Pulling Eagle Ford Trailers Safely – Crack the Whip!

Combination vehicles require a more developed skillset

Pulling Eagle Ford trailers safely is no task for the faint at heart. Combination vehicles are usually heavier, longer, and require more driving skill than single commercial vehicles. This means that drivers of a vehicle combination like a straight truck with a trailer need more knowledge and skill than drivers of single vehicles. These drivers also need a Combination Vehicle Endorsement on their CDL. To get one, you have to take a written test and a skills test. You’ll have to demonstrate that you know how to handle two characteristics of trailers that make driving a combination vehicle more of a challenge than driving a single vehicle. These are:

  • rearward amplification and
  • yaw instability.

Eagle Ford Trailers – Rearward Amplification

In the busy production-driven environment of the Eagle Ford Shale oilfield, “crack the whip” usually means, “get busy, get to work!” For drivers of tractor-trailers, however, “crack the whip” has a different meaning.

Oversteering Photo

Truck Oversteer | Click to Enlarge

Trucks with trailers have a dangerous crack-the-whip effect caused by rearward amplification. A quick lane change can cause the trailer to swing out, then swing back, like the tip of a whip. This effect is most severe in double and triple combinations. The last trailer in the combination will be affected the most. The result can be a rollover.

Steer gently and smoothly when pulling trailers. Maintain a generous following distance. Leave at least one second for each ten feet of your vehicle length, plus another second if you’re going over 40 miles per hour. Look far enough ahead to avoid having to make sudden movements. Drive slowly and make lane changes gradually. Keep plenty of space to the sides of the vehicle so you can enter or cross traffic smoothly.

Truck Understeer Photo

Truck Understeer | Click to Enlarge

Control your speed whether fully loaded or empty. When empty, large combination vehicles take longer to stop than fully loaded ones. When lightly loaded, the very stiff suspension springs and strong brakes give poor traction and make it very easy to lock up the wheels. The trailer can swing out and strike other vehicles.

A tractor can jackknife very quickly. Be careful about driving bobtail tractors which can be very hard to stop smoothly and which take longer to stop than a tractor-semitrailer loaded to maximum gross weight.

When the wheels of a trailer lock up, the trailer will tend to swing around in a trailer jackknife. This is more likely to happen when the trailer is empty or lightly loaded. Stay off the brake. Do not use the trailer hand brake while driving, it can cause a trailer skid.

Once the trailer wheels regain traction, the trailer will start to follow the tractor and straighten out.

Yaw Instability Can Cause a Rollover

“Yaw” means rotation around a vertical axis. In terms of trailers, this vertical axis is the kingpin and it’s where the trailer is joined to the tractor. This connection does not keep the trailer in a fixed, straight line behind the tractor. After all, the whole point of having an articulated vehicle is to create an angle between the tractor and the trailer. That allows the entire rig to take curves and corners.

However, this flexibility can cause problems called “yaw instability” or “snaking.” Sometimes this swaying, or oscillation, can cause a rollover. As the speed at which you’re traveling increases, your trailer or trailers will start to sway from side to side. A sudden steering maneuver can also lead to instability. Several factors can contribute to yaw instability such as:

  • the condition of your tires
  • the stiffness of the suspension
  • the placement of the fifth wheel
  • the distribution of cargo

Load cargo and pre-trip your rig with care. Use caution when passing vehicles on the highway or going around a sharp corner. Don’t understeer or oversteer.

If you have an interests in driving in the Eagle Ford, be sure to visit our South Texas Oilfield Jobs page and Devorah’s website linked in her bio below.

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Devorah Fox, President - Mike Byrnes and Associates, Inc Authors of BUMPERTOBUMPER®, The Complete Guide to Tractor-Trailer Operations and the Easy CDL iPhone apps, Mike Byrnes and Associates, Inc. has helped launch successful commercial motor vehicle operator careers since 1987.

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