You will have many opinions of how to and not to tie a car down. Here are
my methods and the reasons behind them, most based on actual transport.
Anything from a 1100 Lb Formula Ford to a 25 ft bread truck on a 14ft trailer (
the
wheel base just fit )
Wheel harnesses would be the fastest least messy way. They are used on many
tow truck wheel lifts. ( I've never used wheel harnesses )
2" wide nylon ratchet straps rated for 2000 lb or more each. These are much
better than chains as they have some give rather the tight or not of a chain.
Chains are used in a specific app I'll list later.
If the straps can be run at a 30* to 60* angle, I hook the right rear of the
car to the right rear of the trailer. If the run is too short and / or the
angle too shallow or severe, I hook the right rear of the car to the left rear
of the trailer. ( and the LR to the RR ) This method holds the car from front
to back and from left to right. Each end of the car must use the same method
but different methods can be used on each end of the car.
Now, where on the car to attach. I try to attach to a point that does not
move up and down ( or slightly moves ) as the car bounces up and down. If you
attach to the frame the straps will be loose tight as the car bounces, if you
use a chain it can tear out the attaching points.
The rear axle is a good place to attach because it does not move. For a A
arm front suspension I wrap a short extension around the front leg of the A (
the area where the bushing is ) This area does move up and down slightly but is
the best compromise. Also look out for interference with the tie rods.
Chains are used on factory delivery car trailers but they use the factory
provided tie down points. They also pull the car straight down against the
bump
stops to prevent the loose tight bounce. This method isn't practical on a one
car hauler.
Flat bed tow trucks use chains and a winch with acceptable results but this
isn't practical for a trailer.
You will also need to locate the car front to back. Low tongue weight due to
a miss positioned load is at minimum a difficult drive and at max a way to
spit the truck and trailer off the road. Tongue weight should be in the 10 to
15% of total loaded trailer weight. I've developed a feel when loading a car,
drive on the trailer and the tongue lifts, continue driving until you feel the
trailer tilt over center, this is usually just right.
Slightly high tongue weight is preferable over too little. Another way to
judge is measure the rear truck bumper height with the trailer attached and no
car. Load the car and move it forward until the bumper is lower than before.
Perhaps 1 to 2 inches? It will depend on the truck spring rating.
Harold
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