Jun 16, 2011
5 Common Trailer Use Mistakes
Many fleets use trailers to move heavy equipment and supplies from place to place. Here are some common mistakes concerning use of trailers from Business Fleet and lead trailering engineer for General Motors Co., Robert Krouse.
1. Failure to calculate the actual weight of the trailer
Krouse points to landscaping trailers as a good example of how operators can misjudge the weight they’re asking their trucks to pull. The weight of the equipment inside may seem insignificant compared to the trailer itself, but it’s a principal factor in determining whether your equipment is pushing the load past your tow vehicle’s capacity.
“Retail or commercial, the same principles apply,” Krouse says. “The ratings are based on weight, and that’s what we go by.”
It’s crucial to weigh your loaded trailer at the nearest available scale before towing it. Also check to be sure the trailer’s tongue weight — the downward force exerted by the trailer’s “tongue” — is within your hitch’s rating.
2. Failure to account for the actual capacity of the tow vehicle
Now that you know how much weight you’re pulling, you just have to check that against your vehicle’s trailer weight rating (TWR), right? Not so fast, Krouse says. Pulling your truck’s rating from the Web might not provide the right number. Many manufacturers only provide each vehicle’s maximum TWR, which may depend on a particular engine or nonstandard equipment.
Your dealer or factory rep should be able to provide your vehicle’s TWR and information on how to upgrade it. Once you have the right number, be sure to add the weight of your truck — including people in the cabin and equipment in the bed — to the weight of the loaded trailer. If that figure surpasses the vehicle’s gross combination weight rating (GCWR), you’re past the point of a safe tow.
3. Overloading the trailer or tow vehicle
Failing to determine TWR and GCWR are the most common weight-rating pitfalls, but there are several other factors to consider. Krouse says that tow vehicle and trailer gross vehicle weight ratings (GVWRs), individual tow vehicle and trailer gross axle weight ratings (GAWRs) and individual tire ratings are just as important.
There’s also the trailer tongue weight, which can differ from your hitch’s rating. Failing to note any of the factors listed earlier can result in damage to the tow vehicle or trailer, not to mention excessive wear on your brakes or tires.
4. Improper setup
Now that your tow vehicle, trailer and combination weights and ratings are within range, the next objective is a proper coupling. If your hitch ball sits too high or low or your sway controls and weight-distributing spring bars are improperly adjusted, you still run the risk of damage somewhere along the setup.
To be sure the trailer load is properly balanced, for a weight-distributing hitch setup, Krouse suggests measuring the space between the top of the tow vehicle’s front tire and the bottom of the fender. That space will increase once the trailer is coupled; adjust the spring bars to get back to the initial measurement without decreasing it.
Each state sets its own standards for trailer brakes, but Krouse recommends adding a brake controller whenever you’re pulling 2,000 lbs. or more. In an electric system, a signal is sent to the trailer brakes when the tow vehicle’s brakes are applied, engaging them in unison. Several manufacturers, GM included, now offer a factory-equipped brake controller on most models.
Another option is a hydraulic brake controller, also known as a surge brake. Surge brakes employ a self-contained apparatus in the hitch that engages the trailer brakes when the tow vehicle slows down.
5. Improper road protocol
Krouse sums up his advice for driving while trailering in one word: practice.
“The operator always has to realize, it’s not like driving the tow vehicle by itself,” he says. “Don’t ever let that become back-of-mind.”
Turning, stopping, backing up, merging and changing lanes all require more time and space. There’s no substitute for practicing those maneuvers in an open area before hitting the road, and remember to adjust your mirrors to the length of the trailer. GM and other manufacturers offer extendable side mirrors as a factory option.
Finally, special attention must be paid to maintenance when your pickup is pulling heavy loads. Krouse lists fluids, tires and brakes as particular areas of concern. The trailer’s own brakes and tires also should be checked frequently, and trailers that sit idle for long periods should be inspected before they go back on the road.