32 ways to make your 4WD illegal (and void your insurance)

There are hundreds of thousands of 4WD’s in Australia, and a significant portion of them are not legal in one way or another. Sometimes the reasons are minor and relatively harmless, and other times the risk passed onto the driver when on the road is substantial.

A 4WD that isn’t legal can result in some hefty fines, liability and other truly nasty consequences if something goes wrong.

If you have an accident with a vehicle that is illegal and your insurance company or the police prove that the modifications contributed to the accident you can be in a world of pain.

People have literally had hundred thousand dollar claims walked away from because of this, and if you injure someone or worse you could end up in a lot more than just financial trouble.

In this post, we cover 32 ways to make your 4WD illegal!

Please do your own research for the state you live in, as conveniently the 4WD modification laws in Australia are not uniform, and what is legal in one location may not be in another!

Is your 4WD legal?
30 ways to make your 4WD illegal

Exceed the maximum suspension lift

One of the most common ways to make a 4WD illegal is to install a lift kit that is above and beyond what you are allowed to do. In many states, a maximum of 50mm suspension lift can be installed, but it doesn’t end there.

In WA, you can only lift your vehicle by 50mm by way of tyre size increase, body lifts and suspension lifts in combination

That means if you fit a 50mm suspension lift (or 2 inch as they say) that’s it – you can’t raise it any higher. In other states, there are regulations that relate to whether your vehicle has ESC (Electronic Stability Control). 

You can usually get engineering permits that allow for larger suspension lifts, but it very much depends on what other changes have been made, and whether your 4WD has ESC.

Bottom line, be careful of how much you lift your 4WD, or it may end up unroadworthy.

4WD lift kit
Got lift?

Remove the DPF

Diesel Particulate Filters (DPF’s, or even DPD’s as some brands call them) are in pretty much every new diesel 4WD that you purchase today, and they’ve been common in many modern diesels for about the last 10 years.

They catch the nasty particles that a diesel emits, and do regular burns to get rid of it. They were brought in to meet tightening global emission regulations, and anything relating to this is a big no no when it comes to modifications or removal.

A lot of people are physically removing their DPF due to ongoing problems that they cause across a wide range of models. If you’ve done this, your vehicle is now illegal, and the fines are astronomical.

I have seen the transport authority checking for these on the odd occasion, and I guarantee that they are going to be looking for emission regulation changes more often as time goes on. To clarify, a DPF delete is not legal.

A DPF is super expensive to replace, and having to buy another one is probably not something your back pocket is going to like.

Beyond this, these emission controls have been brought in to better the world’s emissions, as diesel fumes have been registered as a carcinogen, meaning they cause cancer.

Overload your roof

Every 4WD comes with a maximum roof loading capacity. This includes the weight of your roof racks, and is in place to ensure you don’t make the vehicle handle unsafely, as well as stopping damage occurring to the roof.

Most roof capacities are 100kg, with a couple 150 and 200kg, but having excess weight up top is asking for trouble purely from a fuel economy and centre of gravity concern.

If you don’t know what the maximum roof capacity is, or you want to know more, check this post out; Roof Rack weight limit.

Roof racks on the 80 series
Excess roof weight can make your 4WD illegal

Block or turn off the EGR

Just like the DPF, your EGR (Exhaust Gas Recirculation) is a part of the emission control system on most modern diesel 4WD’s.

It takes a portion of the exhaust gas, and feeds it back into the intake. This does have some benefit, but its essentially feeding some dirty, sooty air back into your intake which isn’t great.

Combined with the oil mist that comes from your crank case, you soon end up with a significant build up of Vegemite looking substance blocking air flow. A quality catch can (like a Provent 200)will stop most of the build up, and allow the EGR to be left alone and to do its job.

Provent 200 catch can
A quality catch can is the only legal way of mitigating the build up in your manifold

There are thousands of people who have either electronically turned off the EGR by way of a tune, or a cable/diode to trick the ECU into keeping it shut, or simply by blanking it off with a plate. This is commonly known as an EGR Delete.

You’ll see people fit all sorts of plates, and some models don’t take too kindly to having the EGR blocked off so people leave a tiny hole in the middle.

Any modifications to your EGR will land you in sketchy territory, and with the way emission controls are going checks are going to be done more often, and you could end up in hot water.

Again, you have a moral obligation to leave any emission control devices to do their thing, or you are contributing to additional, harmful emissions.

The best thing to do is fit a quality Catch Can and leave the emission controls to do its thing.

Install tyres that are too big

There seems to be a big fascination with fitting the biggest tyres possible, along with a huge lift kit. There’s a lot of downsides to some 4WD modifications, and because of this, there are laws limiting the tyre size that you can run.

In general, a 50mm increase in diameter is permitted (25mm increase in vehicle height) but this gets more complicated when you combine it with a suspension lift (and occasionally you can go over 50mm tyre size increase).

Bigger tyres increase your centre of gravity, reduce your braking capacity and make you burn more fuel. Asides from this, if you exceed the maximum tyre size your vehicle becomes unroadworthy, and puts you in significant risk.

If you have an accident, and the insurance company (or law for that matter) deems that the larger tyres contributed to the accident, you can be liable for the cost of the accident.

Running the next size up tyre can be useful, but they don’t come as a free lunch. You have to pay for it in one way or another!

Jeep 4WD big tyres
Big tyres will land you in trouble

Run wheels that are too great of an offset

There are limitations in Australia as to how wide your wheel track can be. In WA, you can increase it by 50mm. If you go from positive 33mm offset to negative 33mm, your wheel track will increase by more than 50mm and you have an illegal 4WD.

Beyond this, it will chew your wheel bearings out much faster, chip your paintwork without flares and draw a lot of extra attention. If you want to know more about this, check out Wheel Offset.

Offset wheels
You can change your offset, but watch the wheel track

Install wheel spacers

Wheel spacers in Australia are not legal. You cannot run them on road, and this is because there have been too many issues with them working loose or breaking and wheels coming off vehicles.

For those running Land Cruisers with different differential widths, a cheap and easy way to overcome the problem is to install spacers.

This isn’t legal, and despite those who’ve been running them for years saying they are fine, they are not. The only alternative is to run different offset rims to counter it, or to get the differential widening kits that are ADR approved (and mega expensive!).

Remove your rear mud flaps

If you’ve ever driven behind someone on a gravel road without rear mud flaps, you’ll know why they are so important.

In WA, your rear mud flaps must be no more than 300mm from the ground, and they must cover the width of your tyre. If you change tyre sizes, you should be getting wider mud flaps.

Don’t rip them off; they are one of the more useful things on a 4WD for those travelling around you!

Custom mud flaps
Custom mud flaps on our 80 Series Land Cruiser

Cut or modify the chassis

The moment you go near your chassis with a grinder, welder or oxy torch without engineering, say good bye to having a legal 4WD.

There are a number of reasons why you might do this, like solid axle swaps, chassis bracing or extensions or suspension changes, but to do it properly you need an engineer to sign it all off. 

Even the cheap chassis bracing kits require an engineer to sign them off, as you’ve played with something of incredible importance.

Chassis need to flex and take the rigours of 4WDing without falling apart, so there are some engineering laws that need to be followed and signed off.

Install fishing rod holders outside the bull bar

Fishing rods are a right pain in the backside to travel around with. In past years, you’d regularly see those with fishing rod holders attached to their bull bar.

If they stick out forward of the bull bar, its illegal. This is due to the additional pedestrian risk if you were to hit someone. 

If you want to run fishing rod holders, you either need to mount them behind the bull bar (which is usually hard to do) or put them on your roof rack.

Fishing rod holders
Rod holders on our old Hilux, that are illegal

Install non ADR approved accessories

ADR stands for Australian Design Rules, and they govern what can and cannot be fitted to your 4WD. You cannot legally fit 4WD accessories to your 4WD that are not ADR approved.

This means custom bull bars, rock sliders, rear bars, roof racks and you name whatever else, unless it has Australian Design Rule approval, its illegal.

If you mate different brand name gear together, like an ARB Bull bar with TJM scrub bars, you’ll also not be compliant. Whilst I love the look of some custom bull bars, they are all illegal, and getting ADR approval isn’t the most straightforward thing for one off products!

If you want to know more about the many things to think about in a Bull Bar, check this out – What to look for in a Bull Bar.

ADR compliant modifications
ADR approved accessories are a must

Install an LSD in a vehicle that didn’t have it

One of the more well known Dmax issues is some of the 2012 to 2016 model rear differentials have a habit of failing very early (under 100,000km on the clock).

The hard facing giving up and then the diff turning into a pile of metal chunks. A lot of people are taking older model differential centres with LSD’s and fitting them as a replacement. 

Good thinking, except that it specifically says in the manual that installing an LSD in a vehicle with ESC (Electronic Stability Control) is not legal.

It interferes with the way the computer controls the stability of the vehicle, thus rendering it illegal. 

Do you have an LSD?
Fitting an LSD into a vehicle that doesn’t have it is illegal if you run ESC

Install HID or LED bulbs

This is a personal pet peeve of mine. If you install LED’s or HID’s into a 4WD that didn’t come with them, and without changing the reflectors, you’ve made your 4WD illegal.

The reason is real simple; your reflectors are designed to reflect halogen light in a nice, controlled beam.

When you install LED’s or HID’s it takes the light and scatters it in every direction possible. You can read more about this here; Are LED and HID Conversions illegal?

Sure, it might look brighter to you, but its also blinding for any oncoming traffic, and frankly dangerous. LED’s require self levelling headlights, and HID’s need reflectors that channel the light in the right direction.

Yes, you can adjust them down, but they are still substantially brighter than the OEM globe to oncoming traffic, and that’s not great.

Light conversion
If you are going to swap lights, keep them legal

Run the crankcase ventilation to the chassis

The subject of catch cans will fire a lot of people up, especially those who claim that running the crankcase ventilation hose to the chassis is the best idea.

Sure, you guarantee that no oil makes its way back to the intake, but its also irresponsible and dangerous.

Instead, the oil pools into your chassis, eventually dripping out onto the road for an unsuspecting motorbike or car driver to slip on.

Get a decent catch can like a Provent 200, and be done with it. It’s legal, its safe, and you won’t be putting other peoples lives at risk by dripping oil onto the road. 

Provent 200 in an Isuzu
A good catch can like a Provent 200 is the best way to catch oil mist

Spew excessive amounts of smoke

My old 80 Series Land Cruiser used to chuff a bit of soot if you gave it a boot full, but I’ve seen some 4WD’s (and not only old ones) that just about leave you ducking for cover when following behind.

If the back of your 4WD has soot on it, there’s a pretty good chance you have a problem. 

Excessive smoke can easily be reported by the public, and you’ll get a letter asking you to come in and get a roadworthy. Beyond this, excess smoke is a sign of something not being right, so its in your best interest to get it fixed!

Diesel smoke isn't great
Excess smoke like this will attract unwanted attention

Have tyres stick outside the vehicles body

If you want to attract the attention of the Police, fit tyres that are wider, or have a more negative offset and don’t install flares.

If you can look down the side of your vehicle and see any part of the tyres sticking out the side, its not legal.

Its super easy to spot this from a mile away, and when you have people running tyres 100mm out of the guards it makes for easy pickings.

I can tell you from experience that having tyres outside of the guards will land you with excessive stone chips on the bottom parts of your panels, as there’s nothing stopping little rocks flicking straight up.

Get yourself some aftermarket flares (or even Bunnings garden edging) to cover the tyres up, and you’ll attract a lot less attention.

Tyres outside the guard
If you tyres stick outside the guards, its not legal

Install too many forward facing lights

I chuckle every time I see a 4WD with a huge array of lights on it. In WA, you are restricted to a maximum of 4 additional driving lights.

If you put 4 on the roof, plus a light bar, you aren’t legal. With the quality of lights out these days you don’t need to run that many anyway, but there are limitations in case you weren’t sure.

Lights on a 4WD
Too many forward facing lights can get you in trouble

Add a light bar or spotlights in the wrong position

Beyond the above, you can’t fit spotlights or light bars anywhere you please. Again, this varies from state to state, so check it out. In WA though, you can run additional lights on the roof of your vehicle, or below the front edge of the bonnet.

You cannot install them so they protrude forward of the bull bar, or above the front edge of the bonnet. They also need to be mounted symmetrically, and in a way that isn’t going to hurt someone.

Where can you mount LED light bars and spotlights?

Light position for a 4WD
Light bars on top or in front of the bull bar are illegal.

Tow something beyond the capacity of your vehicle

Caravans and camper trailers are getting heavier every day, and people are often towing things they aren’t legally allowed to.

Every 4WD comes with a maximum towing capacity, along with maximum tow ball weight, GCM and a whole range of other figures you need to investigate.

I wrote a post about this some time ago which explains it all very simply – Towing Capacity; a simple guide to keep you legal.

Towing with a Pajero
Watch what you tow, as its easy and illegal to be over weight

Fit a tray that’s too long

There are some interesting restrictions when it comes to modifying your 4WD. One specifically relates to Utes, and how long the tray is that you install.

Everyone should know about the huge increase of dual cab Ute chassis bending in Australia, and this is part of the reason why you can’t fit a tray that is too long. 

The general rule is that the tray can be a maximum of 60% of the wheel base measurement overhanging the rear wheels. If you exceed this you end up with an illegal 4WD, and a much higher likelihood of bending something.

Tray length is important
A 1700mm tray, which is easily legal and still has plenty of overhang

Fit a body lift without engineering

One of the ways to lift your 4WD is to fit a body lift. It’s basically aluminium or plastic blocks that separate your body and chassis.

It’s a cheap way to lift a 4WD, that has a lot of downsides including the need to see an engineer, or get a permit to have it approved.

I would never suggest people run a body lift purely after having one in my Hilux and jumping through the hoops, but if you do, talk to an engineer first!

Overload your 4WD

You can see an overloaded 4WD from a mile away. If its setup with all the gear, plus carrying a couple of passengers and no GVM upgrade, you can guarantee its pretty close, or over the limit.

Every 4WD comes with a maximum GVM, and this includes every single bit of weight on or in your 4WD, including the tow ball weight.

If you take a 200 series Land Cruiser and put 5 adults in it, fill the fuel tank up and install a Bull Bar, you are probably illegal already, and that’s without a rear bar, second spare, fridge, second battery, scrub bars, side steps, 4WD drawers, food, water and everything else that is often in a 4WD set up for travelling.

It’s super easy to have a 4WD that is over weight (as I found out with our Dmax; you can see what it weighs here – Dmax weight for touring) and the road authorities are regularly pulling people over and weighing them these days.

This is another point that is extremely easy to prove contribution to an accident, which can pass liability onto you quick as a flash.

Do you know what your 4WD weighs?

Bogged in the 80
An over weight 4WD makes it easier to get stuck, and makes it illegal

Install extended shackles

If you are running leaf springs, one of the cheap ways to get more lift is to remove the factory shackles, and install extended ones. They can work well, but they are also illegal and not worth fitting, so save your money for the correct springs!

Do a solid axle swap without engineering

There aren’t too many modern 4WD’s today that are running solid front axles, and there’s a big obsession with them for serious, hard core 4WD tracks. A lot of modern 4WD’s have had their IFS (Independent front suspension) chopped out in place of a solid axle (often a Land Cruiser diff). 

This is not something the average DIY person would be capable of doing anyway, as it requires extensive modifications and needs to be done well without severe implications, but you need to get it engineered to be legal. 

Fitting a roof rack that is too big

In WA, you can’t install 4WD roof racks that are more than 2.5 metres long, or 150mm wider than the width of your vehicle. I’ve seen a few vehicles with racks that run the entire length of the vehicle, and that’s not permitted.

Roof rack size is important
Watch the size of your roof rack

Wire additional lights up incorrectly

Any aftermarket lights that you install should be wired up properly. That means they are attached to high beam, and turn off when you flick your high beam off.

If you are running work lights on the rear, they should be switched correctly too. 

Light bar wiring
All additional lights must be wired correctly

Not using extended mirrors when towing a wide trailer

By law, you need to be able to see past the trailer that you are towing properly. This applies mainly for horse floats and caravans/camper trailers, but a wide trailer will require you to fit aftermarket mirrors to maintain roadworthy condition.

This is so you can drive safely, and see who is behind you. If you can’t see those behind you (and reverse camera’s are not legal for this) then you have a problem.

Clearview towing mirrors
Clearview towing mirrors for a van

Running wheels that aren’t wide enough for your tyres

The wheels, or rims that you run must suit the tyres you run. Some people squeeze a 265/75/17 onto a 7 inch rim, but its not permitted, along with a huge range of other sizes and combinations.

There are tyre standards, and if you break them, your vehicle isn’t roadworthy. Most tyre shops can point you in the right direction.

Using incorrectly load rated tyres

Every tyre comes with a speed and load rating. This should match the weight and specifications of your 4WD. If you get a GVM upgrade, often the OEM tyres are not rated to a high enough capacity, and you need to change them. You can get the load rating off the sidewall of the tyre.

4WD tyre load rating
Make sure your tyres have the right load rating for your weight

Not distributing the weight properly

Dual cab Utes are notorious for poor weight distribution, but its very possible in wagons too, so don’t skip this. Every 4WD comes with a maximum axle weight for the front and rear of the vehicle, and then a Gross Vehicle Mass.

If you take the full payload of the vehicle and plonk it on, or behind the rear wheels of your 4WD you won’t be legal.

The payload expects you to balance the weight evenly over the 4WD, with some weight at the front, some in the middle and some at the back.

It is possible, and even easy to have a vehicle that is under GVM, but over on axle capacity and therefore still illegal.

4WD Weight distribution
Distributing the weight properly is super important

Swapping an engine without certification

Engine swaps are relatively common these days, with some pretty amazing changes and improvements being made. You are allowed to do a range of swaps, but what ever you do has to be signed off and engineered.

There are emission regulations that forbid you from taking an old motor and putting it in a new vehicle, and a range of motor limitations depending on where you live.

If you have the ability and need to do a motor swap, consult an engineer before you spend any money, or you may regret it down the line!

Duramax conversion
A Duramax engine conversion in a GQ Patrol

Ending the exhaust too early, or having it too loud

Exhausts are supposed to exit at least 300mm past the last passenger door of your 4WD. Single cab Utes can get away with them exiting before the rear wheels, but most other 4WD’s need to have them exiting near the rear.

This is common sense, as it prevents fumes from working their way into your 4WD and hurting the driver or passenger.

The exhaust level is also critical, and a good way to attract attention if you get it wrong. In WA, the noise level can be 90 dB, but this is measured from a range of angles under certain circumstances.

A loud exhaust is super annoying for long distance travel anyway, and will land you in trouble with Mr Plod.

You can do a muffler delete, but the restriction is in ensuring the noise levels comply.

Exhaust exit
Your exhaust must exit at least 300mm past the last passenger door

Installing a long range tank without certification

There’s a lot of 4WD accessory businesses out there installing a long range fuel tank without engineering or certification.

If you are going to get one, make sure that it comes with the correct certification or mod plate, or you can land yourself in hot water.

Why is it important to have a legal 4WD?

If you’ve made it this far, we briefly touched on why its important to have a 4WD that is legal. For starters, its the law, and what we should all be abiding by.

Beyond this though, there are a few far reaching implications that can badly hurt you as an individual.


When you take out a 4WD insurance policy, the fine print on every insurance policy in Australia states that you agree to have a roadworthy vehicle, and keep it that way (or words to that effect).

The moment you make your 4WD illegal, the insurance company has an ‘out’ when something goes wrong.

Now, they can’t say because you had a non ADR approved bull bar it caused you to back into a pole, but if the modification directly contributed to the accident you can be in a world of pain. Lets say you have big tyres and a huge lift, and you roll it coming around a roundabout.

Any smart insurance company (and they do this often ) is going to say the tyres and the lift caused the accident, sort it out yourself.

There’s some pretty expensive 4WD’s out there, and having to replace it without insurance would cripple a lot of people. However, take it a step further; what if you crash into a nice sports car, or you cause a multiple car pile up?

4WD insurance
If it all goes wrong, are you confident you are legal?


In a world where litigation is commonplace, doing the right thing is a pretty clever idea.

If you happen to hurt, or even worse, kill someone and your illegal 4WD modifications contributed to the accident, there’s a good chance you will end up under scrutiny, with a significant fine and even jail time.

There was a case recently of someone who had a vehicle accident and killed his passengers, and ended up in prison for it. Is this a risk you want to take, just to have a slightly larger tyre or bigger lift kit?


The moment you modify something on your 4WD, you can expect to have issues with your warranty. The reasoning is simple; time and time again aftermarket accessories muck with the OEM design and cause faults.

Technically you can’t have your warranty declined unless the manufacturer can prove your modification contributed to the accident, but its very easy for them to say it did, and for you to be left in a grey area.

I know all about this with the GVM upgrade done to my Dmax, which ended in 4 leaking transfer case seals being replaced.

After the first one Isuzu blamed the lift, and walked away from it. Now, given I couldn’t prove it wasn’t the lift, what could I do about it, except deal with it myself.

A leaking transfer case
If you modify your 4WD, expect a hassle when it comes to warranty claims. This is the oil leak from our Dmax transfer case.

Reliability and safety

There are a number of restrictions on 4WD modifications, which weed out the issues caused by cowboys doing things they shouldn’t.

The road is a dangerous place already, without people driving vehicles that are poorly or illegally modified.

That’s not at all to say that a highly modified 4WD cannot be legal, but there are lots that have not been done well and that shouldn’t be legal (and wouldn’t pass engineering if they tried).

Your safety, and the safety of others is super important, as is reliability. If I’ve learned anything from modifying 4WD’s, its that the aftermarket gear is always the first to give you grief.

So, the big question; is your 4WD legal?!

If not, seriously consider what needs to be done to make it legal. Keep it clean, tidy and drive sensibly and you’ll stay out of the police’s attention radar.

Often when you get pulled over and inspected for something small it can lead to much bigger problems being found. For more information, check out our page on 4WD Legalities.

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  1. Hey Ian,

    In WA, I believe it must end at least 300mm behind the last passenger opening (door etc). I can’t speak for other states, but you should be able to contact the road authority and clarify.

    All the best

  2. Ian Wallace says:

    G’day outdoor off-road enthusiasts…. My question is answered above however has left me unclear to what it means…I have an 1992 hilux 4wd,with an L67 and strengthen 4L60e, now, it’s an xtra cab, meaning it has the small parcel shelf with the fold up seat pads and the 1/4 window (fold out) after the driver n passenger windows. Some call this cabin type a king cab, others a space cab or like I previously said xtra cab.
    Not a single cab and definitely not a dual cab.

    I am in South Australia where the vehicle is registered, I’ve seen results n legalities on here regarding other states… is it ok to end yr exhaust with cats and a decent muffler INFRONT of the rear wheels?

    Any info/site links on this will be greatly appreciated.
    And remember, shinyside up guys n gals.

  3. Hi Reece,

    Given that the width from wheel to wheel on the rear is going to be wider than the cab, it would be illegal to fit a tray that isn’t wider than the cab. It has to cover the wheels, or you’ll get done by the police.

    I would ring a reputable tray seller, and see what they say, but ours, and probably majority of trays are wider than the cab; have a look at your local shops and you’ll see what I mean

    All the best

  4. Reece Spense says:

    Are there any roadworthy restrictions on the width of the ute tray (1800mm). Have been advised by mechanic that it needs to be same width as cab (1650mm) for roadworthy.

  5. Hey Mongrel,

    It’s an interesting discussion, and likely a very grey area. I think if you built a roof rack, and in an accident it fell apart and killed someone, you would have major troubles as you cannot prove it was built and designed to a relevant standard.

    Likewise, Bull Bars need to have the right coverage, and angle or they are not legal, and can injure a pedestrian much more than one that is compliant.

    All the best mate

  6. Hello Aaron, this is exactly the kind of detailed information I’m looking for, and would love to know more. The most important consideration really is insurance being valid, which could have far greater effects than any police fine. However I suspect you are taking too far with DIY work being illegal. Your words: “This means custom bull bars, rock sliders, rear bars, roof racks and you name whatever else, unless it has Australian Design Rule approval, its illegal.”
    To clarify, I reached out to Vicroads regarding my DIY steel roof rack and this was the response.
    “Thanks for your enquiry regarding a home made roof rack. Yes this would be fine providing the rack sits within the plan of the vehicle, it is secure, no protrusions that could hit a person or another vehicle, and it is non reflective.
    Vehicle Safety”
    I hope this helps someone else.

  7. Hey Bob,

    There’s a lot of 4WD’s out there that are stock, or hardly modified, but certainly plenty that wouldn’t pass the ADR requirements. Whether that makes them safe or not is another thing, but it certainly helps the economy with lots of money thrown around!

    I’ve always adopted the idea that you modify to solve a problem, not for any other reason, and we’ve kept it legal.

    Our next 4WD will have as little mods done to it as we can, and it sounds like you’ve gone that route with your Jimny.

    All the best

  8. I’ve often wondered how many 4×4’s on our roads are technically legal. I’d hazard a guess that the majority of those modified probably are not. Don’t get me wrong I think there’s some great ingenuity which has gone to waste with ADR compliance laws and it’s unfortunate. I now have a 2015 Suzuki Jimny. The only accessories are mud flaps fitted new on the showroom floor and it’ll stay that way for peace at mind.

  9. Hey Mike,

    I think you are correct, and have re-worded the missing words from the article

    Thanks, and take care

  10. The general rule is that the tray can be a maximum of 60% of the wheel base measurement. If you exceed this you end up with an illegal 4WD, and a much higher likelihood of bending something.

    Is that correct?

    I thought it was related to overhang past the rear axle center point, not the total length of the tray….

  11. Hi Ezydenias,

    It’s interesting to compare what is legal in one state here to another, let alone country to country. Some countries have almost no regulations, and others (like Australia and Germany by the sounds of it) have quite a few.

    All the best

  12. Ezydenias says:

    Is it just because I am from Germany or are those all actually just common sense? I am just asking, I hoped to find any puddles I might jump in once we move to Australia. But damn there was more shown you could do in Australia that is pretty illegal in Germany xd.

  13. Hey Ben,

    Interesting suggestion, and something I’ve not really thought much about, nor heard much about. I wonder how many that are chipped and tuned actually fail the emissions test?

    The DPF removal and EGR blocking is far more common, but you certainly raise an interesting point.

    All the best

  14. Ben Thomas says:

    One other item that should be added to this list is installing performance chips or tunes. These can significantly change the emissions characteristics of a vehicle.

  15. Hi Grant,

    Yep, lots of people sell the conversion kits. Like how the roof rack saga has been made very public lately, the figures and legalities should be made more obvious

    Take care

  16. NON compliant ADR accessories …… mate don’t worry if you shop at the supacentre for 4WD’s … they’re flogging illegal LED replacement headlight globes at the moment, that even state on the ad that they’re “not ADR compliant” but they can’t get enough of them mate !
    It’s all good, Charlie Vella doesn’t mind lining his pockets and bank account while at the cost of others police infringements ! And safety with the light pattern they throw out – well their photos on their site speak for themselves LOL
    I’m so sick and tired of seeing all these illegal 4×4’s getting around bringing a bad name to all those responsible 4×4 owners out there ! It’s that total lack of respect to the law and to other road users out of a self centre “all about me” attitude that makes me so very annoyed !! ??
    Keep up the good work mate

  17. Hi Karina,

    Don’t sweat it; its all pretty simple. You need to find out what is legal in your state, and go from there. If you are referring to 18 inch rims, 265/60/18’s are 775mm, and 275/65/18’s are 815mm. A difference of 39.5mm (to be exact), which is normally legal, providing you don’t lift the suspension at all.

    A good tyre shop will point you in the right direction.

    All the best

  18. I’m looking at purchasing a new D-max and I was interested to see that you mentioned tyre/rim combinations being an issue. I couldn’t find any other sources or information about this, but it makes sense if your tyres are inappropriate for your rims that it could be illegal. Do you happen to have any more details on legal tyre/rim combinations? I was looking at purchasing 275/65 tyres for the D-max which comes stock with 265/60 tyres so I’m suddenly sweating about this haha.

  19. Hey Warren,

    Nice work. It should all be fine.

    Enjoy your new vehicle!

  20. Warren Wilson says:

    Great tips.. just purchased a new Triton and already added a Safari snorkel, Kings laser LED lightbar, upgraded to proper Bridgestone A/T tyres (same dimensions as the H/T tyres the car came with) and roof rack.. fingers crossed all is compliant

  21. Hi Joanne,

    Yep, and lots of people have no idea. Glad I could help.

    All the best

  22. I have been shopping for a second hand 4wd recently and this article is extremely timely for me. It’s amazing how many of these illegal mods I have seen on vehicles for sale. Thank you for this advice!

  23. … Bigger tyres increase THE HEIGHT OF your centre of gravity…

  24. Hey Lois,

    Generally for temporary installations you are OK, but some states require certification. I would ring your local transport authority, and if you do go ahead make sure you keep all of the gear (and don’t cut seat belts etc) so you can put it back in, should the need arise in the future.

    All the best

  25. Lois Robey says:

    Would it be legal in the ACT to remove the 3rd row of seats in a 2020 Nissan Patrol Y62 and have a drawer set-up installed?

  26. Hey Ben,

    I’ve heard that argument too. If you service it properly (as in change the filters at the right intervals), it shouldn’t ever vent to atmosphere, so they should be compliant. No different to running your tyres until they are bald, in my opinion.

    That said, Mann and Hummel have actually changed the design on the new Provents, and they vent internally if the pressure builds up. You can convert the old style to a new type easily too, which I’ll be doing when mines due for a new filter. Western Filters should be able to help you out

    All the best

  27. Hi Aaron, awesome article, thanks for your insight!
    Question on the provent catch cans though… I’ve been told the pressure relief valve vents to atmosphere making them non compliant with ADRs?
    Any thoughts? The HPD website also claims that theirs is one of the few legal catch cans as they don’t vent to atmosphere…

  28. Hey Andy,

    Yep, no disagreements from me. Most 4WD’s need a substantial GVM upgrade to become useful, and then you risk breaking things. A truck is the way to go for sure.

    All the best

  29. Hi Aron good article. note your comments re the 200 series. A lot of money for very little carrying capacity.. I am always amused at these 70 series 2 diff machines. They are advertised as a 1 tonne ute but that is a 1 tonne cab n chassis. Add a tray body, 2 full fuel tanks and 2 occupants n there is not much left for payload.. Once again a shit load of dollars to carry a couple of hundred kilos if you are lucky. I see these dual cab v8 Utes with whopping great full wing bodies on them, hood racks, 2 spare wheels dual batteries bullbar scrub rails n rear bar kings roll out awnings, big black wheels n tractor tyres and the list goes on.. I would think that there would be no spare legal carrying capacity left for not even a 6 pack n loaf of bread…! 2007 I did the suns: current model 70 ser cruiser w turbo 6. 300 kg pay load. RRP on road $69k. Isuzu NPR 400 truck, 3600 kg payload on road $70k. My ap6 valiant wagon will carry more than 300kg…! And did for many years doing NT WA station work..!

  30. Hey Declan,

    Yep, there are heaps of little things like that which would be interesting to know. I guess that the chances of it causing an accident would be slim to none, but it still might not be legal.

    All the best

  31. Great read. It would be good to know the laws around custom turbo manifolds as it is a tricky thing to find out about.

  32. Hey Don,

    Thanks for the comment. I’m glad it was useful.

    All the best on your adventures!

  33. Hi Aaron. I take my hat off to you. I think you are way smarter than the average ‘Brown Bear!’
    At age 79, I have just bought my first 4WD – an 80 series, to
    tow a caravan. (Which we haven’t bought yet.)
    I have read and made notes on every one of your ’32 ways’ etc, and intend to do it right from the get-go. I learned a heap from you today, and rest assured, it will all be put to good use. Thank you for your insightful article.
    PS The future looks good!

  34. Hey Troy,

    No worries at all. All the best with your new vehicle


  35. Another quick thanks for the article! Been about 10 years and a different territory of Australia since I had to worry about all thing 4WD, but after taking possession of our new Ford Everest Titanium, I’m definitely not keen to loose out on such a large investment.
    Cheers, keep up the great work,

  36. Hey Ross,

    Cheers for the comment mate. You are correct; it is all too easy to be over the payload.

    You are correct also regarding the seat belts too; something that few people know about, and those that do tend to pass a blind eye. I’ve not heard of anyone being fined for it, and to be honest find it a bit daft. If your vehicle weighs under the limits at the time of being pulled over, I don’t agree with them saying its not legal as you should have accounted for available seat belts.

    It’s like saying you can’t tow a trailer that has the potential to be heavier than your tow capacity. Providing you don’t exceed your towing capacity (as in the actual trailer weight is under it), what leg do they have to stand on? You certainly aren’t over weight.

    It also makes you wonder about a vehicle like the 200 series. 600kg odd payload, and 8 seater. 8 by 72 is 576kg. Does that mean they are ‘over weight’ with a few heavier than average people inside and a full tank of fuel?

    No wonder people get confused about these things!

    All the best

  37. Hey great article. I have A gvm upgrade on my 2016 dmax as well. It was actually done to keep me legal when doing trips. As it turned out to be super easy to go above payload.
    A point I found out was that the number of seatbelts in the vehicle must always be added onto your payload criteria even if your travelling solo or with one other person. The inspectors actually consider the available seating when checking the vehicle for weight. You may be under payload when you set out.
    Then find someone broken down. 3 spare seats means 3 extra bodies in the car. In W.A that’s 72 kilo’s per seat average. If I remember correctly. It’s an easy thing to overlook. Not something I realised. Till I asked an inspector at an inspection stop in muchea about weights on the vehicle.
    Great article well done.

  38. Hey Pat,

    Really sorry to hear of the fire. Absolutely devastating. Good to hear everyone was OK, and you are looking at the bright side!

    Auto electrics can be done by a lot of people, but there aren’t too many who can do a really good job at it. It’s certainly not something you want to do a poor quality job on.

    Best of luck with the new vehicle, and thanks for the comments. I’m glad you’ve found it useful

    Take care

  39. Hi Aaron

    Your articles are really helpful.

    I now have a new 2019 Dmax after my 2015 Dmax caught fire and was completely destroyed.

    The cause of the fire was probably a very dodgy job with the installation of an after-market battery for running the accessories. Whilst that installation was done at an authorised Isuzu Dealership, and completed before I had even taken possession of the car, Isuzu Australia fell over themselves in their haste to deny any responsibility.

    I lost a fair whack of cash replacing the car but I learnt heaps from that experience.

    I’m now super careful as to what I have installed, where its installed and who installs it.

    This article has some excellent information and your comment that “after market gear is always the first to give you grief” is, in my experience, absolutely spot on.



  40. Hey Michael,

    Good to hear mate. Modify to suit your needs, but watch the bounds of the law too!

    All the best

  41. With a brand new second hand Hilux in the garage and some mods on the cards, this was a very handy and timely read. Cheers.