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How Trailer Towing Safety Works

Connecting a Trailer for Towing
Even in light traffic, avoid speeding while towing a trailer.
Even in light traffic, avoid speeding while towing a trailer.
Tim McCaig/iStockphoto

Before you hook up a trailer to a tow vehicle, you need to take the following into consideration:

  • How much weight can the tow vehicle pull safely? This information should be in your owner's manual.
  • How much weight can your trailer hitch and ball mount handle (tongue weight)? You can adjust tongue weight either by using a weight-distributing trailer hitch or by balancing the load inside the trailer itself.
  • How much weight can the trailer carry safely? Manufacturers set weight ratings for trailers. Exceeding this limit is unwise -- you could risk equipment failure.
  • How much will the trailer weigh when loaded? This is called the gross trailer weight (GTW). The maximum weight of the trailer and tow vehicle combined is the gross combination weight rating (GCWR). Again, it's unwise to exceed this manufacturer-recommended weight limit. You can weigh your vehicle and trailer on a public scale.
  • Is the load inside the trailer balanced properly? Are the items inside the trailer secure? Unbalanced loads can cause problems like trailer sway on the road.
  • What are the local and national laws you'll need to follow? Some areas have strict laws regarding trailer size and weight. Make sure you research these laws before you leave home.

With that out of the way, let's look at the process for connecting a trailer. The coupler on the tongue of the trailer should fit over the ball on the trailer hitch ball mount. Make sure the equipment matches up -- if the trailer's coupler doesn't match up to the ball on the ball mount, you can't tow with that trailer safely. The coupler should have a securing device that you'll need to lock into place. This prevents the coupler from detaching from the ball mount.

You should then attach safety chains to the trailer tongue and your trailer hitch. The chains should cross underneath the tongue of the trailer. That way, should the trailer break away from the hitch, the chains will be able to support the tongue. Make sure you leave some slack in the chains -- tight chains will inhibit your ability to make turns.

Some trailers -- in particular larger trailers that can haul more than 1,500 pounds (680 kilograms) -- have braking systems. There are two major kinds of brake systems for trailers: surge brakes and electronically-controlled brakes. Surge brakes are hydraulic brakes that have an activation switch located in the trailer tongue. Should the trailer tongue break away from the trailer hitch, the switch activates the brake system. Electronically-controlled brakes connect to the tow vehicle's electric system. The driver can activate electronically-controlled trailer brakes using a hand control located within easy reach of the driver's side -- usually on the console itself.

Many trailers have electric systems. Trailers use connectors to plug into a tow vehicle's electric system. New basic trailers might have a simple four-way connector. Each connector controls a different function. A four-way connector could supply power and control to taillights, brake lights, turn signals and side marker lights. Some newer trailers and tow vehicles can take advantage of seven-way connectors, which may also provide power to a trailer power supply, braking system and backup lights. If the connector on your trailer doesn't match up to your vehicle, you can use an adapter to solve the problem.

Once you've connected your trailer to your tow vehicle and checked to make sure everything is safe and secure, it's time to hit the road.