Vehicle design rules Victoria

For a 'definitive answer' I suggest you contact the relevant authorities who will provide you with specifics.
In Victoria contact VicRoads and Victoria Police. One is the registering authority who will oversee and approve vehicle modifications. Vic Police have the responsibility of enforcing the relevant rules. e.g. roadworthiness and legality of vehicles consistent with legislation.

I'm not aware of any state that has actually ratified the national standard yet...

The National Standard allows 4wds to increase thier tyre diameter by 50mm as opposed to 15mm at the moment (for NSW - I think Vic is the same)

I have an engineering certificate so taht I can run larger tyres on my Prado & still get insurance & rego!

Also the new tyres need to equal or exceed the placards load rating, however the speed rating can be lower....
For my research, 110km/h for Vic & 140km/h for NSW - please confirm this yourself.

Your speedo may not underread your true speed either.....& your new tyre may not touch any suspension components or bodywork in any possible situation..

Other than that & if you do a moderate amount of off road driving, the extra clearance is handy to match some of the bigger cars.

Cheers

in vic its 15mm not 5%
cheers

All,
The document you refer to is the:
National Code of Practice for Light Vehicle Construction and Modification dated 3 Feb 06.

The preface of the document says that the code has been endosed by all states and territories.
It is adopted in the ACT.

A quick call to VICROADS Transport Safety 1300 360 745 finds that Victoria is still in the process of adopting the code and have accepted it in part, so the victorians will need to ask specific questions of VICROADS till the code is adopted in full.
Cheers
Trevor

Von Helga,
Many thanks I can now review the document so I undestand it a bit more before taking action.

I am just a little paranoid about not being covered