[NC] Legal Wheels & Tyres

Wheels, Suspension, Brakes & Tyres questions and answers

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kris
Fast Driver
Posts: 310
Joined: Tue Jul 13, 2010 10:26 pm
Vehicle: NC
Location: Northern Sydney

[NC] Legal Wheels & Tyres

Postby kris » Sun Sep 26, 2010 2:28 pm

Hi All,
I'm currently looking at replacing my run flats on my NC with some new rubber and at the same time changing the wheels.
I've been given different advice but no confirmations that certain wheels and tyres are and are not street legal in NSW. Such as the inside edge of a tyre has to be a certain distance from its counter part on the other side of the car and wheels can only be +12mm wider than the largest recommended stock wheel size.
Can anyone please confirm (NRMA, RTA and my local mazda dealership weren't 100%) if 17x9 wheels or what options on my car would be street legal? Also, are tyres that are bought in the US with department of transport markings street legal in NSW? For instance the AD07/8, RE-11s, D Star Spec etc.
Cheers,
Kris

project.r.racing
Speed Racer
Posts: 3722
Joined: Sun Jan 18, 2009 10:16 pm
Vehicle: Non MX-5
Location: Glasshouse Mountains, QLD

Re: [NC] Legal Wheels & Tyres

Postby project.r.racing » Sun Sep 26, 2010 4:31 pm

+/-15mm tyre rolling diameter

+26mm wider than widest option available.

+39mm wider is car is under 1200kg (w/ engineers cert.)
+51mm wider if car is over 1200kg (w/ engineer cert.)

you'd have to comfirm the last 2, as i am only going from memory, the RTA does have it on their website.

project.r.racing
Speed Racer
Posts: 3722
Joined: Sun Jan 18, 2009 10:16 pm
Vehicle: Non MX-5
Location: Glasshouse Mountains, QLD

Re: [NC] Legal Wheels & Tyres

Postby project.r.racing » Sun Sep 26, 2010 4:35 pm


kris
Fast Driver
Posts: 310
Joined: Tue Jul 13, 2010 10:26 pm
Vehicle: NC
Location: Northern Sydney

Re: [NC] Legal Wheels & Tyres

Postby kris » Mon Sep 27, 2010 3:14 pm

Thankyou for the help project.r.racing.

I've also confirmed that the stock wheel is 7 inches in width (not written anywhere as far as i can see on the car or in the manuals) , the RTA will allow an 8 inch wheel without engineering certificate or a 8.5 inch width wheel with an engineering certificate. This means 9 inch is clearly out of the question, in fact what planet was i on lol?

Also cleared up the confusion with US tyres, that is as long as they meet the speed / load etc requirements of the car then they are perfectly legal.

Finally, does anyone know what an engineering certificate for a 8.5 inch width wheel with an appropriate tyre is expected to set me back, and can anyone recommend an engineering signatory in NSW?

Cheers

project.r.racing
Speed Racer
Posts: 3722
Joined: Sun Jan 18, 2009 10:16 pm
Vehicle: Non MX-5
Location: Glasshouse Mountains, QLD

Re: [NC] Legal Wheels & Tyres

Postby project.r.racing » Mon Sep 27, 2010 7:25 pm

kris wrote:Thankyou for the help project.r.racing.

I've also confirmed that the stock wheel is 7 inches in width (not written anywhere as far as i can see on the car or in the manuals)
it should be on your tyre placard. under bonnet or inside door gaps.


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