealed bearings, but I do know about the
hubs.
According to Sutherland, the bearings in sealed cartridge hubs are as
standardized in the Mech Eng. business as the DIP package is in the
electronics business. It might be worth it to look under "bearings" in the
phone book. Walk in with the old bearing and ask if they can match them.
The outer races are press-fit into the hub. To replace them, you tap them
out with a hammer (this trashes the races however) and put the new ones in by
using specially shaped washers and the locknuts. The washers are shaped such
that the only push on the outer part of the bearing, and when you tighen them
together, they press the bearings into the hub shell.
Before you go to the trouble of taking the bearings apart, first try to
determine if it really the bearing that has gone bad. With the cartridge out
of the bottom braket shell, twist them carefully in your fingers. If they
feel really sticky or lumpy then they might be bad, else check that the
supporting parts are attached well.
It is possible (on the hubs at least) to take off the seal if it's the rubber
kind. Take a thin knife and slide it under the inside edge of the seal until
it pops out. You can then clean and repack. (I learned about this after
riding my hubs through 24" of water in Sudbury last April. It seems that they
aren't really sealed bearings.)
I'm not familiar with exactly how the OMAS BB is put together, but in general
there is one thing to watch out for in all cartridge type bearings: MAKE SURE
THAT ALL LOADS ARE IN THE RADIAL DIRECTION. Don't tighten nuts down so that
there is a sidways load on the bearings. Sutherland says that a misaligned
bearing will wear out faster than an unmaintained "normal" bearing.
-Jeff Bell
|
| If it backed the cup out of teh bb it could be that it came loose.
The OMAS is adjustable on both sides. The bearings should be the
same as anyone else's bearings and you can get replacement "at
good bike shops anywhere -- as I recall the OMAS is not "sealed"
like a Phil Wood but rather like most "sealed hubs", it's just a
labyrinth seal.
I have a friend in Merrimack who has used OMAS bb's for years,
he might even have some extra parts or hints. I'll give you his
# if you call me (381-2377). He's not listed so I won't put it
into a notes file.
ed
|