GVM upgrades that exceed maximum axle weights – are they legal?

This is a question that has come our way a number of times, and I thought I would do some research to try and get some answers. 

Back to the start – What is a GVM upgrade

A Gross Vehicle Mass (GVM) upgrade is designed to legally allow you to increase the maximum amount your vehicle can weigh fully laden, from the manufacturer specified weight.  It is often necessary for people that heavily accessorise or modify their vehicle because it otherwise exceeds the manufacturer GVM, which is illegal and can have serious implications for you if caught, or if you have an accident.

When is it nationally approved, and when is it state approved?

There are two ways to conduct a GVM upgrade, with different legal implications.  If you get the GVM upgrade done prior to the initial registration of a vehicle (IE when new), then your upgrade can be conducted using a process called Second Stage Manufacturing, which makes it legal in all states in Australia because it actually gets a federally approved compliance plate that states the upgraded GVM as standard.

If you upgrade your existing registered vehicle, you will get a mod plate that confirms the upgrade, but it is only legal in the state that it is registered in.  I.E – If you have a GVM upgrade in NSW, and then move to QLD, you will need to complete the process again.  This is because pre-registration, vehicles conform to the national legislation, but once registered they are subject to state legislation.

Why the concern about Axle weights and GVM?

The concern comes from the fact that a number of the GVM upgrade kits available from suppliers exceed the maximum axle loads as specified by the manufacturer.  Now some of these kits (and I’ve heard Nissan mentioned) require bracing to the axle to be fitted as part of the upgrade.  But others sound like they are simply increasing the max axle weight by writing on a placard a new weight which exceeds the manufacturer recommended limit.  And this raises a number of questions.  Is this legal? Who is responsible if this fails?  Is this right? 

See below for a quick table on weights and GVM upgrades available – please note it is not exhaustive.

Make                             GVM         Max Axle weight       GVM upgrade

Ford Ranger PX                   3200KG            3330KG                       3500KG

Nissan Navara NP300         2910KG            3020KG                         3070KG

Mitsubishi Triton MR      2900KG            3200KG                         3200KG

Toyota Hilux KUN26R*        3000KG            not confirmed             3500KG

Toyota Landcruiser 3300KG            3580KG                         3800KG
200 Series*

Isuzu Dmax                            3050KG            3220KG                         3600KG

*Note: the Toyota figures are not confirmed in any brochure, so I had to do some digging to get them. 

In all cases except the Triton above, the GVM increase exceeds the manufacturer stated max axle weight.

How is the upgrade possible, when in most cases it appears that the upgrade doesn’t actually strengthen the axle?

I spoke to my local Pedders outfit and asked them about the outcome, and I also went to Lovell’s springs website to see what information they had.  The Pedders guy said that on the Nissan kits they strengthen the axle, but on the others they simply put a new placard on the vehicle.

While that seems ludicrous, his explanation was that independent engineering testing has been done on the axles of each vehicle to determine that the axles can take the additional weight, and then these new weights have been certified as safe through government channels upon provision of the test data, and then Pedders licensed to perform the upgrade.

Similar information was available on the Lovell’s site, which stated that they had completed independent testing to receive certification to complete the upgrade. Lovells went one stage further to say that they would cover warranty for any axle issues experienced, which raises a very good point about responsibility – What if my axle fails?

It appears that independent testing has confirmed that most axles are capable of taking more weight than manufacturers specify, and that they apply significant safety margins here, which would explain why no mods are needed to increase the loading for most vehicles.

The burning question though, is what happens if your axle fails under a load that exceeds the manufacturer specification after the upgrade.  I’m reasonably confident that a manufacturer would not cover warranty because you’ve exceeded their maximum stated specification.  But from your point of view, you’ve received certification that the vehicle can legally carry more weight!  The truth is that you would have to chase the person that performed the upgrade and certified it, and then prove that you didn’t exceed their maximum loading.  Not impossible, but there is definitely not an easy road here, unless you have had someone like Lovells state they will honour warranty.

And what about my insurance?

As part of the GVM upgrade, your vehicle will get a new GVM mod or compliance plate, and revised axle loading placard too, which means that your vehicle is legal, at least in your home state.  The issue that will likely arise is that you’ve now modified the vehicle from its standard specifications, which may means that it falls outside the underwriting guidelines for a regular insurer.  In laymans terms, it may make your vehicle un-insurable with a normal insurer – you’ll need to talk to them about whether they cover this sort of modification to confirm.

The good news here is that Club 4X4 specialises in insurance for 4X4’s, and we can cover a GVM upgrade – in fact, we can also add the cost of the upgrade to your sum insured, to make sure that you have cover that represents what you’ve invested in your vehicle.


To seek clarity on the issue, we’ve reached out to the national body for comment, and will update you with their response.  It does appear though, that the axle weights get an increase legally as part of the upgrade, regardless of whether any work is done to them.  I’d recommend asking about warranty if they fail though, because a manufacturer will likely only warrant the vehicle to the Original Equipment specifications.  And don’t forget to make sure that your insurer will still cover the vehicle after it is modified (unless you are with Club 4X4, in which case you should call us to add the cost of the upgrade to your sum insured).

Would love your thoughts, comments or experience on this matter below.


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Comments 44

  1. Hello Aiden with regards to your comments about legality if the vehicle is registered by the state they are a bit misleading. It is my understanding that if the vehicle is state registered and has an upgrade it is still legal throughout Australia but if you move interstate to live or sell your vehicle to an interstate buyer then you will have to get it recertified.
    Regards William

    1. Post

      G’day William, thanks for clarifying. Yes you are right – you can drive it legally in other states, but not register it if you move without recertification.


    2. I may have to disagree with this. My belief is that there exists an understanding between the States that if a vehicle has been legally registered in one State the others would accept the modified vehicle for registration by the current owner into another state if they are moving there with no recertification required. Just another possible grey area. I went with a Sixwheeler at 4830GVM. Its also worth noting that only 10+ years ago every VACC Victorian certified engineer would have nothing to do with GVM upgrades. I know this because I officially contacted everyone of them in writing attempting to get a GVM upgrade for my former Nissan. Now there is money to be made so its open season. Funny how that happens. Power of the all mighty dollar.

  2. thanks Aiden
    I believe another issue that isnt taken into account is the amount of vehicles that have had these GVM upgrades and using the incorrect wheel offset and very large tyres which look great but some much more extra stress on the axles which will lead to a premature failure and they wont be covered by either the manufacturer or the insurer.

    1. Post

      G’day Wayne,

      Thanks for the tip – the guy at Pedders did mention this. Might have to speak to an engineer about how they affect stresses put onto the axle!


  3. Hi Aiden,

    I think you’d better do some further research on the matter.

    I’ve had a post registration GVM upgrade done on my LC200 and the Engineering Certificate quotes the upgraded GVM and GCM for the vehicle and also provides revised axle loads for the front and rear axles of the vehicle. Funnily enough, the total load rating for each axle did not change significantly; the front axle increased by 100kgs and the rear axle only 50kgs over the manufacturer’s rating.

    The GVM is not an axle load – it’s the allowable gross mass a vehicle can legally be loaded up to across two axles and in the case of the LC200, namely 1,800kgs on the front and 2,000kgs on the rear = 3,800kgs.

    If I exceed either the front and/or rear total axle loads quoted on the Engineering Certificate I might have a problem which is why I’ve put the vehicle over a way bridge before undertaking any significant trips when heavily laden. I need to check my individual axle loads to make sure I’m under the approved GVM and the individual axle loads. The GVM upgrade does not mean you can add all the extra weigh over a single axle (usually the rear) because it’s the combined axle loads that have been increased.

    Cheers and happy researching.

    1. Post

      Hi Rob,

      Thanks for the comment. I was never suggesting you can go over the individual axle loads – well aware that you still need to work with them, so if it came across that way I’m sorry. Regards,


  4. I have had a small GVM upgrade done to my BT50, from 3200 to 3325. The original upgraded ARB 40mm raised suspension was good for this small upgrade so I only paid a very reasonable engineering fee. However the Engineer explained to me that the extra loads must be applied proportionally to front and rear axles and because I have an ARB steel bullbar and winch he could not give me the 3400kgs I was after due to the ‘front’ axle design limit being met at 3325kg overall GVM. So I always wonder as does my Engineer just how many other companies have been able to hand out 3500kg GVM’s when clearly the front axle load limits are met and exceeded. We wonder just how long the wheel bearings will take the extra punishment? Just how did Lovells 3500kg GVM upgrade for example get approval for a front axle specs upgrade when nothing has changed from the original design limits. Only time will tell but I was not prepared to take the chance and have now removed a few things to make the lower GVM acceptable.

    1. It was reasonably well known in industry circles, that the Ford Ranger and BT50 were pretty much maxed out on the front axle limit, by the addition of a steel bullbar and 2 people in the front of the vehicle. Other accessories added or weight transfer from any weight transfer type hitch, can put the front axles over the manufacturer spec. quite easily. Definitely still a lot of grey in this area.

  5. Hi I have a 76 series landcruiser modified to do remote area travelling so it’s had a chop to put a tray in and has a Dana 60 diff with all the mods around the vehicle to suit I did this because I have bent and broken my rear diff clean in half I’ve been doing this for 30 odd years and never had this problem I do know about weight factors and shock load etc but in my view and I have said this from day one the rear diffs have for some reason got extra flex that makes them weaker put extra fuel a fridge a little extra water your camper hooked up and I’m around 3800kg so now with gvm of 4700 kg and everything upgraded to suit it not only drives sweet but is safe and reliable in th bush cheers Gordy

  6. I’ve seen one of those engineering letters, for a front axle on a Land cruiser GXL tray. It clearly listed the stock GXL wheels and tyre sizes . The vehicle I was looking at had bigger rubber and steel wheels fitted by the dealer after the GVM upgrade. Leaving me to wonder what is legal and who is responsible.

  7. I had my gvm upgraded to 4495kg. This was achieved by adding a lazy axle to the vehicle. This was engineered and fitted by six wheeler conversion in Toowoomba. It comes with all the appropriate Qld tpt dept accreditation. If you want some more homework you could visit mike and the team at six wheeler conversion in Toowoomba.

  8. I heard, back in 2013, that a particular GVM upgrade on a Cruiser Ute stated that there was to be No Bullbar nor 3rd passenger to keep the front axel legal.

  9. Hi Aiden
    we have an ARB gvm upgrade on our 2015 D max,
    and the upgrade is up to the manufactures specs at 3220 kg

  10. I went through the whole process back in 2012 with a LC 200. I went with the Lovell’s GVM (after 1st rego) and it opened a can of worms. Seems I didn’t do enough research.
    They didn’t tell me (because I didn’t ask??)
    -That the engineer would put 6800kg in the GCM (nowhere in the Toyota handbook for otherwise was this figure quoted). This ment my towing capacity was smaller if I loaded the LC to new GVM.
    -Secondly if you wanted to get anywhere near the new GVM figure you had better put a lot of the weight on the front axle (Defender style spare on the bonnet?!) because the rear axle was maxed out before I even hitched on my van. Then the rear suspension sagged 50mm when I was still 400kg off GVM. After a lot of trips to the weighbridge I ended up selling it with only 20,000 km on it and bought a RAM 3500. Best move I ever did. BTW after owning the RAM for 3 years I lost $500. Don’t even ask what I lost on that LC…….

  11. Has anyone considered unsprung weight?
    Not all of your gross mass is suspended on the axels, especially with big tyres and wheels.

    1. Post

      Hi Matthew, thanks for reaching out. The unsprung weight still counts in your GVM! And yes, it needs to be considered…

  12. Hi I had an upgrade 18 months ago, Through lovells Carrum Downs in Victoria on my 2017 wild track, after the upgrade I went to the local Vic Roads to re register my vehicle and They issued me with new weights and a plate, best thing I ever done now I can tow my 25 foot silver line out back down the highway and be legal and I might add the people were great to deal with.

  13. The other thing the needs to be considered is wheel and tyres. I have a 3850kg GVM upgrade on my LC200 and when the engineer inspected the vehicle. the first thing they looked at was weather or not the wheels and tyres were rated to or exceeded the new GVM . Just another thing to consider along the way.

  14. Hi Aiden.
    From a warranty point of view I am just about 100% certain that any manufacture would not pay a claim on ANY vehicle (not just an axle failure) that has had a failure due to being over loaded. Now just because a vehicle has had a GVM upgrade does not automatically mean it has been over loaded from the original factory specs. But, from a manufactures point of view, any vehicle that has been modified to carry more weight than designed by the maker, Would or Has been over loaded by more than what it was made to carry…correct. So surely this over loading by the GVM UPGRADE could / would contribute to premature failure of just about anything in the driveline, as the driveline has not been designed or tested by the maker beyond what they have stated. So again it opens up a can of worms.

    1. Post

      Hi Matthew, thanks for writing in. This is where it isn’t black and white. Your driveline has a GCM, which is far greater than the GVM – that is it can pull much more than the weight the GVM upgrade adds, and your GCM can’t be upgraded. So the loads on the drivetrain won’t exceed the manufacturer thresholds. However, yes increased weight on the axles, chassis etc does potentially cause more wear and tear. But the GVM certification, and indeed the certification the upgrading company receives to do the upgrade requires engineering testing to prove it is still within the safe limits of the vehicle. If it fails, will the manufacturer want a bar of it? Probably not, but there would then potentially be a liability on the certifier. Still challenging to get covered unless the certifier provides a guarantee. But that’s what you pay for – someone else has given you the tick to say this is ok and the vehicle can handle it – if it doesn’t, and you’ve stayed within the upgraded limits, the upgrading Organisation would have to bear some liability…

      1. To Jay,
        First time I have heard of people losing on a LC200 or Prado – not sure why as they always hold their price no matter what model you buy.

  15. In your blurb you forget to mention that to do the upgrade the front and rear springs and shocks are change to maintain a good ride height when loaded

    1. Post
    1. Post

      Yes that is correct Steve, which means that you actually reduce your towing capacity by the amount of the upgrade if you load the vehicle to GVM. GCM is fixed no matter what.

  16. I had my 2018 Dmaz extracab with alloy tray (with only 18000k’s on the clock) modified by Lovells Carrum Downs for a GVM upgrade to 3600kg as well as raising the GCM to 7000kg (less tow ball weight). The vehicle is as also fitted out by them with TJM accessories that include long range fuel tank, steel B/B side steps and winch. I’ve also had the tyres replaced with 245/75/16 10 ply tyres as a requirement of the upgrade. After the upgrade I’ve installed a new aluminium fitted out canopy with fitout has been installed. Lovells have confirmed that the upgrade has need cirtified and engineered and will not be any warranty issues on axles and running gear, so I’m more than happy. I am also insured with Club 4×4 insurance and have also notified Club 4×4 insurance in writing of all listed modifications as well as the GVM upgrade and costs of all additions. I put a lot of trust in the experts and invested a lot of hard earned cash into the Dmax and can only hope that should I have a warranty claim or an insurance claim I won’t have any issues. I do not intend to go anywhere near the revised GVM nor the higher GCM as I don’t tow a caravan nor a trailer, so breakage of any running gear shouldn’t be an issue. Time will tell.

    1. Post

      Hi Cleve,
      Thanks for sharing. I’d be very interested to see the documentation around the GCM upgrade because my understanding is that the law doesn’t allow you to increase the GCM from the manufacturers original specifications, and while this has been a grey area, there is clear direction from the Govt saying that GCM can not legally be changed. Perhaps this was done before the clarity was provided by the Govt last year?


      1. Hi Aiden I’d be happy to talk directly if you can call me on my contact mobile number I can share the data I’ve got. As you may have noted in my previous reply I’ve had quite a bit of mods done along with paperwork confirming GVM, axle load increases as well as GCM upgrade. Club 4×4 have not indicated to me that I’m not covered so I have to assume all is good with Club 4×4 on my modified vehicle!!! When you call I can discuss this as well as my Lovells/TJM paperwork.
        I think you’ve written a great article on this subject , this will most certainly raise a lot of concern and further discussion.

    2. Think about it from a manufacturers perspective.
      – Spends millions on development
      – Leave a nice leeway on weights, capacities, drivetrain stress points, good mark up on what it can do within vehice limits
      – Random consumer talks to Freddie the mechanic who says he can “upgrade” your car
      – Decides to spend money changing core areas of the driveline, that can affect engine, gearbox, suspension, chassis, not to mention everything else along the way.
      – Something breaks that can be AT ALL linked to the modification, towing, carrying etc
      – you want to make the manufacturer fix it.

      Would you?

      Not a chance in hell…. I know that if a seat falls out, if there is an issue with the fuel system, etc – anything that cannot be linked to any upgrades, should by MOSt makers, be covered… But I am absolutely astounded by anyone thinking that a car /vehicle maker would entertain fixing something that would not have otherwise broken or had issues…

  17. A GVM upgrade is done using a branded suspension change over. What is the situation down the track when the struts or springs are worn or sagging and are replaced by those of a different manufacturer? Is the upgrade still legal? Another can of worms?

    1. Post

      Good question John – you’d have to make sure that the replacements are equivalent in load rating to be sure that the upgrade is still legal. If you chose lower rated items, then technically you could have an issue. Not sure about the legal ramifications of that though…

  18. Hi Aidan
    I have just had a 300kg (now 3500kg) Pedders GVM upgrade on my BT 50 so I can carry a Slide-On Camper. The new Placate stuck to the car shows a rear axle increase of 200kg (now 2050kg). The new total front & rear axle load is 3530kg.
    The ride is great with the Camper on however it is extremely uncomfortable with no load. Would be dangerous in wet weather. I have notice that this is why ARB’s equivalent upgrade states you must carry a minimum load of 600kg.

    1. Post

      G’day Greg,
      Thanks for the comments. This is correct – the suspension you talk about is designed to operate with constant load, and without that would be hard as a rock. This is the conundrum manufacturers face – the Ford Ranger Raptor is so good offroad because of the suspension setup, but that isn’t designed for heavy constant weights. There is no perfect solution unfortunately! Perhaps keeping a few hundred kilos in the rear all the time will help?


  19. Hi Aiden, I was told by my neighbour that his son (here in Qld) , purchased his 200 series straight of the boat, Never been registered, had an upgrade done then was able (I`m told) could get an upgraded GCM. Have you heard of this??

    Cheers mate


    1. Post

      G’day GG,

      I’ve never heard of a GCM being upgraded legally, however, second stage manufacturing, which is clearly what he’s had done might allow for this. Let me do some digging.


    2. Post
      1. Good morning Aiden, thanks for checking the GCM upgrade story for me. I was thinking the same, no such animal.

        Cheers mate

  20. Hi aiden,

    A lot of people don’t realise your ball weight comes off GVM and gets added to rear axle load. Usually multiplied due to the overhang over the rear axle. Acts as a lever. Just thought I’d add that.

    Most people don’t realise for a Ford ranger to tow 3500kgs legally it can basically only have a 2 people and full tank of fuel in it. No accessories or other weight on the vehicle.

    It is very annoying that as a consumer, these car manufacturers still sell cars with axle loads and GVM’s that are not high enough. So many people are unawarely driving around over the specified loads and manufacturers know this! Yet they continue to sell cars that don’t meet the mark.

    I have a GQ patrol that I have tried to VASS engineer it here in VIC to try and keep legal, but they don’t care or have the time for my business. Seems like it is all too hard for them…. so I know it is over GVM but there is nothing I can do. I have put braced GU diffs which have an axle rating of 500kgs more without bracing. This included with upgraded brakes and suspension make zero difference legally…

    Makes for a good campfire conversation…


  21. My brother is planning to increase the load of his truck, so I do recommend him to go for GVM upgrades. He is planning to go to his mechanic this weekend. I will encourage him to look into GVM upgrade to help him increase his weight capacity.

  22. Hi Aiden,

    Great read, I’m researching this topic and you have provided valuable information. Just so this isn’t a one sided view, I did have the Dual Cab 4wd, extended chassis, canopy, airbag suspension, fully kitted for touring, all the fruit so to speak.

    I think the elephant in the room needs to be addressed. Vehicle manufacturers sell the hype that the new {insert 4wd model here} can do everything you want it to do. They smile and take your money. The new owner now realises that the new car can’t do what they want it to do and drop more money to band aid the problem( into the open arms of a suspension company), and ultimately running the loaded vehicle at or near the new GVM. There has to be some acceptance on behalf of the owner too, as they have now purchased vehicle that is not fit for what they want to do. But, ‘I’m legally allowed to do it’.

    Legal vs. safe, well that’s a different kettle of fish. As you state the GVM upgrade testing assumes a factor of safety when the axle is determined that it can take the extra load. But, what is that safety factor? The rigging industry has this clearly documented in the x3 or more factors. What is the axles load rating safety factor?

    Have a look at the dual cabs bending at the cab, I’m sure there is a safety factor in there somewhere. Or is it the manufacturer bean counters worked out the bare minimum required to do the job and just did that. Does the axle load rating fall into this category? It seems that with the testing done to achieve the increase in GVM, the axle load ratings didn’t have much extra to offer, given that the increase to the GVM in most cases is only a couple of hundred kilos over both axles. There doesn’t appear to be much bang for buck.

    Lets look at the money side of it. So, please correct me if I’m wrong, I’m going to drop say $100+k on a vehicle, add accessories to the value of say $50+k (in the case of some fully worked 4wds, a LC200 or 79 series at $250k is not a shock), then weigh it to find out that I don’t have enough payload left to put my family and belongings in it, then hook up the van and find that I’m now way over the GCM. I’ll then go and pay for some suspension upgrades ($more money), get a little blue placard that says its all ok, drive off into the sunset, and hoping that I don’t need any warranty work done, and safely do it whilst travelling at 100 on the highway.

    Your article confirms my decision. I’m off to the {insert heavy truck brand here} truck shop to buy a purpose built vehicle that doesn’t need a GVM upgrade, one that’s built to handle the increased GCM, axle load ratings that I could possibly not overload with what I want to do. And I’m sure there is a safety factor in there somewhere without a band aid solution. I’ll drop some money on the super singles (doesn’t everyone put new wheels and tyres on the new ride) and upgrade the suspension to parabolics. With the left over cash, I’ll buy a small run-around car for those trips to get bread and milk when I’m not travelling.

    I’m sure this GVM/GCM/GTM/ATM/axle loads subject is heavily debated around the campfire. Pun intended.


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