Was flicking through a government website and found this. Sure raises a few eye brows concerning the legality of some of the mods on 4X4's.
4WD VEHICLES
Tyres
The outside diameter of the wheel and tyre
combination must be no more than 15 millimetres
over the largest diameter wheel and tyre
combination as specified for the vehicle on the tyre
placard. Increasing tyre size
places further stress
on the vehicle’s
suspension, steering components
and braking systems. In order to have a larger
size wheel and tyre combination fitted to a vehicle
the owner must engage the
services of a qualified
engineer, who may be able to support the increase
in size.
The wheel and tyre combination must not foul on
the body, the
suspension or any other part of the
vehicle under any operating conditions. The wheel
and tyre combination must not project beyond the
bodywork when the wheels are in the straight ahead
position and when viewed from above.
Rims
Regulations which
came into effect
on the 3rd September
2009 permit persons to
fi t any rim size, provided
that the overall wheel
size (including tyre) does not increase by more than
15 millimetres over the largest tyre size listed on the
vehicle’s tyre placard.
Refer to Australian Design Rule 42 and Regulation
26 of the Road Traffic (Miscellaneous) Regulations
for further clarification.
Suspension
Any
suspension lift over 50 mm (2 inches) in South
Australia requires the following:
• the approval (in report form) from a chartered
professional engineer
• a lane change manoeuvre
test procedure carried
out by a chartered professional engineer
• an application to modify a motor vehicle lodged
with the Department of Energy, Transport and
Infrastructure (DTEI).
• an inspection by a Vehicle Inspection Station
mechanic.
Raising a 4WD is not recommended due to the
cornering instability that may result. Often cars
are raised because the owner wants to fit larger
wheels and tyres that would otherwise contact the
mudguards. In these cases the wheels and tyres
may themselves be illegal.
Engine Management System
The engine management system (computer)
of modern vehicles is an integral part of the
emission control system. Re-calibrating the engine
management system by changing the chip or reprogramming
or replacing the unit with an after
market computer, may result in non-compliance with
the emission control Australian Design Rule (ADR)
applicable to the vehicle.
Turbo timers are not to be fitted to vehicles
manufactured on or after 1 January 1972. Australian
Design Rule 25 requires that the normal function of
the engine only occurs when the ignition is in the
‘on’ position.
Any alteration to the manufacturer’s boost pressure
and/or the induction system, including blow off
valves, to passenger vehicles manufactured on or
after 1 July 1976 will not be granted approval, as
compliance with emission control ADR’s cannot be
ensured.
You can view the Australian Design Rules on the
Internet:
http://www.infrastructure.gov.au/roads/motor/
design/index.aspx
Protrusions
A protrusion is any object or fitting, not technically
essential to the vehicle, which protrudes from any
part of the vehicle so that it is likely to increase the
risk of bodily injury to any person.
Any object fitted to a vehicle must be designed, built
and fitted to the vehicle in a way that minimises the
risk of injury. This means fishing rod holders, spot
light/s (depending on placement), aerials etc., may
be illegal if they are likely to cause bodily injury in
the event of a collision. See Vehicle Standards 30
and Australian Design Rule 42/00.
Pay Load Weights
The majority of 4WD’s on the Australian market have
a pay load capacity of around 600 kg. When loading
your 4WD you need to take into consideration
what extra items you have added to your vehicle.
Additional items such as bull bars,
winches and long
range fuel tanks affect a vehicle’s pay load.
When taking into consideration a vehicle’s pay load,
the owner needs to know the ‘tare weight’ and the
‘gross vehicle mass’. Once these items are known
then the vehicle’s pay load weight can be worked
out. Overloading a vehicle is a serious road safety
risk and can sometimes void vehicle warranty.