Greasing new wheel bearings and hub.

I fill them. Period. Done it that way forty plus years. Don't really care what the manuals or other "experts" say. When bearings heat up, that heat gets transferred to the grease in the hub and allows some heat OUT of the bearings. If the void was not meant to be filled with grease, it would be a hole just big enough for the spindle to pass through. Think about THAT when you eat your Corn Flakes.