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 …

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Apr 16 2020
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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 3800KG200 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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