Towing Best Practices Module 3

Automotive Towing
Best Practices
Module Three

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Wheel lifts are composed of:

• An under-lift;

• Crossbar (tube);

Module Three: Light-Duty Wrecker Loading and Unloading

Loading and Unloading a Disabled Vehicle With a Wheel Lift

• L-arms (or forks); and,

• Wheel straps.

Wheel lifts are used to tow vehicles by their wheels, hence the name “wheel lift”.

Loading and Unloading a Disabled Vehicle With a Wheel Lift

The use of light-duty wheel lifts should be limited to towing light-duty trucks and cars.

They typically do not have enough lifting capacity to tow larger trucks, buses, motorhomes, large vans, or equipment.

You should always refer to your vehicle’s equipment ratings along with the vehicle’s GVWR and GAWR before you use them to tow anything.

Wheel lift ratings are marked on the wheel lift. There are two ratings: one is a lift rating and the other is a tow rating.

Module Three: Light-Duty Wrecker Loading and Unloading

Loading and Unloading a Disabled Vehicle With a Wheel Lift

Lift Ratings:

If there are two lift ratings specified, one is for the under-lift (boom) in an extended position and the other is for the under-lift in a retracted position.

The greater number will apply to the under-lift in a retracted position and the smaller number will apply to the under-lift in an extended position.

If only one lift rating is specified, it applies to the under-lift at any extension.

Module Three: Light-Duty Wrecker Loading and Unloading

Loading and Unloading a Disabled Vehicle With a Wheel Lift

Lift Ratings

You can calculate the lift capacity of the under-lift at any point on its extension using the following formula:

(E-R)/D (Extension minus Retraction divided by Distance)

Where,

• E = the lift capacity of the under-lift at its most extended point;

• R = the lift capacity of the under-lift at its most retracted position; and,

• D = the distance of travel of the under-lift from its retraction to full extension in some given increment (eg. inches).

Example:

Module Three: Light-Duty Wrecker Loading and Unloading

Loading and Unloading a Disabled Vehicle With a Wheel Lift

Lift Ratings

An under-lift with a lift capacity of 2,200lb in its fully extended position and a lift capacity of 3,500lb in its fully retracted position, and the full distance for the under-lift to travel from full retraction to full extension is 30 inches.

3,500 – 2,200 = 1,300 divided by 30 = 43.3

Thus, the wheel lift decreases (or increases) its lift capacity 43.3lb for every inch the boom retracts (or extends).

In addition to the tow rating of the wheel lift, you need to be aware of the GVWR and the GAWR of the tow truck chassis.

Module Three: Light-Duty Wrecker Loading and Unloading

Loading and Unloading a Disabled Vehicle With a Wheel Lift

Tow Rating

You must never exceed the tow capacity of either the wheel lift or the chassis.

Even though a one-time overload may not produce an immediate failure, it can compromise the integrity of the equipment and cause it to weaken, which can produce a failure later even at a reduced load.

In general, you should never reduce the weight of the front axle by more than half its actual weight capacity.

Calculating a Load For Safe Driving:

Module Three: Light-Duty Wrecker Loading and Unloading

Loading and Unloading a Disabled Vehicle With a Wheel Lift

Tow Rating

Do not tow any vehicle that reduces the weight of the front axle of your tow truck to less than one-half of its unloaded weight.

• ML = maximum lifted load for safe steering.

You can calculate the maximum load for safe steering as shown below:

ML = ½ FAW x WB / OH

• FAW = the unloaded weight at the front axle.

• WB = wheelbase (distance between the center of the front axle and the center of the rear axle).

• OH = overhang (distance from the center of the rear axle to the lift point of the towing device).

Overhang

Maximum Load

Wheelbase

FAW

Front Axle Weight

Module Three: Light-Duty Wrecker Loading and Unloading

Loading and Unloading a Disabled Vehicle With a Wheel Lift

Tow Rating

To use this formula:

Module Three: Light-Duty Wrecker Loading and Unloading

Loading and Unloading a Disabled Vehicle With a Wheel Lift

Tow Rating

a. Divide the unloaded weight at the front axle by two.

b. Multiply the result by the wheelbase.

c. Divide that result by the overhang.

d. The number you come up with is the maximum lifted load for safe steering.

Chassis ratings are typically located on the driver’s door, inside the doorframe, or check the owner’s manual.

For safe steering, do not transfer more than 50% of the front axle weight to the rear axle.

Module Three: Light-Duty Wrecker Loading and Unloading

Loading and Unloading a Disabled Vehicle With a Wheel Lift

Tow Rating

Module Three: Light-Duty Wrecker Loading and Unloading

General procedures when loading an undamaged vehicle with a wheel lift

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Module Three: Light-Duty Wrecker Loading and Unloading

Towing With a Light-Duty Wrecker Using a Conventional Tow Sling:

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Module Three: Light-Duty Wrecker Loading and Unloading

Dollies:

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Damaged wheels, flat tires, damaged suspension, or a locked car can all be conditions that can cause a vehicle to not track properly. You should typically tow a vehicle from the damaged-end leaving the undamaged end on the ground.

Module Three: Light-Duty Wrecker Loading and Unloading

No matter what type of dolly you use, safety is your primary consideration. Always use a dolly when the condition of a vehicle is such that it will not track properly when being towed, otherwise the vehicle could swing into the oncoming lane and cause a serious accident.

Dollies:

See ARA OHS Responsibilities and Industry Supported Safe Work Practices for the Towing and Recovery Industry, Traffic Risk Assessment, pages 26, 27.

Module Three: Light-Duty Wrecker Loading and Unloading

Always consider the extra width of the dolly when towing the vehicle or when installing the dolly. Be extra careful when applying a dolly in traffic. Consider moving the vehicle to a safer location, or apply traffic cones.

Dollies:

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Failure to keep your hands and feet clear of moving parts could result in injury, and watch for pinch points or adjustment holes. Careless operation of the lifting bar could also result in injury.

Module Three: Light-Duty Wrecker Loading and Unloading

Personal safety is also a factor you need to consider when using dollies. Failure to lift properly can lead to back injury, or other strains.

Dollies:

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See ARA OHS Responsibilities and Industry Supported Safe Work Practices for the Towing and Recovery Industry, Traffic Risk Assessment, pages 25, 26.

You cannot tow a vehicle on its drive wheels simply by putting the car in neutral as this can overheat the transmission. This applies to manual or automatic transmissions.

Module Three: Light-Duty Wrecker Loading and Unloading

Since a vehicle cannot be towed on its drive wheels or towed on wheels that are locked by the parking brake, locked cars or cars that you cannot gain access to should be transported with dollies.

Dollies:

General Safety Precautions When Using Dollies:

See ARA OHS Responsibilities and Industry Supported Safe Work Practices for the Towing and Recovery Industry, Booms and Other Towing Equipment, page 55.

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Automotive Towing
Best Practices
Module Three

Thank you. This concludes Module Three

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