Use what the mfg recommend. Also carefully inspect the races and bearings for pits, abrasion, discoloring and etc. Replace any faulting bearing and its race. Torqueing the bearing properly is very important to achieve long Gevity and is more important than the grease selected. If you have Easy lube axles, use tang type keepers rather than the springing nut retainer things the most mfg.s use. The spring things are unreliable and have a tendency to loosen which will cause premature bearing failure. Any noticeable looseness is a bad thing.