Vehicles used regularly for the carriage of motor cars over long distances are generally well equipped with specially designed wheel wells/chocks, anchor points, winches and other restraining devices, but operators carrying motor cars intermittently for short distances are tempted to rely on the force of gravity or on inadequate cordage lashed to the suspension members of the motor cars being carried.
Where wheel chocks are used they should be secured to the tray or the special wheel tracks by 10mm pins or bolts capable of being locked to prevent dislodgement by vibration. Chocks should be firmly placed on each side of all vehicle wheels. Some chocks incorporate the securing winches, see below.
Anchor points on the carrier should be fixed securely to the metal members of the chassis and be capable of withstanding a force of at least 2 tonnes acting in any direction through which lashings or restraints may be attached. The number of anchor points on each side of the carrying vehicle should be related to the sum of the total number of axles of motor cars carried at a given time.
It is now general practice to affix tensioning winches to car carrier trucks and trailers wherever the design of the truck or trailer permits. These comprise a winch and high tensile steel chain or 4mm wire rope with a hook at the attachment end of the chain or wire rope. If wire rope is used it is essential that the wire ropes are directed around pulleys.
The more elaborate winches are combined with wheel chocks and are fully adjustable up and down the length of the deck. This system ensures that there is pressure against the wheel and pulls the car down without bending the car body.
The number of winches used per car on the truck or trailer will vary from two, three to four. Should only two winches be affixed they must be capable, together with chocks, etc to restrain the car so that the ‘g’ force criteria outlined in Basic criteria and precautions is met. Ideally, four winches should be supplied.
Basic criteria and precautions
Most car manufacturers provide securing points (holes) in the chassis of their products for the attachment of chain hooks. These also vary from two, three to four sites.
Where securing points are not provided on the car, the chain or wire rope is wrapped around the axles at the front and rear ends of the car. On these occasions care must be taken to ensure that chains and wire ropes do not damage brake hoses or other components.
Restraints must be attached to special underbody brackets, when fitted to the motor car. When special vehicle underbody brackets are not provided, lashing over the axle is acceptable. In this instance, care must be taken to ensure the freely sprung body cannot be damaged against adjacent fittings. Motor car manufacturers recommend that to avoid possible damage to the drive train of motor cars being carried, the parking brake should be firmly applied and manual and automatic gear boxes set at neutral.
Automatic gearboxes should never be set at the ‘low’, ‘second’, ‘drive’, or ‘reverse’ positions.
Front and rear lashing must be used in association with wheel chocks. At least two lashings should restrain each vehicle.
The maximum legal weight limits and vehicle dimensions must not be exceeded. Particular attention should be given to loading height, especially when transporting light vans etc.
Care should be taken to ensure that all loose loading ramps are safely secured. Hydraulic ramps and decks should be secured in the locked position.
Fuel tanks of motor cars being carried should contain only sufficient fuel for the motor car to be driven on and off the car carrier in the storage yards.
Several precautions should be taken to ensure that the vehicle being towed does not break away or become loose and to prevent further damage to the vehicle under tow.
A towing sling and spacer bars should always be used. Safety chains, to take the load off the winch and cable while the vehicle is under tow, are necessary.
Slings should be hooked to the lower suspension arms or, if the rear of the vehicle is lifted (towing it on its front wheels), hooks and chains should be attached to the rear of the axle. Wooden blocks, rubber cushions or fabric fenders should be used at splash pans, tail pipes, oil sumps and fuel tanks, to avoid damage to these components.
Do not hook on to the tie rods, steering linkages or other parts that could be damaged by unusual pressure. Do not hook over the top of an axle or suspension member because the hook could become unfastened during travel.
Make sure that spacer bars are retracted and locked before towing. Check that the car is in neutral gear and the parking brake released before towing.
On rear wheel drive vehicles, the chief advantage is that the vehicle’s transmission will not limit either towing speed or distances. This can be a significant advantage when towing trucks.
Practically all passenger cars with automatic transmissions present limitations during towing. Generally such cars towed on their rear wheels should not exceed a speed of 40km/h and a distance of 20km unless specific factory recommendations allow higher limits. The main disadvantage in front-wheel towing is the danger that would result if the front wheels failed to remain secured in the straight ahead position, allowing the disabled vehicle to swing. Steering wheel locks, specially designed for this purpose, are available in the trade.
