4WD Internet Magazine
The world's premier 4WD magazine since 1995
Click here to return to the 4WD homepageIndex of 4WD vehicles and manufacturersThe Four Wheen Drive Picture Gallery4WDOnline.com ClassifiedsThe 4WD Online Clubs Database is a user-driven collection of clubs around the world4WD Online Links DatabaseHave your say on the Auto ForumsChat with others who have an interest in 4WDEnquiries and Contributions for 4WDonline.com

Modifications and Vehicle Standards (FAQ)

2000: Scott Brinckman of Queensland writes in:
scottish a netspace net au -->
After many phone calls to Queensland Transport (these rules are supposed to be National) and obtaining the modification hand book, I quote "The suspension travel in the bump or rebound mode must not be altered by more than one-third of that specified by the manufacturer".
Now, Toyota do not have such a measurement(?); again after many phone calls, I got a very helpful QLD Transport officer, and he said "fully compress the suspension ,then lift the car to let the suspension fully drop. Measure the distance between and then you have got your bump and rebound mode."
Having done so, I very legally raised my 80 series suspension by 4". Further more, you can then add body lift blocks to a height of no more than 50mm or 2" for even greater ground clearance (but you have to put it over the pits for a body lift modification).

Something that the above emphasises is that it is important to contact your local road traffic authorities before carrying out any modification; they are usually very helpful. Victoria (at least) now has a short list of engineers to which they direct all those modifying vehicles for approval. These guys are very effective and reasonable - both by experience and by report - 4wd.sofcom.com/4WD.html

1995: Federal Government makes the laws governing vehicle standards but the state authorities, `Vic Roads' in the case of Victoria, issue various guidelines interpreting the standards. Regulation 801 requires that one must not modify a vehicle `except with the approval of, or in accordance with guidelines issued by Vic Roads'. Some common modifications have been explicitly approved and notices are available covering them. Many modifications also require an `Engineers Report' to be submitted by `an appropriately qualified engineer'.

The general principle seems to be that a vehicle must be "at least as good" as when originally built, in terms of safety, emission control and so on. If the vehicle is substantially modified, this principle must still apply.

Crash-repairs carried out by qualified repairers in accordance with current trades practices are not covered here.

Lowering or Raising Vehicles.

The limit on the amount by which a vehicle can be raised or lowered (a 4x4 is more likely to be raised than to be lowered) is that the clearance between the suspension bump-stops cannot be `altered by more than 1/3 of that specified by the manufacturer'. In addition, coil springs may not be cut.

(Exactly how would this apply to the height-adjustable Range Rover?)

Wheels and Tyres.

There are limits to big wheels and tyres. The largest allowed rim increase is 25mm (1") larger than the widest wheel that the manufacturer offers for the vehicle. Tyres must be appropriate to the rims and the load and speed rating must equal or better the manufacturer's specifications.

This means that the owner of a fast and heavy 4WD, such as a Range Rover or a an 80-series Land-Cruiser, is much more limited in the choice of tyres than the owner of a more mundane vehicle.

The rim diameter can be increased by 50mm (2") but the overall tyre diameter cannot be increased by more than 15mm.

The track can be increased by up to 25mm, but not on cars with front-wheel drive and McPherson struts, nor with diagonally split brake systems.

Brakes, Steering and Suspension.

Authorities are understandably reluctant to allow tampering with steering and brakes:

An engineer's report is required for any modifications to the braking system, however other evidence may be acceptable if this involves converting to another system optionally supplied for that vehicle and model by the manufacturer - check first.

Steering and suspension components cannot be cut, welded or heated unless they are then inspected by X-ray and a comprehensive report is included.

Body and Chassis.

An engineer's report is needed for changes to the vehicle's frame or chassis, and if the vehicle was manufactured after 1972 a report is required for any change to the passenger compartment and panels forward of the fire-wall.

The chassis can be extended, but an engineer's report must cover any extension forward of the rear-most spring hanger and any modification to major suspension components.

Engine Conversions.

The regulations allow a replacement engine to be fitted if it is "similar" to the original. This includes an engine offered as an option by the manufacturer provided that other components, especially `structure, suspension and brakes', are upgraded to match.

A different engine of similar `power, weight and emission standards to that of the original engine' may also be fitted, but an engineer's report is needed for any modifications to supports or structure. The replacement engine must be of the same age as the vehicle or newer and must meet all emission standards applicable at the vehicle's date of manufacture

If a significantly different (ie. larger and more powerful) engine is to be fitted, an engineer's report must certify that the vehicle is still safe and satisfies the regulations for construction and emissions, and must also cover any effects on 'the drive-train, stability and traction'.

Bull Bars.

Fitting a bull bar to a vehicle is considered to be a modification. Any bull bar must be constructed and fitted so that it does not reduce the safety of the vehicle, interfere with driving it, or present an undue hazard to pedestrians and other road users. Sharp edges or protrusions are not allowed, and forward and side members must either be made of round tubing or the the outer edges must be rounded to a radius of 10mm or more.

ADR 69 covers Full Frontal Impact Occupant Protection [crash-testing of vehicles]. It applies to all new passenger cars (MA category) introduced after 1 July 1995 and to all passenger cars manufactured after 1 January 1969. It does not require an air-bag but fitting one is a popular way of satisfying ADR 69. Loosely, a bull-bar must not interfere with ADR 69 compliance. A bull bar must be

one certified by the vehicle manufacturer as suitable for that vehicle; or,

one which has been demonstrated by the bull bar manufacturer to not adversely affect compliance with ADR 69 or interfere with the critical air bag timing mechanism as the case may be.

Demonstration of compliance with ADR 69 requires full scale barrier testing and to demonstrate that the critical air bag timing mechanism is not affected would also require full scale barrier testing.

Older vehicles.

Owners of series-one Land-Rovers may like to hear that it is not necessary to have outside door-handles provided that the inside ones can be reached from outside at all times. They and some Jeep owners may be interested that it is also permissible to leave removable doors off, provided that seat belts are worn - although Vic Roads strongly recommend against removing the doors.

Older vehicles had to have a windscreen wiper on at least the driver's side. Vehicles manufactured after 1 January 1963 must have a windscreen wiper on both sides. After 1 January 1973 wipers must be power operated. (A SI-SII wiper motor would have to be working, as it presumably did when manufactured.)

Vehicles manufactured after 1 September 1966 must be fitted with turn-signal lamps. Most vehicles manufactured after 1 January 1973 must be fitted with turn-signal lamps that comply with ADR 6/00. Turn-signal lamps do not have to self-cancel, but if they originally did then Vic Roads "strongly" recommend that they still do so.

A rear window demister does not have to work.


If you are intending to import a vehicle, contact the Federal Office of Road Safety: Canberra (062) 747 483. It would be a good idea to contact `Customs' too.

Left-hand drive vehicles cannot be registered, although individual approval may be given for special-purpose vehicles. Some vehicles were originally registered as left-hand-drive however, before this ruling came into force - they are ok.

Vic Roads.

This article is based on material supplied by Vic Roads [10/95]. Hopefully it is correct but this cannot be guaranteed. You should contact
Vehicle Safety Branch,
60 Denmark St., Kew, Victoria 3010,
or the appropriate authority in your state, for more details and for the current regulations. It would also be wise to contact a vehicle engineer before starting any modifications. [-'95]

Go to the main conversion page

4WD Magazine
4WD Vehicles A-Z
4WD Gallery
4WD Conversions
Mechanical Info
Military Vehicles
Travelling Tales
4WD Toys & Models
History of 4WDs
Contact 4WDOnline

4WD Databases
Book Database
Gallery Database
Purchasing Database
Personal Homepage Database
Add | Modify

Automotive Sites
Hot Rods & Muscle Cars

Top border of the 4wdonline.com site