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Is your 4WD legal?

4WD modifications

Is your 4WD legal?

It’s pretty common to see big 4WD’s driven daily on the road. Bigger tyres and lift kits will make a 4WD more capable off-road, but it also makes them illegal on the road, unless you have jumped through a number of hoops. A vehicle that is illegal has a number of very serious risks attached to the driver, which I will go into below.

What is legal?

For starters, let’s consider what is legal, and then you will know where you stand right now. In WA, VSB 14 has been adopted, which is a document that goes through the large majority of modifications done to vehicles, and what is legal or illegal.

If you have modified any of the following items on your 4WD it would be a very good idea to do some reading up:

  • Tyre size
  • Suspension
  • Wheel track
  • Brakes
  • Body
  • Chassis
  • A vehicle that could be over weight

Where can I find VSB 14?

If you want to read through the document, you can find it here.

For the purpose of this post, I will only touch on body/suspension lifts and tyre sizes.

4WD engineering approval

If you want this, you need engineering approval

Lifting your 4WD

In VSB 14, It states that your roof height may only be lifted by 2” (or 50mm) from the factory (or standard height) before it needs to go through a lane change test. This 50mm is the total combination of body lifts, suspension lifts and bigger tyres.

You are also not allowed to fit tyres that are more than 50mm bigger than the factory tyre diameter. For a lot of four wheel drives, 31’s are standard tyres, so 33’s are the biggest you can legally fit (or 285’s from 265’s).

In reality then, you are limited to:

1” lift and 2” bigger diameter tyres (together)

2” lift and the same size tyres.

For those of you out there that are running bigger than a 2” lift, your vehicle is illegal. If you have bigger tyres than standard and a 2 inch lift (or bigger), your vehicle is also illegal. The only way this does not apply is if it has been signed off by an engineer.

4x4 tyre legalities

There's no way these would be legal

Tyre sizes

Every 4WD should have a sticker which details the factory tyre size. Find the sticker (usually on your drivers door framework) and see what it says. If the tyres you are running are bigger than 50mm than the number stated, you have a problem.

What are the risks of driving an illegal 4WD?

A lot of people know their 4WD’s are illegal, and don’t seem to care. Just as many don’t know, but either way, you really, really need to care as the consequences of driving an illegal 4WD are extreme:

Insurance payouts

4WD owners across Australia use a variety of different 4WD insurance companies to make sure their pride and joy is covered should the unthinkable happen to it. The problem though, is that too many people are unaware of what the implications of having modifications to their vehicle can result in.

I hear people say all the time ‘My insurance company have insured my 4WD with a 3 inch lift and 35’s’, and they genuinely believe that their vehicle is insured. To be blunt, in the event of an accident, your insurance company can literally tear your policy up and walk away without paying a cent.

4WD insurance issues

If you have an accident with illegal mods, you could be in trouble

You see, you are required to tell your insurance company about any modifications done to the vehicle. More importantly, they all have fine print which specifically states that your 4WD must comply with the road regulations, and if it doesn’t, refusal of claims can occur.

I’ve spoken to insurance companies on the past, and told them of lift kits and bigger tyres on several vehicles, and they all say ‘Sure, no worries, I’ve added it to your list of modifications and you are covered’. However, the poor sales bloke (or lady) has no idea what is legal or not, and in the event of an accident, if your vehicle is outside of the regulations, you may have a claim refused.

Yellow stickers

The Police have a responsibility of pulling vehicles over that they deem to be un-roadworthy. They are inspected on the side of the road, and if the police believe the vehicle isn’t roadworthy, you may get a yellow sticker. This is a compliance notice which can only be removed by a qualified vehicle examiner once the vehicle is brought back to roadworthy standards. Yellow stickers can be issued for a huge range of things, from engine modifications that are not approved through to tyres sticking outside of the guards, oil leaks, cracked windscreens, perished seatbelts, big lift kits or bald tyres and the list goes on!

Getting a yellow sticker off your vehicle can be a pain, because even if the Police only pick one or two items that need attention, in order to pass the vehicle examination everything is scrutinized. It is better to play on the safe side and keep your vehicle looking good, to avoid the chance of getting pulled over and given a yellow sticker!

4WD handling issues

How do you think this would handle?

An unsafe vehicle

The entire point of having vehicle standards is to ensure that people drive safe vehicles on the road. At the end of the day, this is far more important than how far your 4WD goes off road.

By fitting larger tyres, your braking capacity is reduced. By fitting a lift kit, your center of gravity increases. By changing the wheel track of your vehicle the handling changes. All of these things (and many more) can contribute to having an unsafe vehicle. In order to cover yourself, get any modifications that are outside of the regulations engineered.


If my vehicle is illegal, is it definitely unsafe?

This is where things get a little interesting – just because you are running a lift kit and bigger tyres does not necessarily mean your vehicle is unsafe, providing the work has been done correctly with quality components. In many cases, a vehicle with 50mm tyres and a quality 2 inch lift kit will handle better on the road, but you still need to prove it is safe by having an engineer sign it off.

4WD vehicles offroad

Have a chat to a vehicle engineer

What can I do to make my 4WD legal?

If you know for sure that your vehicle is illegal (essentially if your roof height has gone up by more than 50mm from factory), you need to do a lane change test, and have an engineer to sign off on the modifications. You can find a list of engineers to speak to here. The only other solution is you reduce the modifications done to the vehicle so it complies without the need of engineering.

My thoughts

Now, I understand this post may get your blood boiling a bit, and I totally understand. My intention is merely to make those with 4WD’s aware of what you can and can’t do, and how those decisions can affect you in terms of your insurance, the way the police deal with you and what modifications can do to a 4WD.

If you have a 4WD that has a lot of gear on it, take a look at this post - What does your 4WD weigh? If it is over the manufacturers capacity, your vehicle is not legal. However, I do believe there is an unhealthy obsession with fitting Bigger Tyres and lift kits, without proper consideration as to the benefits and risks associated with doing so. Not every modification will make your 4WD more capable; there are a lot of Downsides to 4WD modifications that people don't think about.

Legal 80 series lift

My legally modified 80

That said, I think the laws surrounding modifications of 4WD's need to be seriously looked at, and I'm sure a number of you would agree. Let me know what you reckon below!

Comments on this entry are closed.

  • Bigkev

    Just to clarify tyre sizes, any car that is placarded with 265/70/16 tyres, most common size, cannot run a 33″ or 285/75/16 because this exceeds the 50mm difference. The 285 is actually 7mm too big. My request at DOTWA was rejected on this basis.

  • Hey mate,

    Thanks for the information. You’d think they wouldn’t worry too much, given that most tyre manufacturers vary their sizes anyway. I thought 265/75/16 was more common than 70/16?


  • Jackson Redstar

    In America, it is common for off road vehicles to see 4-6 inches of lift and 35-37 inch tires (usually on jeeps, not many twin solid axle vehicles left here) while saftey is important, the Aussie standards seem way over done

  • I totally agree; there are plenty of modified 4WD’s that handle better than they did from the factory showroom, but unfortunately there are serious risks of driving a 4WD that isn’t legal over here. I don’t see it changing any time soon!

  • Mickey

    An interesting write up. Luckily for us most of these very strict laws do not apply here in the nt, where we can go 100mm overall lift. But what I would like to know is if I have my 4wd set up within all nt laws and then travel interstate with 100mm over all lift, am I breaking the law. Would insurance still 100% no questions asked cover my nt regoed and compliant 4wd if I were in another state where VSB 14 has been adopted???

  • Hey mate,

    You’ve brought up a very interesting question. There are a heap of grey area’s when it comes to 4WD insurance, and you’ve highlighted one of them! In many cases, unless the assessor is very knowledgeable, or your vehicle is obviously unroadworthy, your claim will slide by with no problem at all.

    However, there’s always the slim chance that it doesn’t go through and you could be in for a world of pain. It’s hard to get this sort of information from insurance companies too, but perhaps it would be worth a go.

    I’d love to know if you get an answer!


  • Kieran Campbell

    I’m looking at lifting my Hilux and was just wondering if the roof height included any roof attachments, i.e awning, roof rack, gas bottle holder etc or i s it worked from the manufacturers standard roof height from their vehicle specifications?

  • Hey Kieran,

    It’s not worded very clearly, is it? It doesn’t consider any roof attachments; its just the factory roof height. I think they do this as its the only measurement that goes up with increased tyre size, suspension and body lifts


  • Michael Atkinson

    It’s not a huge difference between the two but the profile difference between 75% of the tread width and 70% can be enough of a difference to put your speedo out of whack too😉

  • Chris BSomething

    I think the tyre size thingy applies to the biggest tyres fitted to the model. So sometimes there’ll be another model that has a bigger tyre placard and you can use those numbers instead of the numbers on your placard. An example is 70 series Landcruiser. The skinny tyres fitted to the cheaper models are actually taller than the wider tyres fitted to the GXL. So you’re entitled to work your figures based on the taller tyres even if they weren’t original to your particular car.

  • Hey Chris,

    I’ve heard this too. It possibly is correct, but it’d be good to know for sure


  • Chris BSomething

    If you look at the modification rules on vicroads it talks about “specified by the vehicle manufacturer for that model or vehicle series”.

  • Hi Chris,

    Good to know. This post is referring to WA though.


  • Ian Reichelt

    Do you know of any engineers in SA that could sign off a 4 wheel drive?

  • Hey Ian,

    I don’t mate, but I’m told the guys at Regency should be able to give you a list. In WA you can find it online, but I cant see that for SA.

    Take care

  • Jacob Savell

    Hi guys i have a td42 gq coilcab with a 6” ligt and 35” tyres i keep getting yellowed and i keep spending $90 to get the sticker removed but is there a place in or around perth that dose engineering for that size lift and tyres ??? Cause theres no were in geraldton that is willing to do it cheers

  • Hey Jacob,

    I doubt you will get a vehicle with such a big lift engineered in WA, but you could try. Here’s the list of engineers, or try On Track Fabrication: