The ball bearings have to be installed per the shop manual. Usually that means if you are going to service them, you clean them until spotless, then repack with fresh grease. The best grease to use is what is commonly described as the fiberious grease that was once sold for ball bearings. The grease is more properly described as a high metallic soap grease. I am not aware of anyone who makes or sells that kind of grease any longer but it turns up on eBay once in a while. Very stringy grease.
Once repacked with clean grease, the bearings get installed into their races, with the hub, and then torqued to specification. This seats the balls into the race and puts a bit of preload on the cages. Then the nut gets backed off a specified amount while the wheel is rotated a bit. Following the correct procedure, including the correct torque specification and back off should give you a good long service life.
This is a bit of what I have of the fiber grease. Sticky, stringy, and melts a bit to keep the balls lubricated. Today’s high temperature greases do not do this.
