trailer, carrying Del Carpenter’s nearly completed 1929 Ford AA-truck
home from its very first showing, was starting to fishtail. Accelerating
onto the Interstate, Del felt the tell-tail sway tugging his pickup back
and forth. "No problem," he thought as he reached for the
tow-vehicle electric-brake control-arm on the steering column. A couple of
taps on the lever will straighten out the tow-vehicle and make it settle
down behind the pickup.
Del instinctively reached for the handle – it wasn’t
there – it was a new braking system that required him to push a button
in. No time to look or feel for the button, the fishtailing trailer was
rapidly getting out of hand and required both hands on the steering wheel.
His late model heavy duty GMC pickup was now being violently jerked back
and forth. Del could see, in his peripheral vision, his white tow-trailer
appearing first in one mirror and then the other. This was truly a case of
the tail wagging the dog!
As fast as Del could turn the steering wheel to counter
the fishtail, the trailer snapped around to the other side. Del’s mind
was racing, "What on earth could have happened that would cause this?
Did I forget to hook up the hitch properly?" he wondered. "Or
did something break?"
There wasn’t much time for contemplation. He was
doing everything he could to keep from losing control. "How much more
can this rig take?" he wondered "If I don’t get it under
control, the trailer will flip, rip loose from the pickup and totally
destroy my 2-year labor of love," he thought to himself.
The Ford AA-truck wasn’t just a ‘restoration project’ to Del. It was
the same type of truck he had first learned to drive. He tells the story
that when he was 6-years old, on his dad’s farm near Ellsworth,
Michigan, he was given the job of steering the truck through the potato
fields. He stood on the seat, the vehicle was put into first gear and the
hand throttle engaged to the point where the workers could walk along side
and throw sacks of potatoes onto the bed of the truck. Del couldn’t
reach the pedals but he took his job of steering quite seriously. That old
truck served them well on the farm and Del grew to love it and the memory
of it. His nostalgic memories and two years of hard labor re-creating it
from a pile of junk were now within mere seconds of being dashed to pieces
on the cold gray concrete of the Interstate.
The trailer was now whipping back and forth so
viciously that Del no longer needed to look in the mirrors to see it. He
could actually see it out of the side windows. He could see the trailer
raise up on two wheels and smoke the tires as they screamed at sliding
sideways on the concrete. The situation was now totally out of control.
His biggest fear was that the trailer would come all the way around and
give the pickup a sideswiping slap. There was no point in babying this
situation any longer as he bore down harder on the brakes. It was
imperative that he get the rig stopped as soon as possible. He wondered if
the tie-downs would continue to hold the AA-truck down or would he see it
burst out of the side of the trailer and seek it’s own destiny. In one
final pendulum like swing, the trailer swung itself entirely around,
dragging the rear end of the pickup with it.
And then it was over. The smell of rubber filled Del’s
nostrils and for a moment, the only thing he could hear was the sound of
blood pumping through his head. As he lifted his eyes, he took stock of
the situation – the truck was still upright, the trailer was still
upright and his AA-truck hadn’t spilled from it. He then remembered that
he was in the middle of the normally busy Interstate. He looked up to see
three lanes of traffic backed up, impatiently parked and waiting for him
to collect himself. The driver of the car in the center lane, realizing
that Del was probably in a state of stock, motioned to him that he should
turn his rig around and pull off on the shoulder. Del deliberately
complied, parked and exited his vehicle. As fresh air filled his lungs and
the adrenaline rush began to subside, he walked around the rig, assessing
WHAT WENT WRONG?
The "what went wrong" didn’t take Del too
long to figure out. Apparently a AA-truck has more weight in the bed, over
the rear dual wheels, than over the front. The heavy metal frame, full
2" oak wood bed and stake rack far outweighed the engine and
front-end components. When Del drove his AA-truck into the trailer, he had
centered it over the axles. Because the trailer was hooked up to the
pickup, he didn’t detect that there was no weight on the hitch. The
absence of weight on the hitch allowed the trailer to think it was in
control instead of dutifully following behind the tow vehicle. Augmented
by the inherent flex of the trailer and tow-vehicle tires, the sway
quickly amplified itself until it became unmanageable.
To remedy the situation, Del loosened the tie-down
straps and moved the AA-truck forward, until there was a noticeable amount
of weight (about 10%) on the hitch. This would prevent the trailer from
trying to lead the tow and keep it behind the pickup where it belonged.
The AA-truck had moved around in the trailer and had to
be re-centered. Remarkably, there was no damage to it. It is amazing that
the AA-truck it didn’t rip free from the tie-downs and smash through the
sides of the trailer.
The trailer, however, had brushed up against the
guardrail and three faint but distinct grooves in the aluminum skin could
The weight equalizing bars on the hitch suffered some
twisting but could easily be repaired.
Del’s nerves and pride, however, suffered the most
damage. Del had had his "stress-test" and his heart was still
beating -- he felt good about that. But, what he didn’t feel good about
was how badly he had underestimated the importance of weight distribution.
Everything was top-notch: the pickup, the trailer, the hitch, the tires,
the tie-downs – and yet, with all his years of experience and knowledge,
like an amateur on his first time out, he lost it.
As he gazed at the black skid marks on the Interstate
concrete that he had just left there, he thought of how close he had come
to having an accident. His rig was new and was set-up ‘by the book’
– everything was the way it should be – with the exception of
weight-distribution in the trailer. That won’t be a mistake he is likely
to make again.
– A tow vehicle should have LT tires for towing. P tires have softer
sidewalls, which can contribute significantly to sway.
- Tire Pressure
– Proper tire pressure for both the tow vehicle and the trailer are
crucial. Under-inflated tires contribute to flex, which can contribute to
- Tongue Position
-- Lower the hitch to tow in a tongue down position. Install a drop-hitch
- Weight Distribution
-- Check for proper weight distribution. A good rule of thumb, is about
10% of total trailer weight should be on the tongue.
- Weight Distributing Bars
– This device distributes the tongue weight evenly across the tow
vehicle and prevents rear-end sag.
- Sway Bar
– This device provides increased resistance to trailer swaying but
please note, a sway bar may mask a problem but not cure it.