Keeping Bearings And Brakes Tight

Helping your wheel bearings roll along smoothly and keeping your brakes tight will make your boating life easier and safer.

Photo of oil can and gearsPhoto: Thinkstock

Bearing Grease & Bearing-Protector Grease: Two Different Functions

Photo of a can of wheeling bearing trailer grease Photo: Billy Black

All wheels (axles, spindles, bearings) need clean lubrication to function properly. Trailer wheels are fundamentally different from car wheels or truck wheels in two ways: They sit for long periods between trips then carry heavy loads, and they routinely get dunked in seawater. Speeding down the highway generates heat; dunking in water induces cold; the difference creates a vacuum. Bearing protectors (Bearing Buddy and others) use grease to apply positive pressure to the bearing seals, preventing vacuum pressure at launch time from drawing water, grit, and salt into the bearings. But many boat owners confuse the grease for the bearing protector with the grease for the bearing itself. Not the same! A bearing protector typically has a zerk fitting; before every launching, check the protector and, if necessary, load it with grease until its piston pops out. However, doing this doesn't diminish the regular maintenance cycle for the bearing itself. Every season or every 2,000 miles, take off the wheel; clean the bearings with a solvent such as kerosene; check for pitting, discoloration, or other damage; and repack bearings with the new grease.


Surge Brakes: When inspecting surge brakes, check wheel cylinders, brake lines, and the master cylinder for corrosion and fluid leaks. In addition to changing out your brake fluid annually, also check the brake fluid level before each trip and regularly inspect the fluid itself for rust, sediment, or water contamination.

Surge-Brake Adjusting: Surge brakes must be adjusted periodically. You'll have to jack the wheel off the ground and use a tire tool to first tighten the adjustment cog all the way until the wheel won't turn, then back it off a few turns until the wheel again turns freely. If you do the job yourself, follow the manufacturer's recommendations.

An Ounce Of Prevention (Or Penetrating Oil)

You may not be changing your bearings this year, but you should still go through the motions of removing each wheel, or at least the lug nuts. You may find that when you go to remove the lug nuts, they'll be corroded and difficult to remove. It's not uncommon to find that when you stand on the lug wrench to try and loosen the nuts, you'll break the studs. You don't want to find yourself on the side of the road with broken studs (or in my case, three broken studs). Take the time to spray each lug nut with penetrating oil, and let them soak a bit. If you're still unable to remove the nuts at this point, take the trailer to a garage where they have an air-powered impact wrench. Loosen and remove each nut, spray the stud with the penetrating oil, then reinstall the nuts.

Trailer Tires: Cracking The Code

If you need to replace the tires on your trailer, it's useful to know what you're looking for Trailer tires aren't like car tires. This photo shows a typical description for a trailer tire: "ST 205 / 75 D 14." What does that mean? Well, that code contains five discreet kinds of information:

  • The "ST," for special trailer, is the tire type. Other designations are "P" for passenger and "LT" for light truck. ST tires are more durable and resist abrasion better than other tires. Using P or LT tires will cause your trailer to bounce and fishtail more on the road. If you must use P tires, downgrade the load capacity by 10 percent.
  • The "205" is a measure of the tire's section width, in millimeters.
  • The "75" is the tire's aspect ratio: the tire's section height divided by its width. Tread width decreases as aspect ratio increases.
  • The "D" refers to the tire's construction and denotes a bias-ply tire. Other symbols are "R" for radial and "B" for bias belt.
  • The "14" refers to rim diameter, in inches. This figure is an important one if you need to replace a blowout.

A general note about trailer tires: The larger the diameter, the fewer revolutions per distance, meaning less heat, less tire wear, and less bearing maintenance.

Don't Mix Tire Types

When replacing tires, never mix and match different types (bias ply and radials, for example), and use only tires designed for use with boat trailers — they're typically more expensive, but have thicker sidewalls and are more robustly constructed.

Bearing A Spare With Bearings

As a rule, wheel bearings fail at the worst possible time and location, typically a crowded freeway with 100-degree temps, or some out-of-the-way area. The quickest, simplest way to handle this situation is to carry a spare tire with hub and bearings already installed. Short of that, carry spare bearings and all of the paraphernalia to both remove the old ones and install the new. 

— Published: Fall 2014


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