VSB14 - NATIONAL CODE OF PRACTICE for LIGHT VEHICLE CONSTRUCTION and MODIFICATION - SECTION LS
TYRES, RIMS, SUSPENSION AND STEERING
VERSION 2.1 NOVEMBER 2015
4.1 REPLACEMENT TYRES ON STANDARD (OR MANUFACTURER’S OPTIONAL) RIMS
A motor vehicle under 4.5 tonnes GVM which is required to comply with ADR 24 may be equipped with tyres other 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 of the vehicle or equivalent variant of that model vehicle;
- 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 140 km/h N when the tyre placard requires a higher speed rating than N; and
- for all other vehicles a speed rating of at least 120 km/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. This will need to be confirmed with the Registration Authority.
4.2.4 Overall Nominal Diameter
The overall diameter of any tyre fitted to a passenger car or passenger car derivative must not be more than 15mm larger or 26mm smaller than that of any tyre designated by the vehicle manufacturer for that model.
The overall diameter of any tyre fitted to:
- 4WD passenger vehicles specifically designed for off-road use (typically MC ADR category). All wheel drive (AWD) vehicles including those AWD vehicles that may be certified as MC ADR category, (also commonly known as soft roaders) are not included in this category;
- 4WD goods vehicles and their 2WD equivalents if the chassis and running gear are essentially the same as the 4WD version (N ADR category); or
- any medium weight goods vehicle (NA2, NB ADR category).
Must not be more than 50mm larger or 26mm smaller than that of any tyre designated by the vehicle manufacturer for that vehicle.
Note: Increases in tyre diameter are subject to compliance with all other requirements specified under this clause (Clause 4.2 Non-Standard Tyres and Rims) and may therefore be limited by other factors such as insufficient clearance.
Speedometer accuracy must be maintained for the selected tyre and rim combination to within the degree of accuracy specified in ADR 18 where applicable. It is suggested that the degree of accuracy is in accordance with the most recent version of ADR18.
4.2.5 Tyre Aspect Ratio
Because of the different handling characteristics, the aspect ratio of tyres fitted to the front axle must not vary by more than 10 from the aspect ratio of tyres fitted to the rear axle (e.g. 175 65R14 front and 205 45 R14 rear, has an aspect ratio difference of 20 and is not recommended, whereas 175 65 R14 front and 195 60 R14 rear has a difference of 5 and has similar handling characteristics).