David Gilchrist — 7 November 2018
Tow Vehicle Capacity know-how

You’ve been conned. At least it may seem reasonable to believe you’ve been conned going by the wagon train of reports of harsh changes in Queensland that would make it unlawful to upgrade your existing tow vehicle to accommodate your shiny new caravan, that’s both bigger and with more bells and whistles and, consequently heavier.

A story appeared in Queensland daily newspaper The Courier-Mail on August 21 which vastly exaggerated the effect of the current Federal Government rules which only apply to towing capacity upgrades made on pre-registered vehicles.

The article said the Queensland State Government would prevent upgrades to 4WD tow vehicles which would allow them to tow larger and heavier caravans than they previously have, by banning upgrades to the Gross Combination Mass (GCM), of the vehicle and van. The GCM is the total weight a vehicle can carry and tow. That is, the maximum combined weight of a loaded vehicle and caravan or trailer.

The piece then went on to suggest owners who bought a new van would have to invest in a whole new tow vehicle at considerable expense, instead of upgrading the towing capacity of existing vehicles with aftermarket products and qualified mechanical work.

Federal laws stipulate that new and unregistered vehicles cannot have their GCM upgraded beyond the level the original manufacturer sets. Vehicles which have already been upgraded are exempt.

Federal laws do, however, allow for a vehicle’s Gross Vehicle Mass (GVM) to be upgraded. The GVM is the maximum weight that a vehicle can carry including its own weight. This is the maximum or total weight of a loaded vehicle (including body, payload, fuel and driver) and it is a figure set by the manufacturer and is lodged with registration authorities and governs all applications and is stamped on the compliance plate of the tow vehicle.
The Queensland Government was reported to have been prepared to take this issue a step further and ban upgrades to already registered towing vehicles, axle capacity increases and GVM upgrades on in-service vehicles which had previously been upgraded by another State.


Exaggerated reporting went well beyond The Courier-Mail, hitting social media and online forums and newsletters such as The Grey Nomads on Line in a flurry of confusion that seems to emphasise a need to be first with the news rather than accurate.

That exaggeration was noted by both the Australian Automotive Aftermarket Association (AAAA), the nation’s peak body for the manufacturers, distributors and retailers of automotive parts and accessories, along with the Caravan Industry Association of Australia (CIAA), the peak national body for the caravanning and camping industry.

Both organisations were concerned that these stories understandably alarmed industry businesses and their customers.

Caravan World magazine spoke to Stuart Lamont, CEO of the Caravan Industry Association of Australia, who warned that those looking into the issue should be cautious. He says that the poor reporting has caused much confusion in the market and that early reportage was “dismissed by the Minister in charge”.

Lamont says the confusion arose around a circular published by the Federal Department concerning GCM upgrades (as opposed to GVM upgrades) which has been driven out of the Australian Motor Vehicle Certification Board surrounding safety for consumers and confusion surrounding obligations by the Original Equipment Manufacturer regarding product which has been modified after-market. 

“This has caused quite a flurry of activity out of commercial operators whose business models are to be interrupted,” he says.

According to Lamont and Stuart Charity, Executive Director of AAAA, both organisations support 4WD owners and caravanners in obtaining responsible vehicle modifications that ensure safer towing.

Charity tells Caravan World that it has always been the case that all Australian drivers could have their vehicle’s suspension modified for a GVM upgrade.

“So that’s basically upgrading the carrying capacity of the vehicle and that’s done pre-registration and the new GVM is noted on the compliance plate of the vehicle,” he says.


However, Stuart believes the poor media reporting wasn’t solely responsible for the confusion. Charity says that earlier in the year, “there were a number of companies that, when doing GVM upgrades, they were also re-rating the GCM or Gross Combined Mass of the vehicles, which is the towing capacity”.

Information from Federal Department of Planning, Transport and Infrastructure confirmed the confusion around GVM and GCM upgrades has a long history.
According to the Department, light vehicle towing capacity is limited to that set by the first stage manufacturer and that second stage manufacturers are not permitted to increase the towing capacity as part of an SSM Identification Plate Approval (IPA) that results in a GVM upgrade.

However, it clarified that that limitation isn’t retrospective, so GCM increases already underway will be allowed, but new ones will not be accepted. In other words, the maximum legal towing capacity of a light vehicle is that set by the manufacturer.

The Federal Government’s advice to the CIAA says Australian States and Territories all have the same law and do not permit increases to the braked towing capacity of light vehicles.
Although the Federal regulation does not allow the towing capacity to be changed, a practice of accepting such changes has come about in South Australia that Federal authorities did not stop.

Now here’s the mischievous bit. The Federal Government informed the CIAA that while manufacturers “have the resources to test their products in a manner that is not likely to be achievable by aftermarket or Second Stage Manufacturers. Some of these manufacturers have claimed to have conducted suitable testing but, despite requests from several government agencies, no test reports have been forthcoming.”

Consequently, the Federal Government believes vehicle braked towing capacity increases are unwise from a technical viewpoint as well as being legally dubious.

That’s why the DPTI will not accept applications for light vehicle braked towing capacity increases from 27 September 2018 although existing approvals and applications made before that date will be honoured.

Departmental advice to the CIAA says certain aftermarket and Second Stage Manufacturers “have claimed to have been working with original manufacturers to develop their products”. Consequently, in those cases the increased braked towing capacity can be considered on the basis that it is a manufacturer-endorsed rating.

AAAA’s Stuart Charity confirmed that there is no restriction on modifying suspension to increase the load carrying capacity of a vehicle, improve the ride or gain extra ground clearance as long as the changes are within the Federal regulations.

Charity said the trouble with rating a GCM upgrade is that there is no agreed testing regime. He said that’s because towing can impact many things including the drive line and chassis.


There are many circumstances in which you might upgrade your GVM. If you are serious about carrying a substantial load when you tackle those extreme outback locations, or you’ve kitted yourself with a significantly bigger van, then upgrading your GVM might be worthwhile.

If your new van purchased also included picking up a new SUV and you still feel included to up the GVM rating, then you need to get it sorted prior to registration. Some aftermarket suspension specialists will install what you need as an approved suspension kit and attach an additional compliance plate advising of the upgraded GVM, and you may also need the supplier to organise a replacement axle ratings sticker. The upshot is your new vehicle with its upgraded GVM will now be legally registered and driven in all States of Australia, providing the kit and supplier has approval from the Federal Department of Infrastructure and Transport.

Kits may include a range of upgrades from steering dampers and control arms to coil springs and shocks. Depending on the sort of work you intend to do, other modifications might impact on brakes or even transmission.

For vehicles that are already registered, an authorised automotive engineer must inspect the tow vehicle and issue it with a compliance certificate which means your upgraded vehicle now meets ADR standards, ie it’s safe to drive.
Remember that once your vehicle is registered it falls under the jurisdiction of the State authority in which it’s registered.

And there’s the rub, with a complex array of possible modifications, the best approach is to always use an expert automotive engineer as State regulations are complex across a vast array of rules and regulations covering areas such as replacement tyres on standard rims, non-standard tyres and rims, replacement tyres and rims on vehicles with modified axles, suspension and steering, shock absorbers sway bars, track rods, strut braces, power steering, steering wheels, Rose and Heim joints and lowering or raising vehicles. There are far too many to cover here.

What’s more, there are no specific vehicle standards or regulations that apply to a vehicle’s suspension. Instead, just short of 30 different standards and regulations impact on the suspension alone. Which only serves to illustrate the whole issue is complex and difficult.
The trick is, always seek an expert who will sort out a kit for you that will do the job without falling foul of State authorities. What’s more, check out further info through State authorities to make sure you’re on the right track with any minor, major or specific modifications.


If you do need to carry a heavier load and don’t upgrade your GVM, then you are driving a vehicle that doesn’t meet safety regulations. This puts your safety and that of those around you at risk, as well as potentially affecting any insurance claim if you do have an accident.In terms of safety, if your vehicle exceeds its maximum GVM it becomes harder to manoeuvre and is inherently less stable.

Upgrade your GVM and you’ll be on the road with a vehicle ready to take on whatever you ask of it within that new GVM limit. This means, for the work you want to do, you’ve improved your vehicle's handling, carrying capacity and ride, together with its towing stability.

Now, if you’re busy tut tutting and scoffing at the need to be mindful of your GVM then keep in mind that a combination of a little too much weight, a bad road and a little too much speed could potentially see you on the side of the road with a bent chassis, waiting for a recovery vehicle and expecting a hefty repair vehicle or, even worse, not being able to have your much-loved tow vehicle repaired at all.


Both the AAAA and CIAA are seeking national uniformity in relation to the highly responsible, effective and road safety enhancing 4WD modification rules which currently apply across the rest of the country, as the recent rule changes highlight legal inconsistencies.

Charity says the AAAA would like to see uniformity in regulations when it comes to minor suspension upgrades or tyre diameter. He added the AAAA is calling for uniformity on 75mm overall suspension lifts that includes a 50mm lift on the suspension and 25mm on tyre diameter.

“It makes no sense to think that vehicles which are highly likely to cross State lines are subject to different modification rules and we do want to see the Queensland Government take into account the 4WD suspension modification rules that apply in all of the other States and Territories,” he says.

The 4WD Industry Council claims as part of 'Operation Lift', Queensland Police fined, issued Defect Notices and impounded modified 4WD vehicles based on recently-changed Queensland laws.

Queensland 4WD laws were changed with no notice and they appear to be retrospective: motorists had no idea that vehicle lift modifications made legally last year may be illegal today. 

Many of these motorists who had responsible lift changes made to their 4WD vehicles were ambushed during this blitz.

As we went to press the QLD Government announced its vehicle lift modification laws will change to be more consistent with other jurisdictions. In October the Government will change sections of the Queensland Code of Practice, which governs vehicle lift rules. The changes will raise the maximum lift certifiable in QLD from 125mm to 150mm. Owners of vehicles with Electronic Stability Control will be able to raise their vehicles up to 75mm (incorporating a max of 50mm suspension and 25mm tyre increase) without certification in QLD, consistent with NSW and VIC.


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