Tow straps / Recovery straps ( from John Akers Chairman, Safety/Education Committee
Arizona State Association of 4-Wheel Drive Clubs, Inc.
31Jan1994 )
A tow strap is a very useful device made from nylon webbing. It is
stretchable under tension. A tow strap allows one vehicle to assist another
through a difficult spot from a distance of 20 or more feet away. By
connecting the strap between the two vehicles, quite often winching can be
avoided. When attaching the recovery strap to a vehicle, always use the towing
hooks.
Quality winch accessory kits always include a recovery strap. Often, a
stuck vehicle will be freed more easily with a tug than with the winch. Many
strap designs provide a controlled stretch capable of reducing shock loads.
Before unwinding yards of cable, try a pull with the recovery strap.
Tow straps come in various sizes, from 2" wide to 4" wide and lengths of
up to 30 feet. A good high quality strap is preferred.
The recovery strap should be thought of as a large energy storage device.
The strap will convert the kinetic (or speed energy) of the towing vehicle
momentarily into spring potential energy. If all goes well, this energy is
largely converted towards pulling out the stuck vehicle. However, if the
anchor breaks loose, all of this massive energy is converted to high velocity
energy of whatever weight remains attached.
For example, if the towing vehicle weighs 3,000 lbs. and is moving at just
10 mph when the anchor breaks, a 3 lb. shackle will become a cruise missile
flying at over 300 mph. Just as a piece of straw can penetrate through a
telephone pole at this speed during a tornado. So will the cruise missile
strap blast through a vehicle. The message here is: If you're going to use the
recovery strap, know how it works.
It is this concept that makes shackles and anchor brackets a double-edged
sword. We need to make them heavy to be strong, but this virtually demands
very strong mounting. All of us who understand these concepts regarding
recovery straps and anchors should do everything we can to help the novice
off-roaders. Please do your part.
Broken recovery strap: This is not uncommon, especially if the nylon strap
has been dragged over rocks or scraped across a sharp metal bumper edge and
then put under severe stress. The temporary fix is a safe series of knots
tying off damaged areas. For knot savvy, talk to a teamster, Navy recruit or
an Eagle Scout.
When using a clevis with straps, make certain that nylon material rubs
against the inside of the looped end. Otherwise, fraying and damage to the
strap will result.
Towing with chains In a word...don't. Towing with a chain, in most cases, can be dangerous.
Unlike a tow strap, a chain does not stretch. Under the tremendous loads of
towing, something needs to have a little flexibility, hence the tow strap. By
using a chain, there is nothing in the loop that will give a little. What this
means, simply, is the weakest part will break once sufficient stresses are
imposed. This could be the chain, the tow hook, or some other part of the
vehicle. Can you imagine the force behind a chain link being thrown at you by
a force of 8000 pounds? Chains have their place for the off-highway driver,
but not in towing.
Choker chain
A term familiar to woodsmen and loggers, the choker is a high-tensile
strength link chain with hooks at each end. A six- foot long choker chain is
very versatile, acting as a vehicle recovery tool or reinforcement between two
anchor points.
Tow hooks
Well mounted and well placed tow hooks are a necessity for any four
wheeler. There is usually a great possibility that they will get used.
Factory or aftermarket front and rear frame-mounted tow hooks require
high-tensile strength bolts and self-locking aircraft quality nuts. Attaching
points and hardware must meet OE frame requirements. Never mount directly to
the bumper. Hooks are available with spring clips to prevent straps from
slipping off. These are especially useful for one-person operation. Mounted
upward, downward or sideways, tow hook bolts should align in the direction of
pull. Determine mounting location by the frame height, with the safest pull
being a relatively straight line. Avoid welding tow hooks into place, even in
a sound manner. These hooks may need replacement at some time.
Broken tow hooks: This is a rare occurrence, but possible. If a
frame-mounted hook breaks, a new cable attachment point is necessary. Using
the choker chain as a new attachment point, wrap the chain around the frame or
bumper supports, avoiding brake and fuel pipes, hoses and electrical wiring.
(NOTE: Avoid attaching to the bumper, springs, hangers, suspension parts, axle
or steering linkage.)
Preventive maintenance
Inspect all attaching hooks and straps. Make certain clevis pins are free
of moisture, and lubricate them lightly. Dry out your nylon straps before
storing them. Check tow hook and winch mount bolts and nuts for tightness and
signs of fatigue. Inspect closely for bending or possible fatigue cracks on
any parts affected by the winch loads. Pulleys (snatch block) should be
cleaned and lubricated.
Recovery operations
In recovery operations, it is important that rigging be attached to the
vehicle in such a manner as to avoid damage. For example, in recovery of a
disabled 4X4 vehicle, the winch cable should not be attached to the bumper
because the bumper might be damaged. The frame could be pulled out of
alinement if the cable were attached where the effort was applied to a single
frame member.
On 4X4 vehicles, whether the pull is made from the front or rear, the
effort should be applied to the tow hooks. To apply the effort equally to tow
hooks, a sling should be used between the two hooks and the effort applied to
the sling. A chain is the best item to use as a sling.
If mechanical advantage (snatch block) is used, the block will be attached
to the sling and the winch cable reeved through the block. When a sling is
used in this manner the effort exerted on each side of the sling will be
slightly greater than half the effort exerted by the winch. As the angle of
the sling increases (the sling becomes shorter) the load on the sling becomes
greater. To keep the load within safe limits, the angle of the sling should be
kept at less than 30 degrees; the apex of the angle formed by the sling should
be at least 6 feet from the vehicle.
NOTE: The Arizona State Association of 4-Wheel Drive Clubs, Inc., is an association
of rough-terrain vehicle clubs with the following goals: to promote a more
responsible attitude towards the vehicle use of public lands, to prevent
legislation which would impose undue restriction on recreational 4-wheeling, to
institute programs of Conservation, Education and Safety, and to provide social
and recreational activities for its members. The Association assists the state
and national resource management agencies.
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