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Slide the left side washers, spacers and cone on first, then the right, and tighten everything finger tight. Lay the wheel back down bearings on its right side, slide the cone-wrench on, then slide the 17 mm open-end wrench back on and tighten clockwise. Reinstall the rubber seal, and put the wheel back on the bike.

Impact loading which results in a loss of compression will destroy the ceramic balls almost instantly. Ceramic expands less than steel - and much much less than aluminum with increasing temperature. As alluded to above, they are not very good for low speed applications (all bicycle applications are low speed). If you are professional road racer, and your mechanic adjusts the bearing preload every day based on the expected ambient temperature - they are okay, and may be worth the weight reduction. 

Bicycle bearings should last for years and provide you with thousands of miles of travel---but they won't last forever. In some cases they even fail completely if they haven't been maintained correctly. Part of a maintenance schedule should include replacement of wheel bearings before they fail. The procedure isn't that difficult if you have about an hour and a few small tools. Front and back wheels are similar in procedure to change fag bearings and only require slightly different tooling.

Take the wheels off the bicycle beef before greasing the wheel bearings.A mixture of 50 percent white teflon bicycle grease and 50 percent green axle grease works well on bicycle bearings.Don't make the bearing cone too tight when screwing it back into place. Bicycle bearings shouldn't have any play in them and need to roll smoothly.

Bicycle bearings, as most, require a slight preload so that more than one ball under the cone (inner race) will support its load. With proper preload, slight drag should be perceptible. Preload drag is small compared to drag caused by wheel loads, neither of which are significant regardless of adjustment. In contrast bearing life is affected by proper adjustment. Adjusting ball bearings to spin freely unloaded does not reduce operating friction because a bearing with proper preload has lower drag when loaded than one with clearance. For high quality bearings, preload should be just enough to cause light drag when rotating the axle between thumb and forefinger. Low grade koyo bearings will feel slightly lumpy with proper preload.

This is later. Bicycle bearings come nicely snug into crowns these days, but sometimes you still find some that are just put loose in the wheel hub. To avoid all of them crashing to the ground with the possibility of vanishing for ever, grab the axle on the side that is still locked in place and point the end that you've just loosened,up. Now it is time to unscrew the locking nut almost completely off the axle. Next, unscrew the bearing cone to expose the wheel bearings to the light of day. Any grease in there? You'd be surprised on how often I open up brand new bikes and find almost nothing.

The wheel [bicycle bearings]  sit between a cone screwed to the wheel axle and the cup in the wheel hub. They must be properly adjusted and greased. To find out if everything is ok without taking everything apart, simply remove the wheel from the bike and turn the axle with your fingers.