Increased four-wheel drive rollovers prompt experts to speak out about load ratings

By Matt Brogan on 13th September 2022 News, Regulations 4 x 4, Roof Rack, Roof-top Tent, Safety

SINCE the beginning of the COVID-19 pandemic there has been an alarming increase in roll-over accidents, predominantly because of overloaded roof racks, rooftop platform systems and roof-mounted tents, with first responders and recovery operators reporting that more have occurred over the past two years than at any time in the past.

Forced by travel restrictions to holiday at home, an increasing number of people have taken to Australian roads and trails in search of adventure – but many have done so without fully appreciating the consequences of an overloaded vehicle, a poorly set-up trailer or a combination of the pair.

Many first responders, those involved in off-road recovery and industry experts interviewed by GoAuto have noticed a dramatic increase in roll-over incidents and warn that people are simply overloading their vehicles – particularly when carrying items on the roof.

Several voiced concerns that people are ignoring or unaware of manufacturer advice on safe payload limits; limits that often fall well short of the amount an aftermarket product may advertise as being able to support.

In addition to the increased frequency of roll-over accidents – once rare midweek call-outs now becoming the norm while the weekend peak time for mishaps has become busier – the number of severe incidents has also become a significant cause for concern.

Not only is it dangerous to exceed a vehicle’s payload limit, but it is also illegal. Being found driving an overloaded vehicle can impact a vehicle’s registration and warranty status, insurance coverage, and even result in a fine and loss of demerit points depending on the state or territory in which the transgression takes place.

GoAuto has spoken with several sources experienced in the field, including Dave Gridley, the owner and manager of Admiral Towing in Gippsland, about the ever-increasing number of four-wheel drive rollover accidents.

Mr Gridley, who specialises in the recovery of vehicles from the remote Victorian High Country (VHC), said a lack of knowledge, especially among novice four-wheel drivers, was behind the uptick in rollover accidents, and that understanding the manufacturer’s recommendations on rooftop loading is the key to staying safe.

“Rollover accidents are definitely happening more, and I believe a lot of that comes down to people carrying too much weight. It’s very easy to get to a point where the roof is overloaded,” he said.

“People are taking a lot more equipment with them, in and on their four-wheel drive, now, but they need to keep in mind that there is only so much stuff you can take, and that this equipment must be included as part of the overall weight you’re carrying.

“In a lot of our more recent recoveries we’ve found vehicles are overloaded, and that there is a lot more equipment on the roof than there really should be. With extra weight on the roof, it doesn’t take a lot to make a four-wheel drive roll over.”

Mr Gridley urged four-wheel drivers to understand the rooftop payload capacity of their vehicle, to drive according to the conditions, and to remember that anything carried on the roof must be included within the vehicle’s overall payload capacity.

“My advice is to limit what you take – and to stick to what you need. Trying to reduce the amount of weight you’re carrying, especially on the roof, is the best thing you can do,” he said.

“Think about where you’re going and what you need, set your vehicle up correctly, and if you need to, seek the guidance of an expert.”

Emergency service and first responders in the region added to Mr Gridley’s voice, saying it is imperative that recreational four-wheel drivers are particularly cognisant of the dangers associated with rooftop overloading.

Erica and District Fire Brigade captain Russell Wright told GoAuto that although many of the less serious rollover accidents in the VHC go unreported to emergency services, those that require official attendance are often ‘catastrophic’ in nature.

“An overweight vehicle can not only affect the vehicle’s performance, but it may also contribute to how the vehicle handles, particularly in the off-road environment,” explained Mr Wright.

“A top-heavy vehicle is inherently unstable. The higher centre of gravity means it will sway and tilt beyond the manufacturers design parameters making it far more susceptible to a rollover type accident.

“Unfortunately, these kinds of accidents often have catastrophic consequences for the occupants of the vehicle, and in recent times, there has barely been a weekend go by where we’re not called out to an event where someone is trapped, injured, or worse.”

It is important to understand that the weight of the roof rack or roof-top tent – as well as anything carried within – must be included within a vehicle’s overall payload capacity.

For example, if the vehicle has a payload capacity of 600kg and it is carrying 100kg on the roof, then it must only carry a further 500kg inside the vehicle – which includes passengers and fuel, as well as any fitted accessories such as bull bars, water tanks, drawer systems and so on.

As well as impacting the dynamic performance of a vehicle, the heavily-laden roof can contribute greatly to the risk of a rollover accident. Further, suspension lift kits and long-travel suspension may exacerbate the issue.

Raising the centre of gravity can easily unsettle a vehicle that may already be nearing its rollover threshold and will also impact the way a vehicle responds to emergency inputs, such as swerving or heavy braking.

Knowing how much a vehicle can safely carry is often as easy as consulting the owner’s manual.

Many popular four-wheel drive vehicles currently available have a dynamic rooftop payload figure of between 80 and 100kg, meaning that this is the total weight they may carry on the roof while in motion.

For vehicles fitted with sunroof or panoramic roofs, this number may be even lower.

The dynamic weight factors in forces acting on the roof rack or rooftop camper including aerodynamic pressure, body flex and g-forces (from accelerating, braking and cornering) and how these impact the structure of the vehicle’s roof or the handling properties of the vehicle.

As a rule, the dynamic payload figure can be trebled once parked. The static payload figure of most popular models comes in at around 300kg, or sufficient for two adults and a rooftop tent (based on a rooftop tent weight of 80kg).

Some manufacturers will even list a specific rooftop payload figure for use off-road. Again, it pays to check the vehicle’s owner’s manual.

It is worth noting that trade, recreational four-wheel drive and touring set-ups may require an aftermarket ‘backbone’ or chassis to be installed to handle greater rooftop loads.

Reputable four-wheel drive and trade accessories outlets will be able to assist in finding a solution that not only keeps the vehicle legal, but also keeps everyone safe.

*Based on 2022 model year specifications. GoAuto is awaiting confirmation of figures for some makes and models.

^Subaru Outback Sport variants offer 100kg dynamic and 318kg static payload capacity. Subaru genuine accessory cross bars are rated to support 300kg.

To assist, roof rack suppliers such as ARB and Rhino-Rack offer a Load Rating Calculator on their websites.

These tools are designed to prevent inadvertent overloading, which as well as helping to maintain safety and legality – potentially avoiding the risk of voiding warranty and/or insurance coverage.

“There are a number of things to consider when working out your vehicle’s load rating,” explained Rhino-Rack in a statement.

“Firstly, different vehicles have different roof ratings (and) you need to know the load rating of your vehicle. This information will be easy to find in your vehicle’s owner’s manual.

“Secondly, there are a few different load ratings you need to understand. There are on-road and static ratings for all vehicles, as well as off-road ratings for vehicles that can travel off-road.

“Lastly, it is important to remember, if you buy an accessory or holder and attach it to your rack or tray, you must also include the weight of these in your cargo allowance (payload).

“It is very unsafe to overload your vehicle. The ‘she’ll be right’ approach is not appropriate in this context, and failure to follow load ratings in each circumstance could result in damage to your vehicle, potential loss of your load, voiding warranty or insurance, or cause traffic accidents.

“It is illegal to overload your vehicle,” emphasised Rhino-Rack.

Err on the side of caution

The experts agree that when it comes to loading the roof of your vehicle with any accessory at all that it is best to err on the side of caution.

GoAuto spoke with ARB fabricated products manager, Mark de Prinse, who said four-wheel drive owners should take the time to understand the safety aspects behind loading items on the roof of their vehicle, and to check with a reputable reseller if any doubt remains.

“The most important thing we urge our customers to understand is that it doesn’t matter what the rack can hold, it matters what the vehicle roof loading capacity is, the roof limit is the limit,” said Mr de Prinse.

“It’s also very important to remember to include the weight of the roof rack or platform and any accessories in your calculations.

“We’d encourage customers to take the opportunity to chat with our experts and fully understand what product suits their needs, and to get a bit of an education around loading vehicles in general.

“We recommend placing lighter items on the roof and to use a lighter rack where possible to keep your centre of gravity low.

“Make sure you have an adequate tie-down strategy because there’s a safety element that must be considered. You must always make sure the load is evenly distributed and adequately secured,” he cautioned.

Mr de Prinse’s comments were largely echoed by the managing director of the Australian Automotive Aftermarket Association’s Auto Innovation Centre, Luke Truskinger, who said that ultimately it is the vehicle’s roof top loading rating that is the only one that matters.

“The vehicle roof loading capacity is not just about the durability and robustness of the vehicle structure; it also provides a guideline as to the vehicle’s dynamic performance,” explained Mr Truskinger.

“There is no dynamic stability requirement for vehicles sold in Australia, they simply need to pass the electronic stability control test, which is conducted as an unladen test. That’s just one of the reasons it is so important to stay within the manufacturer’s recommendations.

“If you consider that loading a vehicle in this way (with heavy items on the roof) creates a poor dynamic scenario – and that many owners are driving vehicles heavily loaded and across terrain that they may not be used to – then you’re looking at a worst-case scenario.

“I would urge people to understand the difference between dynamic and static loading, to select a reputable product, and to have the product installed by someone who understands these safety requirements.

“There are a lot of pieces to this puzzle, and as an owner, it’s ultimately you who will accept the responsibility for any modification you make on your car – including the way you load it.”

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