4WD Modifications and the Legalities Involved

Aaron Schubert Avatar
Aaron Schubert
Lives and breathes the outdoors
29 August, 2017
4WD Modifications and the Legalities Involved

4wd Modifications

These days, we are spoilt for choice when it comes to modifying a 4WD. Whether you want something custom, or an off the shelf item, you have more options than ever before. However, many accessories available can make your 4WD illegal so it’s important to shop smart and do your research.

You can walk into most 4WD shops and order yourself a 5 inch lift kit, have it installed and drive away with no questions asked. Your 4WD would be completely illegal and you may be none the wiser, until the local policeman pulls you up. There is a huge lack of knowledge around 4WD modifications and people are being caught out unaware.

It’s a shame that shops can install illegal gear on your 4WD. Not all will however; some will let you know, some will even refuse to do it. The advice provided here is based on my own experiences modifying my personal 4WD in WA.

I recommend that you refer to the guidelines as set out by your state.

QLD |  NSW |  SA |  ACT |  WA |  VIC

4WD Modifications and the Legalities Involved

What changes can make my 4WD illegal?

If you’ve changed your tyre size, suspension height or wheel track, your vehicle could be deemed illegal; it’s worth taking the time to make sure it’s within the boundaries as soon as possible.


If you need help with services on your vehicle, get in contact with your local Bridgestone Dealer.


Tyre size regulations

Every 4WD comes with a standard set of tyres, as designed by the manufacturer. You’ll usually find the placard on the inside of the driver’s door. You can fit larger tyres than what is on the placard, but it must be within the local regulations. In WA, a 50mm bigger diameter tyre is as much of an increase as you will get without going down the path of engineering.


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Lift kits

Body lifts and suspension lifts are also limited in height, varying from state to state. In WA, you can only lift the roof of your vehicle 50mm total, in combination of suspension lift, body lift and tyres. Effectively, you are limited to a 50mm bigger tyre and 25mm suspension lift without engineering. How many 4WDs do you think exceed that?

If you are looking for a lift kit, contact your local Bridgestone store who will be able to assist with all your requirements.


Wheel track

There are limitations to what you can do to your wheel track too. Although a set of 50”wheels and a big, wide tyre might look good, it may not be legal. Wheel spacers are illegal for on road use, so stay clear of them.

4WD Modifications and the Legalities Involved

What’s so important about having a legal 4WD?

If you think that being pulled over by the police and given a hard time is as serious as it gets, you’d be wrong; the consequences can be much more serious than that.


Complete vehicle inspections

If you are pulled over by the police, often they will make you get a full vehicle inspection. In WA, they will put a yellow sticker on your windscreen, which gives you a specified time frame to have your vehicle run over the roadworthy pits and passed, or you can’t drive it on the road anymore.

Pit inspections are often a real pain, as they will look at every single aspect of your 4WD to ensure it is 100% good to go, and not just the reason you may have been pulled up for in the first place. Oil leaks, further modifications that aren’t legal and any other damage can result in multiple trips to the pits to get your car re-certified, with costly repairs or changes in between.


Insurance claim payout reductions or denials

This is one of the more serious problems with driving a vehicle that is not roadworthy. If you take a look at your insurance policy, every PDS worth its salt (Policy disclosure statement) clearly says that you must notify the insurance company of any non-standard modifications, and that you must be driving a roadworthy vehicle.

If you have an accident with a vehicle that is not roadworthy, the first thing the insurance company is going to do is question it. Many people have been left high and dry by insurance companies who walk away from claims.

4WD Modifications and the Legalities Involved

Unsafe vehicle

Beyond all this, the laws that limit tyre size, wheel track modifications and suspension lifts are put in place to ensure people drive safe, roadworthy vehicles. You have a responsibility to drive a vehicle that is safe and roadworthy on the road. Some modifications, especially when not done correctly have a severe effect on your vehicles ability to brake, steer and handle safely. Is it worth putting your passengers and those around you at risk for the sake of a couple of modifications?


Contact your local authority

If you are unsure of whether your 4WD is legal or not, give your local transport department a call, and find out. Don’t rely on information you’ve heard from others, or read online; so much of it is not correct, and it’s not something you want to mess up.


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These days, we are spoilt for choice when it comes to modifying a 4WD. However, many accessories available can make your 4WD illegal.
Aaron Schubert Avatar
As an avid 4WD owner and photographer, Aaron Schubert lives and breathes the outdoors. When he’s not out exploring Australia by 4WD, he’s writing about it. Aaron runs 4WDing Australia, a blog dedicated to inspiring others to travel Australia by 4WD.

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Vehicle data is provided by DriveRight, tyre sizes are a guide only. Tyre sizes can vary, even on similar vehicles.
We recommend you inspect and check your tyre size. Learn how here. 

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