I’ve written about the first three concepts in previous posts. If you haven’t read my blog post about Arrow Awareness I recommend that you start there.
Kingpin pressure is a natural progression of Arrow Awareness. Once you become acutely aware of where your trailer is pointing at all times, and know where the pivot point is, you can really begin to master your trailer’s movement. Kingpin Pressure is how we redirect the “arrow”. The kingpin is the handle by which we precisely aim the arrow.
How you perceive the tractor and trailer in your mind is critical to your success or failure.
Many students struggle with backing because of some basic misconceptions. By carefully observing student’s behavior and asking them questions about their thought processes, I have learned the causes of many struggles.
Most new drivers over focus on the rear of the trailer and the steering wheel. One of the most crippling problems I encounter is “Opposite thinking”. Opposite thinking is believing that you can make the back end of your trailer move to the left or right by simply turning the steering wheel in the opposite direction. Unfortunately its not quite that easy. This may appear to work when the tractor and trailer are nearly in line with each other. But it is really just an illusion. Once the tractor and trailer become offset from one another this will no longer come close to working. Your backing attempts will fail.
These failures cause frustration and rob new drivers of their confidence. They tend to blame themselves instead of the faulty method.
Here’s a little secret:
An experienced driver is never trying to move the back of the trailer directly when he or she turns the steering wheel. They are consciously trying to move the front of the trailer.
So, my goal here is to get you to start visualizing the trailer differently.
You should always see the tractor and trailer as two separate units. You will learn to control your trailer more quickly and efficiently if you perceive it as a separate unit.
Focus less on the rear of the trailer and focus more on the trailer as a Whole.
In order to master your trailer’s movement you must know exactly how it moves.
The Two Types of Trailer Movement
The trailer is capable of moving in two directions simultaneously.
I will refer to these as Lengthwise and Rotational movement.
This simply involves moving in a straight line in the direction the trailer is currently pointing. This is why I constantly preach to my students to try and develop a constant awareness of where the trailer is pointing. Because where it is currently pointing is exactly where it is currently going.
Rotational movement involves moving in a circle around the trailer’s pivot point—the back tandems.
The tractor and trailer are two separate units connected at the kingpin. You should always see them as such.
There is no direct connection between the steering wheel and the back of the trailer.
So, if you want to influence the back of the trailer you must first go through a “middle-man”. That middle man is the kingpin.
Other than a couple of airlines and an electrical cord, the only place the tractor contacts the trailer is at the fifth wheel. The fifth wheel holds the kingpin.
Any move your trailer makes is a direct result of how your tractor pushes against the kingpin.
Pressuring the kingpin at 0 degrees— Maximum Lengthwise movement. No Rotational movement.
There is no offset and the tractor and trailer are perfectly inline with each other. The tractor will be pushing against the front part of the kingpin and traveling straight backwards.
Pressuring the kingpin at 90 degrees— No Lengthwise movement. Maximum Rotational movement.
The tractor is pushing against the side of the kingpin. Be careful here! You should minimize your time at the side of the kingpin. Because of the properties inherent to the Offset Law you could jack knife very quickly. If your tractor goes beyond the 90 degree point you will actually start pushing the trailer forward as you back up. This will cause damage to both units and should be avoided at all cost.
Pressuring the kingpin between 1 and 89 degrees: There will be various combinations of both Lengthwise and Rotational movement.
A common theme in learning to drive a truck is simply developing new awareness. The main difference between an experienced driver and a beginner is knowing exactly where to focus and when. They have a firmer grasp of some simple fundamental principles.
Kingpin pressure is another crucial awareness. You should strive to constantly be aware of the angle of offset between your tractor and the trailer. In other words, what is the general direction that the tractor is pushing against the kingpin? You can see this in a broader sense as being aware of the front part of the trailer.
I ask myself, “In which direction does my tractor need to push the front part of this trailer (the kingpin) in order to make it rotate around the back tandems and point where I need the back tires to roll?”
Be more mindful of the front part of the trailer. The trailer behaves very much like a wheelbarrow.
Additionally, you need to be more aware of the precise location of your rear trailer tires on the ground. Another big reason new drivers struggle is that they don’t pay attention to the ground. An acceptable path must be determined during your set up and diligently kept in focus. Successful Backing is really about tire position. Tire position is achieved by pointing your trailer towards the precise path. Successfully pointing the trailer involves pushing against the front part of the trailer to make it rotate around the back tandems.
Most new drivers fail to get back in front of the kingpin soon enough. This is where the element of timing comes into play. It will take some practice to learn how long it takes the tractor to get from the side of the kingpin, to the front of the kingpin. Be patient with yourself. That will just take some repetitions and careful observation.
Question: How do I know when I’m at the front of the kingpin if the kingpin is never visible?
Answer: You will see the exact same amount of trailer in BOTH mirrors. Using both mirrors frequently is a must. Don’t let yourself have a favorite mirror. Because, using one mirror more than the other will deceive you.
A good starting plan of action:
Decide on an acceptable path for your trailer tires that will lead to their final resting position on the ground.
Pick out something noticeable on the ground that will serve as a Tire Target along this predetermined path.
Push the front part of the trailer so that the whole trailer rotates around the rear tires and keeps it pointing towards this tire path.
Once the trailer is pointing where it needs to be you must get back to the front of the kingpin quickly to avoid knocking it off course.
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