Let's face it: When you tow a trailer behind your vehicle, all you really want to do is get your payload from one location to another with minimal effort. You don't want the trailer to rock and rattle any more than is necessary, and you sure don't want it to slow you down. Luckily, you have a friend in this endeavor: trailer bearings.

You can't see these towing components without dismantling your trailer's wheel assembly, but bearings are in there doing you a world of good. Then back the nut off one notch, so that the cotter pin will fit through the castle nut.

Install the cotter pin and then spin and rock the hub.
When you rock the hub you should feel the hub barely moving front to back.
Try experimenting by loosening the castle nut one more notch to feel the difference in the play in the hub.
Then install the wheel and rock the hub again.
On the outside edge of the tire, the movement should not be more than 1/4" inch.
Any play should be barely noticeable.
When you are satisfied with the adjustment, secure the cotter pin.
Push the pin through the hole on the end of the spindle and through the notches on the nut.

They help to provide a smooth towing ride and prevent friction from slowing you down and unnecessarily wearing out your trailer's parts. Without them, heavy loads could grind wheel movement down to a standstill.

­But bearings require regular maintenance, such as greasing, to keep them rolling. With enough wear and tear, you may even have to replace them. IFinal Castle Nut Adjustment:

To make sure the hub is seated properly, back off the castle nut until it is loose.
Then tighten the castle nut snugly until it stops.
Look to see where the cotter pin hole lines up with one of the notches on the nut.

On hubs that use the tang washer or cage to lock the nut, you will have to do this by sight.f you own a trailer or plan to use one soon, it pays to recognize how bearings work and how to keep them in good repair.

Read the next page to learn just what goes on inside that wheel assembly and what exactly those bearings are doing.The arrival of spring and warmer weather means the start of the trailering season for many drivers, as families break out their boats, campers, and other outdoor gear after a long winter. But before you hitch up and go, it's important to think safety, both in terms of maintenance and once you're on the road.

• Always do a safety walk around before setting out, checking lights, tires, and all connections.
  
• If your trailer is wider than your tow vehicle, you'll need a set of extended side mirrors to see around it.
  
• Two safety chains between your trailer and tow vehicle are a required safety item in case the trailer tongue comes off the tow ball. Anchored to each side of the tongue, they should have enough slack to allow sharp turns without dragging, and should cross under the trailer to form a sling to support the tongue if the trailer separates from the tow vehicle.
  
• Many states require a separate braking system and breakaway switch for loaded trailers with a weight greater than 1,500 pounds. Check with your state department of motor vehicles for local regulations. If your trailer has brakes, make sure they're in good working order. Attach the breakaway cable to the tow vehicle, not to the hitch. That is the importance of trailer bearings.