Currently set to Index
Currently set to Follow
≡ Menu

Towing capacity; a simple guide to keep you legal

Every day there are arguments, questions and lengthy discussions about what is legal when it comes to towing with a 4WD, and every guide I’ve ever read has not made things overly simple or clear. There is a lot more to towing capacity than just the one rating, and lots of people don’t understand this.

There was an educational exercise done in the Eastern States some time ago, where a heap of vehicles towing caravans and other trailers were weighed in various ways by the transport authority and police.

Majority of them were not legal. Only one fine was handed out with the intention of it being an educational exercise, but it proves the fact that people don’t understand what needs to be done to be compliant. 

So, they jump online, and are met with a barrage of acronyms like GTM, ATM, GVM, GCM, TBM etc etc and soon get lost. Even those who have put a lot of effort into trying to understand it all still get confused; there’s a lot of poorly written (and sometimes wrong) information out there.

Towing with a Pajero

Our simple towing guide is easy to follow and understand

I’m going to make it really simple. You need to meet 7 things in order to be legal

For the purposes of making this article relevant to you, head over to Redbook, select your vehicle and write down the figures referred to in the below points. Alternatively, use your owners manual to find the information or give your vehicle manufacturer a call with your VIN number handy. This gives you a starting point for your towing capacities.

There are 32 ways to make your 4WD illegal, and being over weight in any of the 7 below categories is enough to put you in dangerous territory.

Be under the maximum total weight (vehicle and trailer together)

When your 4WD is attached to your trailer, the total weight of your setup moving down the road must not exceed the Gross Combination Mass (GCM). Every vehicle has a GCM, which you can find in your owners manual, Redbook or by ringing the vehicle manufacturer.

As an example, our Isuzu Dmax has a GCM of 5950kg. As long as our trailer and vehicle do not weigh more than 5950kg we’ve passed the first test.

It’s simply the total weight of your trailer unhitched, and the total weight of your vehicle unhitched, added together.

Your tow ball weight is not considered in the GCM; its a separate concept and anyone who tells you otherwise is full of it.

Tow vehicle weight

What does your trailer and vehicle weigh together?

Be under the vehicles maximum weight

Your vehicle has a maximum weight, which is called the Gross Vehicle Mass (GVM). This is the maximum weight of your vehicle with everything in/on it and includes the tow ball weight.

If we take a 200 series Land Cruiser, you’ll see they have a GVM of 3350kg. The empty vehicle weighs 2740kg, which leaves you with 610kg of weight that can be added. Your payload includes everything that weighs the vehicle down; passengers, drawer systems, bull bars, water, food and the weight your trailer applies on the tow ball.

This is the primary way in which people are overloaded. Normal 4WD’s don’t have the greatest payloads to begin with, and when you add a heap of accessories and gear on board along with a trailers tow ball weight, you’ll go over the GVM very quickly!

Add 2 passengers, a bull bar, winch,  tow bar, fridge and 250kg of tow ball weight (10% of a 2.5 tonne trailer) and a 600kg payload is pretty much gone already.

It is possible to get a GVM upgrade; if you want to know more, have a read of this – GVM Upgrade through ARB. Just know that GVM upgrades should be done with caution. You should always start with the right vehicle in mind; if you have to modify a 4WD so much to make it do what you want it to, then you will end up with other problems that are just as frustrating. Read more here; GVM Upgrades; how much is too much?

ARB GVM Upgrade Dmax

What does your 4WD weigh individually?

Be under the vehicles rated axle capacities

Balancing the load on your 4WD is extremely important. If your vehicle has a payload of 800kg, its assumed that the load is evenly balanced throughout the vehicle. If you put 800kg over the rear axles (or even behind!) you will exceed the maximum weight that your vehicle is rated to carry on the rear axle.

Every vehicle has a maximum weight rating for the front and rear axles. Don’t make the mistake of loading up the rear of your vehicle excessively as you risk chassis damage, insurance companies walking away from claims and a very unstable/unsafe vehicle to drive.

This is especially important for those of you who own dual cab utes. Due to the design, a huge amount of the weight you add ends up over the rear axles, and tow ball weights apply a lot more force than just their weight to the rear axle. Have a read of this – Is your dual cab’s chassis likely to bend?

Rear axle weight

Do you know what your individual axle weights are?

Be under the vehicles rated towing capacity

Every vehicle comes with a maximum towing capacity. If its 3000kg, you cannot tow a trailer that weighs more than 3000kg. Simple. Point to mention; you can tow a trailer that is rated heavier than the the tow capacity, so long as you don’t load it up beyond your tow capacity.

Another thing I will mention is to make sure that the tow bar and tow tongue is also rated to the same (or higher) rating and is suited and attached correctly as per the vehicle manufacturers recommendations. If they have a lower towing capacity than that of your vehicle, that is your limit. Towing capacities are generally not able to be fully used under normal circumstances, due to other limitations. For example, just because you have a 3500kg towing capacity doesn’t mean you can actually legally tow 3500kg, depending on the rest of the setup.

Be under the vehicles rated maximum tow ball weight

Your vehicle will also come with a maximum tow ball weight. This can vary based on the model of the vehicle and the tow bar that you are using, but you cannot exceed the maximum tow ball weight. This is a very important number when considering safe towing as it ultimately determines how stable and safe your tow setup is. If you want to know more, read What is Tow Ball Weight, and why does it matter?

In Australia, the guide or general rule of thumb is to have 6 – 10% of the trailers loaded mass on the tow ball; if you have a 3000kg trailer you should have 180 – 300kg on the tow ball. However, make sure your vehicle is rated to take 300kg of down force on the tow ball.

The Mitsubishi Pajero for example, is only rated for 180kg on the tow ball (up to 310kg depending on what model you have; look it up!). Many trailers have obscenely heavy tow ball weights, especially forward and rear fold camper trailers. This is one of the most important ratings, and you can find out more here; What is tow ball weight, and why does it matter?

It’s important that you consider the direction of your hitch as well, as this hugely changes the tow ball weight and your stability. For more information, check out can you flip your tow hitch?

Tow hitch ratings

Our Isuzu Dmax tow hitch data sticker

Be under the trailers maximum weight

Just like your vehicle, your trailer can only weigh a certain amount when fully loaded. The Aggregate Trailer Mass (ATM) is the maximum amount your trailer can weigh when not hooked up to your 4WD. This, and other figures can be found on the nameplate, usually on the draw bar of your trailer.

Remove the weight of the empty trailer and you have the amount of weight you can add. For example, our Soft Floor Camper Trailer has an empty weight of 540kg and an ATM of 1200kg, giving it a ‘payload’ of 660kg.

However, don’t just go off the nameplate on your trailer, as there’s a pretty high chance it won’t be accurate. Some nameplates can be out by a huge amount when the trailer is empty, and people get caught out all the time. This happens because manufacturers aren’t always honest, and because of different accessories fitted to each trailer.

A lot of big caravans have terrible payloads too (like 2.5 tonne empty, and 2.9 tonne full) giving you a measly 400kg payload for such a big trailer. Add a bit of dishonesty in and you can be in trouble really quickly. You can get caravans, camper trailers and hybrids with good capacities. Our new Reconn R2 has nearly 1000kg of payload!

Nameplate weights for a camper trailer

Have you ever looked at your trailers name plate?

Have the right brakes

Every trailer that weighs over 750kg should have brakes fitted. Some are mechanical and operate with the trailer hitch moving in and out. Some are hydraulic, and most camper trailers and caravans these days are electric.

If the brakes are electric, you need a tow unit in your vehicle, like the Redarc Towpro. You cannot legally tow a trailer over 750kg with electric brakes if you do not have a working module installed in your 4WD.

Dmax tow controller

A Redarc Tow Pro Elite in our Dmax

Go and visit a weighbridge

If you don’t know what your setup weighs, head to the local weighbridge and check it out. Be prepared for a shock; I guarantee you’ll be surprised at the result.

These things have a way of being made more complex than they really are. Take your time to understand them, see a weighbridge and you’ll sleep tight knowing you aren’t going to have issues with the law and insurance.

Why does any of this matter?

If you’ve gotten to the bottom of this post, and you still have no idea why its important to be aware of these things, I’ll make it short and sweet.

Firstly, its a legal requirement to meet the above criteria. If you don’t meet it, you are breaking the law. Beyond that, if your insurance company deems an accident you have was contributed to by being over weight, they can legally walk away or reduce your claim. Not good.

In fact, seriously not good. Rear end a nice Ferrari or sports car and you could be in a world of financial pain for the rest of your life.

Lastly, ratings are given from an engineering perspective as that is what they are designed to do, and if you push beyond that limit the chances of something going drastically wrong increase substantially.

Legal towing setup

There’s lots of risk driving a setup that is not legal

What if you are over weight?

If you do visit a weighbridge, and find out that you have broken one of the 7 things above, there’s a few things that you can do. The first, and most obvious is to ditch as much weight as possible. This may be from your trailer, or from your 4WD.

Start with emptying your setup, and re-packing the things that you really need. Remember that a huge amount of weight usually comes from accessories – second tyres, rear bars, bull bars, winches, extra fuel tanks etc all add up, very fast.

If your tow ball weight is excessive, shifting weight around can help dramatically, just do it sensibly.

If you are still over weight, and there is nothing you can do about it, you can look at getting an engineering certificate to carry more weight. This applies to trailers (see your trailer manufacturer first) and 4WD’s. A number of shops sell off the shelf kits for vehicle GVM (and sometimes GCM) upgrades.

Independent engineers can certify a myriad of different things too, and are worth consulting.

We found our Dmax was going to be over weight at the end of the build, and approached ARB who fitted an Old man emu GVM upgrade.

If you want to know more about what it weighs, check this out – Dmax weight summary

Do you know what you weigh, and that you are legal?

Sharing is caring!

30 comments… add one
  • Ricky Jorgenson March 20, 2019, 4:42 AM

    Great read thank you. I believe I am on top of the weights issue but one question please.
    Prado max tow ball weight of 250kg (plate on tow bar) ATM of trailer is 2371kg with max tow ball weight of 171 kg ( both on plate in van) Can I go to 200 kg ball weight as Long as all other weights are under ie ATM, GVM of Prado and GCM

    Thanks in advance

  • Aaron Schubert March 20, 2019, 10:18 AM

    Hey Ricky,

    You are welcome mate. I think you will find the tow ball weight of 171kg on the nameplate is actually the unladen weight. As in, this is what the tow ball down force is going to be on your vehicle before any gear is added. It shouldn’t be a maximum. The general rule of thumb is somewhere between 6 and 10% for tow ball weight, and generally the tow ball weight will increase as you load it from when it rolls off the factory floor.

    If your trailer manufacturer is still around give them a call and ask.

    Aaron

  • Helen July 27, 2019, 8:05 AM

    Thanks for the info, very helpful. Just 1 thing as I have a Pajero & have crunched all the numbers. The ball weight is a little tricky, if your ball weight is 18o kg or less you can tow up to 3000 kg but if your ball weight is 181 to 250 kg you can only tow up to 2500 kg. Hope that helps someone.

  • Aaron Schubert July 27, 2019, 9:11 AM

    Hey Helen,

    Yep – there’s all sorts of weird and wonderful additions that some manufacturers put in place. Good to hear you understand it all

    Safe travels
    Aaron

  • Bernie August 6, 2019, 8:11 PM

    Great read , in particular re gcm . I have a MUX 2750 gvm , van 3000 with gcm 5750 leaving me on maximum however if I was to get gvm upgrade on MUX to 3200 I should be sweet allowing for 300 rated tow . Can’t thank you enough for simplifying the process

  • Aaron Schubert August 7, 2019, 6:32 PM

    Hey Bernie,

    You are most welcome mate. Just check the GCM – you will find the GVM upgrade doesn’t change this, so you still can’t exceed the original GCM

    Aaron

  • Brian Hoare September 19, 2019, 6:03 AM

    Great article and very informative. Thanks for clarifying what seems to be so confusing.

  • Aaron Schubert September 19, 2019, 6:38 PM

    Hey Brian,

    Thanks, and you are very welcome

    Aaron

  • Rob Anderson September 23, 2019, 5:52 AM

    Hi there. Very interesting article, many thanks. However you quote that the Mitsubishi Pajero has a towball weight of 180kg. Mitsubishi tell me that models from 2017 on have a towball weight of 310kg but confirmed that the previous models (eg 2012) have just 180kg, might be an idea to update the article? Cheers Rob Anderson

  • Aaron Schubert September 23, 2019, 7:15 PM

    Hey Rob,

    Thanks. This is why its so important that you look your own details up; it varies from year to year, and model to model, and sometimes affects your towing capacity at certain tow ball weights

    All the best
    Aaron

  • Wayne Perry October 5, 2019, 5:20 AM

    Hi Arron,
    When calculating the GVM, is fuel in the original tanks counted as part of the payload? This could throw things out by 100kg plus in some cases. I have always counted the unladen weight of the vehicle with a full tank. Thoughts?
    Cheers, Wayne

  • Aaron Schubert October 5, 2019, 9:24 AM

    Hi Wayne,

    In general, your empty weight is calculated with about 10 – 15 litres of fuel in the tanks, so filling them up will reduce your payload by anywhere from 50 – 150kg depending on how big the tanks are.

    Cheers
    Aaron

  • Phill January 28, 2020, 2:41 PM

    My tow ball weight is greater than that identified on the plate but below the vehicle manufacturers specification – am I legal. The gross is ok

  • Aaron Schubert January 28, 2020, 3:14 PM

    Hey Phil,

    Which plate are you talking about? If its the one on the van, that is the unloaded weight and it will go up from that as you load gear in. As long as you are under the tow bar and vehicle’s tow ball weight you should be fine

    All the best
    Aaron

  • Mark Howland March 14, 2020, 5:10 AM

    Thank you for the article. Just about to head off for about 4 months on the road. So far, on our short trips, we are totally under weight. This trip, we will be carrying extra stuff, so keen to see what weight we will be. We live close to our local tip, which has a full weigh bridge. As long as you don’t want a print out, it is free to use! I will be keen to see what we weigh this time.
    cheers
    Mark

  • Aaron Schubert March 14, 2020, 9:21 AM

    Hey Mark,

    You are very welcome. Good to hear. It’s always interesting driving onto a weighbridge and seeing how close your estimates are!

    We also use a free one near us

    All the best
    Aaron

  • Fridge WA March 19, 2020, 3:44 PM

    Thanks Aaron,

    Your article is great – the fog is beginning to lift a little (Payload, ATM,GTM, ATM, GVM, GCM, TBM) starting to mean something.

  • Aaron Schubert March 19, 2020, 6:11 PM

    Hey mate,

    Good to hear. All the best

    Take care
    Aaron

  • Arnon April 5, 2020, 9:37 PM

    Hi Aaron,
    Your articles are great, and its becoming a bible to me.

    Be safe,
    Arnon

  • Aaron Schubert April 6, 2020, 2:49 PM

    Hey Arnon,

    I’m glad you enjoy them.

    All the best
    Aaron

  • Dave April 27, 2020, 7:04 PM

    Please describe the most efficient method of weighbridging a vehicle/caravan combination. Our local WB is always busy and I doubt the operator would be happy with me doing multiple passes, including unhitching van on the WB.
    Also please advise the likely weight of my tub liner.
    Dave (2014 2.5 D40 Navara)

  • Aaron Schubert April 27, 2020, 7:42 PM

    Hi Dave,

    To do it correctly, you have no choice but to do it slowly and with multiple passes. Alternatively, find a different weigh bridge, or see your local Pedders branch that can weigh it all for you (or a mobile weighing company).

    In regards to the weighbridge:

    Firstly, drive on with the van attached, but just with the front 2 wheels on on the weighbridge. Get that weight. Then, drive on with all 4 wheels. Get that weight. Then, drive on with the caravan and vehicle attached, and get that weight. Then, detach the van, and move the vehicle and get that weight. Lastly, get just the vehicle weight without the van attached.

    With this, you should be able to work out your Front axle weight, GVM, ATM, GCM, Tow Ball weight and rear axle weight

    If the tub liner is a normal plastic one on a dual cab ute it won’t weigh more than about 10 – 15kg

    All the best
    Aaron

  • Dave April 29, 2020, 7:31 AM

    Thanks Aaron. On the first pass as described above, after getting the combined car and van weight, would moving the vehicle off the WB still attached, enable the calculation of the necessary figures.
    Thanks for your help.

  • Allen Wheatley May 13, 2020, 7:09 AM

    We are looking at buying both a tow vehicle and off road camper trailer. I have read a myriad of information about weights, most if which is completly confusing. This article is quite clear, well writen and informative with a true sense if authoritive knowledge.
    Can you tell me though, are data plates ( nname plkates) on trailers legal documents or just general information?
    If they can be incorrect, what is the best wasy to find out a trailers weight data, particularity if it is second hand?

  • Aaron Schubert May 13, 2020, 6:40 PM

    Hey Allen,

    Thanks for the comment. Technically they should be correct, but only when the trailer rolls off the factory floor in its original condition. The problem arises when people add extra accessories into their package, or they add them after the fact (or secondary owners do it and so forth). The best caravan manufacturers in the business will guarantee a weight, and just prior to pickup will take it to a weighbridge, and get the data plate done based off the results.

    Really the only way of determening whether it is correct or not is to take it to a weigh bridge. I wouldn’t touch a second hand trailer without confirming the weight is correct. You can do this by finding people with the same van that has been weighed, and ensuring there is nothing significantly different, or just tow it to the local weigh bridge.

    All the best
    Aaron

  • Allan Whitbourne July 22, 2020, 10:26 AM

    Hi Aaron, interesting read, thank you. Owner of 2012 Prado with manufacture GVM = 2990kg and towing capacity 2500kg & tow ball 250kg and a 19’6″ 2017 Crusader caravan. Fully loaded the weighbridge weights are all under the manufacturers weights including the GCM:-
    Prado, GVM – 2620kg and tow ball – 230kg = 2850kg unhitched. Crusader, GTM – 2440kg unhitched. To work out the legal weights, is the tow ball weight added to the vehicle as you have indicated or is it added to the caravan to get the ATM figure??? Also, are the above figures legal for towing??? Thanks

  • Aaron Schubert July 22, 2020, 7:09 PM

    Hey Allan,

    The tow ball weight comes off your payload, and is considered in your GVM. It is not considered in your GCM. What is your actual van weight when loaded? If its over 2500kg you won’t be legal. Your ATM is the total van’s maximum weight (including the tow ball weight) and your GTM is the maximum weight you can apply to the axles (as in tow ball weight not considered).

    All the best
    Aaron

  • Allan Whitbourne July 23, 2020, 7:57 AM

    Hello again Aaron, to answer your question my actual van weight loaded is 2440kg but if I add the tow ball weight 230kg it is over 2500kg (illegal).
    If the tow ball weight is considered in the GVM of the vehicle and also in the ATM weight of the caravan doesn’t that mean the tow ball weight is in the calculation twice???
    Cheers

  • Yvonne October 16, 2020, 3:20 PM

    I have heard the the tow vehicle should be heavier than the caravan
    Is this correct

  • Aaron Schubert October 16, 2020, 5:00 PM

    Hi Yvonne,

    Its not a law, but it is good advice. Towing a much heavier trailer allows the tail to wag the dog, and not the other way around.

    All the best
    Aaron

Leave a Comment