A Comprehensive Guide to A-Frame Towing

One of the most common towing configurations that private drivers undertake is known as A-frame towing. This is when two vehicles are connected with a triangular shaped frame (known as an ‘A-frame’). This configuration can be used to tow cars, caravans, trailers and more.

As practical as A-frame towing is, it’s also a complex undertaking that’s subject to meticulous government regulation to ensure the safety of everyone on the road. As Perth’s resident experts in all things towing-related, we decided to compile a comprehensive and exhausted guide to A-Frame towing.

Here’s everything you need to know about towing with an A-frame – from the relevant laws to insider tips on how to do it successfully.

When Is Towing Allowed in Australia?

According to Australian Road Rules, the driver of a motor vehicle is only allowed to tow another vehicle when certain requirements are met:

  • The driver is able to control the movement of the towed vehicle.
  • If this is not possible, then the vehicle must have operable brakes and steering, with a person sitting in the driver’s seat operating these controls.

Even under these conditions, it must still be deemed safe for the vehicle to be towed. This means that that the vehicle must be in safe, operable condition, that the environment must be deemed safe for towing and that any other variables are accounted for.

If you can satisfy these requirements, then you’ll be allowed to tow a vehicle in most parts of Australia (with a notable exception in NSW). Even so, it’s always a good idea to carry a printed copy of the bulletin outlining these towing requirements. You’ll also want to carry any relevant reports (related to the vehicle), approvals and any other relevant documentation. This goes a long way towards diffusing any potential complications with law enforcement along the way.

Finally, the A-frame device used for towing must also be up to spec. If you’re unsure if yours is, consult a chartered engineer to confirm that your towing device meets the requirements laid out in the aforementioned bulletin. You may also be required to submit an application to the Department of Transport (DoT) if you intend to tow a vehicle using an A-frame.

Here are a few additional regulations to keep in mind:

  • The towing configuration must not exceed 19 m from the front of the towing vehicle to the rear of the vehicle being towed.
  • Dangerous projections must be eliminated. This includes projections from the A-frame as well as from either of the vehicles.
  • Most Australian jurisdictions also require that both vehicles be legally registered at the time of the towing.

Following on from the latter point, towing a vehicle that is out of use and currently unregistered could be against the law, so it’s certainly worth checking with your local Road Transport Authority to verify the prevailing regulations if you intend to tow a vehicle with an expired registration.

Overview of the Legal Requirements for Towing a Vehicle in WA

This is an overview of the prevailing laws governing vehicle towing Perth & WA:

  • Only one vehicle may be towed at a time. There are no exceptions with A-frame towing.
  • If a vehicle is not roadworthy, then it cannot be towed. Both vehicles must meet registration requirements and be deemed safe for road travel.
  • The vehicle being towed must be unmanned; no passengers are permitted inside.
  • When a vehicle is not being towed, the tow bar and coupling may not obscure the lights or registration plates of a towing vehicle.
  • Following distances apply for towing configurations. If your configuration is longer than 7.5 m, then you must stay 200 m ahead or behind any similar vehicle (except when overtaking).
  • Speed limits are different for towing configurations than for regular vehicles; the maximum permitted speed is 100 kph or the posted speed limit – whichever is lower.
  • If the total vehicle configuration weighs more than 4.5 tonnes or is longer than 7.5 metres, you are not permitted to stop for more than an hour in a built-up area unless you are actively loading or unloading goods. In a non-built-up area, you are only permitted to stop on hard shoulders, in truck bays or in zones that are explicitly set aside for this type of vehicle parking.

Equipment for the Towing Vehicle

A vehicle must be properly equipped for towing in order to be legally used for this purpose. This means that the A-frame, couplings and tow bar must all be properly designed and – just as important – properly fitted.

Here are a few equipment-related requirements for your towing configuration:

  • The vehicle doing the towing must be fitted with electrical sockets that enable the use of trailer lights and (when necessary) brake-light connections.
  • The vehicle may need to be strengthened in order to carry out the towing. This could include special considerations for the suspension or transmission systems.
  • Extra cooling of the transmission oil may be required for towing vehicles with an automatic transmission.
  • A load distributing device may be required for the towing vehicle. If so, this will usually be indicated in the manufacturer-issued operator’s manual.

Tow Bar Requirements

The Australian Design Rules, Standards and Regulations list specific requirements for the tow bar:

  • For vehicles manufactured after January of 1992, the tow bar must be clearly marked with its load capacity. It must also indicate the part number issued by the tow bar manufacturer or (at minimum) the type of towing vehicle it was designed for.
  • The tow bar may not protrude in a way that could be deemed dangerous, nor may it have dangerous sharp corners that could pose a threat to other motorists.
  • The tow bar and coupling must be rated to withstand the total mass of the towed vehicle and the A-frame coupling.
  • Attachments for connecting safety chains must be in place on either side of the tow bar coupling.
  • These attachments must be capable of withstanding the indicated load capacity of the tow bar.
  • The safety chains must be mounted in such a way as to maintain the direction of a trailer in the event that the coupling fails or disconnects.
  • The chains must also be capable of supporting the drawbar and keeping it from touching the ground in the event that the coupling fails.

If the tow bar has a removable towing lug, the safety chains should attach to the non-removable portion of the tow bar; barring this, an additional chain must be in place to keep the tow bar from disconnecting in the case of failure of this lug attachment.

Why to Consider Hiring a Chartered Engineer

Many of the regulations that affect A-frame towing are highly technical in nature. We’ve done our best to present them in layman’s terms in this post, but the reality is that nothing short of an expert’s understanding will suffice.

With this in mind, we recommend that you consult with a chartered engineer to confirm that hardware and towing configuration comply with the prevailing regulations (the DoT recommends the same).

Safely towing a vehicle is a complex undertaking, and there is absolutely no room for error. Consulting with a qualified engineering firm works to protect the property you are towing. But more importantly, it safeguards the wellbeing of the operator and other motorists on the road. The stakes are high, and there’s no margin for error.

The following sections outline a few of the design issues that an engineer will check and assess:

The Design of the Coupling

The A-frame coupling is a crucial piece of hardware, and it must conform to a very specific design criteria. In the broadest sense, it must strong enough to couple the two vehicles and hold them together during the towing process.

Australian Design Rule 62 (which addresses mechanical connections between vehicles) actually provides specific criteria in this regard. It outlines the permitted gross vehicle mass (GVM) for a given coupling strength.

These are further government-mandated criteria for A-frame couplings:

  • The coupling has to permit sufficient angular motion between the two vehicles; this assists with shock absorption on rougher terrain.
  • The coupling must be secured to a chassis, member, sub-frame or otherwise substantial body member of the vehicle being towed.
  • The coupling may be connected to the vehicle’s bumper – but only when approved by the manufacturer.
  • The coupling must ensure that no more than two metres of space is maintained between the two vehicles.

In addition to this, the coupling must be marked with the following:

  • Name and trademark of the manufacturer
  • Rated capacity
  • VIN number of the vehicle being towed
  • VIN number of the vehicle doing the towing

The Design of the Safety Chains

It’s also required that the vehicle being towed is secured to the rigging with chains in case a problem with the coupling develops. The size (gage) and number of the chains used depends on the GVM of the vehicle being towed.

As a general rule, two steel chains are required when the vehicle weight exceeds 3,500 kg. These chains must be able to sustain a minimum breaking stress of 800 Mpa. The size of these chains varies depending on the GVM:

  • For vehicles with a GVM of 3,500 to 4,300 kg, chains must be at least 7.1 mm.
  • For vehicles with a GVM of 4,300 to 7,500 kg, chains must be at least 9.6 mm.
Towed Vehicle GVM in kg Nominal material size in mm Applicable Australian Standard
0 to 4300 7.1 AS 2321-1979
Over 4300 & up to 7500 9.5 AS 2321-1979

Calculating the Towing Capacity

You must also take a coefficient called the ‘towing mass ratio’ into account. This is a technical calculation that takes two different values into account:

  • Tare Mass of the Towing Vehicle: Tare mass of the towing vehicle when it is not towing another vehicle
  • Laden Mass of the Towed Vehicle: The mass that the vehicle being towed exerts on the towing vehicle

The tare mass of the towing vehicle is at least 3.5 times higher than the laden mass of the vehicle being towed. This ensures safe handling and safe braking throughout the towing process.

For vehicles with a GVM of or below 4,500 kg, it’s common for manufacturers to specify the towing limit in the user’s manual. When this is the case, these limits must not be exceeded. Ensuring this means checking the rated towing capacity of every component used in the towing process – including the tow bar, the tow ball and the A-frame itself.

35 km/h stopping distance Average deceleration rate Peak deceleration rate
Vehicles with mass under 2.5 tonnes 12.5 m 3.8 m/s2 5.8 m/s2
Vehicles with mass 2.5 tonnes or more 16.5 m 2.8 m/s2 4.4 m/s2

Assessing the Steering Configuration

The steering capability of your towing configuration must also be considered to ensure the coupled vehicles are manageable. Specifically, the two-vehicle combination must be able to execute a turning radius of 12.5 m (as measured from the outside wheel track).

Furthermore, when the vehicle is being towed in a straight-line direction, it must follow in the path of the vehicle doing the towing. Regulations stipulate that it not deviate from this track by more than 100 mm.

Other Towing Considerations to Remember

Safely towing a vehicle has to do with more than the specs of the vehicle doing the doing or the strength and resilience of the coupling that joins the two vehicles. You also need to take the necessary precautions to ensure that other motorists sharing the road with you are able clearly see your movements and interpret your intentions.

Lighting for Your Tow Rig

Lighting is a crucial aspect of your tow rig. The following lights need to be affixed to the rear of the vehicle being towed:

  • Two stop lamps (brake lights) that illuminate in red when the driver engages the brakes
  • Two tail lamps that illuminate continuously in red whist the vehicle engine is engaged
  • Two turn signal lamps that illuminate in amber when the driver engages the turn signal
  • A single registration plate lamp that clearly illuminates the number plate (of the vehicle doing the towing) to the rear of the vehicle being towed

There are different approaches to fixing these lamps to the towing configuration. One is to use the lighting system of the vehicle being towed by connecting it to the other vehicle’s electrics. This allows you to use the brake lights and turning indicators of the vehicle being towed. You may also affix a portable light bar to the rear of the vehicle being towed.

Needless to say, these lighting systems must be fully operable for the duration of the towing operation.

Am I Allowed to Carry a Load in the Vehicle Being Towed?

The short answer is: Yes, carrying a load in a towed vehicle is permitted under Australian regulations. However, it’s important to remember that all of the mass-related stipulations must be assessed based on the final weight of the vehicle (i.e. after the load has been added).

For example, a vehicle that weighs less than 750 kg does not require an additional braking system when being towed. But if a load is added to the vehicle, bringing the total mass over 750 kg, then brakes are required.

Likewise, the towed mass ratio must still be observed. The tare weight of the vehicle doing the towing still needs to be at least 3.5 times greater than the laden weight of the vehicle being towed once the load has been added.

Generally speaking, you always want any additional load to be as low to the ground as possible. This helps to maintain a low centre of gravity and protects against the risk of tipping. A higher-positioned load will adversely affect the handling of the vehicle combination.

Special Signage: ‘Do Not Overtake Turning Vehicle’

If your towing configuration is at least 7.5 metres long, you are required to display a ‘Do Not Overtake Turning Vehicle’ sign on the rear of the configuration. This is an important safety consideration for longer configurations, as other motorists may misgauge how the turn will play out – placing themselves and others at risk in the process.

When this sign is attached to your configuration, other vehicles are required by law to give way whilst you use some portion of an adjacent lane to execute a turn. In other words, this gives you the right of way at potentially dangerous intersections.

The display of this sign is more than an operator’s privilege; it is also the law. Not displaying it in qualifying scenarios could be considered an offence. The same applies to displaying this sign when the towing configuration is not at least 7.5 m long.

Be mindful of these requirements when navigating turns. If even a portion of your towing configuration must use an adjacent lane whilst turning, then the configuration is likely longer than 7.5 m.

Expert Driving Tips for First-Time Towers

It’s important to understand that operating a towing vehicle is much more complex and involved than merely driving a car. For some drivers, the task can be overwhelming and downright tiresome. If you have never driven a tow vehicle, it is well worth considering whether you are up to the task.

For inexperienced operators, it’s important to practise on a safe stretch of road before proceeding into areas with traffic, where complex manoeuvres may be required. Here are a few driving tips to keep in mind:

  • The vehicle you are towing will have a tendency to cut in when turning; anticipate this and allow for the extra length of your towing configuration when navigating corners and curves.
  • Your towing configuration is much heavier than a regular vehicle and has greater momentum when travelling at the same speed. This means that greater distance is required when braking.
  • Taking curves and corners requires a light touch with braking – and all the more so on slick or slippery roads.
  • Never reverse the coupling combination of an A-frame, as this will compromise your directional control.
  • If you have never used a specific vehicle for towing, it should be noted that your vehicle’s performance will be significantly dampened when loaded. Keep this in mind when accelerating, braking, overtaking, steering and otherwise anticipating hazards.
  • Operators must ‘ease into’ road movements, meaning that accelerating, braking and turning should be undertaken on a gradual basis. Strong steering movements are particularly dangerous, as these can result in swaying of the load being towed.
  • If sway does occur, counteract it by maintaining steady speed (or even slight acceleration) until it subsides. Braking makes swaying worse and should only be done to avoid a threat or hazard.
  • Before driving, adjust your mirrors to account for the extended length of your towing configuration.
  • Be courteous to other motorists and mindful of the potential for a caravan of vehicles building up behind you in places where overtaking is difficult or dangerous. Pull over to the shoulder occasionally to allow these vehicles to pass.
  • Always use a low gear when travelling downhill with a trailer. This reduces strain on your brakes and gives you more control as a motorist.

Be mindful of crosswinds, headwinds and tailwinds, all of which will have a greater effect on your towing configuration than they would on a standard car.

Pre-Towing Safety Checklist

Before embarking, take a moment to confirm the safety of your towing configuration. To begin, conduct a normal service check on the towing vehicle. It’s also important to confirm that the vehicle being towed is roadworthy.

In addition, check the following for both vehicles:

  • Suspension
  • Brakes
  • Lights
  • Tyre inflation

You should also confirm that the coupling and safety chains are securely attached. If you are using two safety chains, check to ensure they are crossed to keep the drawbar from touching the ground in case of a coupling failure.

Finally, confirm that the vehicle being towed is not carrying any heavy loads that have not been accounted for in the towing mass ratio or any other calculations.

Maintaining Safety Whilst Towing

Once you are actually on the road, there are a few additional steps you can take to maintain the safety of your towing configuration:

  • Early in the drive, stop to check the configuration to ensure that it’s holding securely. For longer drives, check the configuration during rest stops as well.
  • Watch the safety chains and couplings to ensure they are secure.
  • Be mindful of the possibility of your brakes overheating and guard against it.
  • Monitor tyre pressure over the course of your drive.
  • Keep an eye on the functionality of your lights.
  • Pay extra attention to the condition of your coupling and towing configuration when driving on rough or uneven surfaces (such as gravel roads).

If you’re in any way apprehensive about the safety of your towing configuration or your ability to safely operate it, please don’t hesitate to contact the professionals at Executive Towing Services.