Bearings
should never be installed by pressing on the inner
race or rubber seal.Press with an appropriate tool
,only making contact with the metal of bearings outer race.
The bearing aperture must be clean with no rough edgers or burrs.
Bearings that feel smooth before fitting, but then feel rough or gritty after fitting,
are almost always due to the cartridge being poorly seated
If the bearing cartridge starts to twist ,under no circumstances
should you continue to install .Stop, gently remove, then re-install.
Even a slight twist can damage the bearings inner races irrevocably.
--- After care ---
For bearing longevity, do not direct a jet of water ,or powerful
grease cutting detergents, toward bearings
( BBs, wheel hub, headsets etc )
water penetration can lead to premature bearing failure.
For service and lubrication
related item links ;