Safety Details for Safe Trailering

By Capt. Joan Gilmore


How many times have you seen a broken down boat trailer by the side of the road? Maybe you have experienced a trailer breakdown yourself. Often the problem is not a flat tire but a too-hot wheel bearing. Wheel bearings on boat trailers can get so hot that the wheel can actually get thrown off the axle.


Even if you have already trailered this season, it’s very important to check your trailer wheel bearings, especially if you will be trailering a long distance. You should check early in the season and also when the trailer will be bearing an especially heavy load.


Bearings are packed with either of two types of grease.

  1. Lithium-complex grease is a newer type of grease made for higher temperatures and use in the water.
  2. Calcium-based grease is the older form of bearing grease.


Don’t mix greases! Find out what kind you have and stick to that type.


Make sure the grease you use is marine-grade. If your grease looks milky, you must change it. Just like milky oil in your marine engine, milky grease means that water has gotten in, and the grease must be changed. Typically, grease is changed every 3,000 miles.


A newer lubrication system for trailer wheels uses an oil bath to lubricate the bearings. Originally developed for large semi trailer trucks, these have a handy oil indicator cap that is easy to read.


How should you check your bearings? 

  1. Jack up a wheel. Spin by hand. Your wheel should spin quietly and freely. Do you hear a noise?
  2. Look at your boat after trailering. Do you see grease on your boat hull above the trailer tire? 
  3. Feel the trailer wheel after traveling a short distance. Does the wheel hub feel hot?


If you answered ‘yes’ to any of these questions, you need to service your bearings.


Take care of your trailer for happy, safe boating this summer.