Stopped on the shoulder, with acrid smoke pouring from a trailer wheel — it’s not a fun place to be. With a bit of preventive maintenance, there’s a good chance you’ll never have to deal with a highway meltdown. Keep your trailer bearings well-greased and they will last all season — or perhaps several if you don’t tow far and often. Sooner or later, however, it’s time for a replacement. Some will choose to farm this task out, because it can get a bit messy dealing with wheel grease. But it’s a task well within the grasp of the average DIY boater; just keep plenty of shop towels and some degreaser handy, and put a dropcloth or old cardboard box under the work area.