Wheels and tyres are vital to your safety. Since 1971, strict design standards (ADR 24) have been progressively introduced to specify wheel rims that will stop a deflated tyre from coming off the wheel, to specify strength, air pressures, speed ratings and allowable combinations of wheel and tyre sizes.
From 1973 all cars have been fitted with a tyre placard (usually located inside the driver's door, glove box of fuel filler cap) which specifies the wheel and tyre combinations recommended by the vehicle manufacturer. The placard also specifies recommended air pressure, load capacity and speed rating of tyres.
Every passenger car manufactured after 1972 (ADR 24) is fitted with a tyre placard containing information on original and optional tyres and rims for that vechicle model.
A motor vehicle under 4.5 tonnes, which is required to comply to ADR 24, may be equipped with tyres often than those listed on the tyre placard provided that:
- the load rating of the tyres is not less than the lowest load rating listed on the tyre placard on the vehicle or equivalent variant of that model vechicle;
- the speed rating of the tyres fitted to a passenger vehicle is at least 180 km/h (''S') when the tyre placard requires a higher speed rating than "S",
- the speed rating of the tyres fitted to vehicles with special features for off-road use of at least 140km/h ("N") when the tyre placard requires a higher speed rating that "N", and;
- for all other vehicles a speed rating of at least 120km/h
In special circumstances, the speed rating may be less than the ratings specified above if the speed rating of the tyre is more than the vehicle's maximum speed.
Where a vehicle has its GVM re-lated, the tyre load capacity must be capable of carrying the revised GVM, both in total and across individual axles.
Replacement tyres must also conform with the following requirements;
- the tyres are rated by the tyre manufacturer as being suitable for road use,
- the tyre construction (e.g. radial) and size must be the same on each axle; and
- where retreaded tyres are used, they must have been retreaded and marked in accordance with the provisions of Australian Standard AS 1973 - 1993 Pneumatic Tyres - Passenger Car, Light Truck and Truck/Bus - Retreading and Repair Processes.