Wheels and tyres
Since 1973 all cars are fitted with a tyre placard (usually fitted in the glove box, the engine bay or on a door pillar).
This specifies the wheel and tyre combinations recommended by the vehicle manufacturer. This placard also specifies load capacity, speed rating and the recommended tyre air pressure.
Replacement wheels and tyres
Replacement wheels and tyres may be fitted provided that they comply with the following requirements:
- Ensure that the replacement wheels have been designed for the vehicle's hub and have the same bolt or stud spacing as the original and the same centre location method.
- Ensure the offset of the rim is not reduced by more than 13 mm from the original rim.
- The wheel track must not be increased by more than 26 mm beyond the maximum specified by the vehicle manufacturer. Maximum allowable track measurements for individual vehicle models can be obtained from the Department of Planning, Transport and Infrastructure.
- Spacers are not permitted between the hub and wheel unless originally fitted by the vehicle manufacturer.
- Rims that have been widened by inserting a spacer band are not permitted.
- Rims must have no more than one circumferential weld.
- Welding must be carried out in accordance with recognised engineering standards, and the rims must comply in all respects with specifications contained in the Tyre and Rim Association of Australia - Standards Manual.
- The wheels and tyres must not foul the body, suspension or any part of the vehicle under any operating conditions and must not project beyond the bodywork when the wheels are in the straight ahead position and viewed from above.
- If the wheels of a vehicle are retained by multiple nuts or set screws, not by splines and a single nut, then the wheel nuts must match the tapered holes in the wheel and the nuts must be engaged for their full depth of thread.
- Wheel rims fitted to passenger cars manufactured after 1 July 1985, which are not original equipment or an original equipment replacement by the vehicle manufacturer, must be indelibly marked with the wheel's nominal diameter, width and offset and with identification of the manufacturer of the wheel and the standard to which the wheel was manufactured.
- The use of composite wheels (two or three piece) is permitted if they are manufactured and marked in accordance with the standards described above and fitted to vehicles manufactured on or after 1 July 1985.
- Modifications to disc brake calipers, hubs and suspension and steering components to enable the fitting of replacement wheels is not allowed without a certificate from a MR426 Chartered Professional Engineers .
The fitting of aftermarket wheels to your vehicle may result in the vehicle's wheel track being altered.
The wheel track is the distance measured across an axle from the centre line of the tyre tread to the centre line of the other tyre on the opposite tyre tread.
The Passenger Car Track List for 1970 and later vehicles specify the maximum allowable wheel track for light passenger vehicles.
The overall diameter of a wheel and tyre fitted to a vehicle must not be more than 15 mm greater than the largest tyre size listed on the tyre placard and not more than 15 mm less than the smallest tyre size listed on the placard.
Specifications for overall tyre diameters are listed in the Tyre and Rim Association of Australia - Standards Manual. Note: If tyres are to be fitted with a diameter outside of this requirement then an MR620 Application to Modify a Motor Vehicle and a report from a MR426 Chartered Professional Engineer is required.
The following requirements must also be met:
- The tyres fitted must be suitable for the rim. The tyre retailer should have information about matching tyres and rims. Specifications for overall tyre diameters are listed in the Tyre and Rim Association of Australia - Standards Manual.
- The tyres must be free of any apparent defect that could make them unsafe.
- The replacement tyres must have a load capacity not less than the lowest load rating specified on the tyre placard.
- The speed rating of the tyres fitted to vehicles for off-road must be of at least 140 km/h ('N') when the tyre placard requires a higher speed rating than 'N'.
- The speed rating of the tyres fitted to a passenger vehicle must be at least 180 km/h ('S') when the tyre placard requires a higher speed rating than 'S', for all other vehicles a speed rating of at least 120 km/h applies ('L').
- Tyres fitted to an axle of a vehicle must be of the same size and carcass construction.
- Tyres fitted to vehicles manufactured after 1972 must be made of the same carcass construction - eg radial, crossply.
- Tyres fitted to passenger cars may not be treated by recutting or re-grooving of the tread unless the tyre is constructed to do so and marked as such.
- Tyres fitted to a vehicle, which do not have tyre wear indicators, must have a tread pattern at least 1.5mm deep on all parts of the tyre that normally come into contact with the road surface. If the tread has worn down to any of the tyre wear indicators, or there is less than 1.5mm of tread depth on the tyre, the tyre is then considered to be unroadworthy.