Replacement of tyres that change tyre overall diameter by more than 7% of the overall original diameter*.
* ’overall original diameter’ means the maximum outside diameter of the largest tyre specified by the vehicle’s original manufacturer as an option for the vehicle, as shown on the vehicle’s tyre placard.
Example requiring certification:
• Replacing 215/65R17 (712 mm overall diameter) tyres with 265/65R17 (776 mm overall diameter) tyres, an increase in overall diameter of 64 mm, or 8%.
Example not requiring certification:
• Replacing 215/65R17 (712 mm overall diameter) tyres with 235/65R17 (738 mm overall diameter) tyres, an increase in overall diameter of 26 mm, or 4%.
Tip: To determine if the tyres you have selected require certification you need to look at the tyre placard fitted to the vehicle by the manufacturer. Sometimes the tyre placard will show more than one tyre size, allowing optional tyres of that size to be fitted. If one of the tyre sizes marked on the placard (eg 215/65R17) matches the marking on the tyre sidewalls, certification is not required.