Light vehicle modifications
A guide to modifications requiring certification under the Vehicle Safety
Compliance Certification Scheme
Purpose
This Vehicle Standards Information (VSI) No. 6 is intended to help vehicle owners and
modifiers determine what modifications to vehicles up to and including 4.5 tonnes gross
vehicle mass require certification.
http://www.rms.nsw.gov.au/registration/downloads/vsi/vsi6.pdfSUSPENSION
Item Modification
12 Altering vehicle ride height by more than one third of the manufacturer’s suspension
travel in the direction of the ride height change.
Examples requiring certification:
• Conversion from coil to leaf springs.
• Any modification to the suspension configuration.
• Fitting a suspension of a different design eg from a different make and model
(eg from coil springs to leaf springs).
• Fabrication of suspension mounting points.
Examples not requiring certification:
• Modification of suspension with components or parts which meet or exceed the
original vehicle manufacturer’s specifications.
• Fitting uprated roll (sway) bars, shock absorbers, springs, struts or manufacturer’s
options for that particular year make and mode
WHEELS AND TYRES
Item Modification
13 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.
FUEL SYSTEM (continued)
Item Modification
48 Fitting/adding an alternative fuel tank or repositioning an existing fuel tank to non-original
mounting points.
Example requiring certification:
• Fitting an alternative fuel tank or repositioning of an existing fuel tank to
non-original mounting points.
Example not requiring certification:
• Fitting a replacement fuel tank of equal capacity using the original manufacturer’s
mounting points.
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