I had them on my Pontoon Boat trailer, 28 ft.
I was religous about watching the bearings because of being immersed while still warm.
Have to watch so they have some grease but not so much to push the metal diaphram all the way out.
Still had to replace bearings on one side. I noticed one steaming. The bearing was bad, really bad. Chinese junk.
Too much grease and there go the shoes.
This is a question you didn't ask but I would see about replacing the bearings with permanent lubes ones like were on our Holiday Rambler Fifth wheel. Never got hot nor gave any problems. didn't have to lube them or worry about that.