TOPIC:

oil is a better lube for roller bearings  but are not with out service requirements  /  changing the oil. they are very intolerant to leaks or running low on oil and contamination. grease is messy and shows there is a problem way before there is a failure. hard to ignore grease all over a wheel or the side of your boat.  greased wheel bearings have been around long time and most experienced boaters either know how to take care of them or know where and when to have them taken care of . oil bath bearing are relatively new to the trailered boat world and most owners don't realize till its too late what needs to be done to properly care for them