The DEFINITIVE legal issue(s) regarding wheels/tyres sizes

Hi All,
 
I have scoured the Forum posts but can find no DEFINITIVE answer for the ADR/legal position in increased wheel sizes, and what is and what is NOT legal.  There is a lot of hearsay floating around about the following issues, which I think should be rectified, the answers sourced from our shared knowledge base and posted as a sticky perhaps??
I've heard conflicting stories based around the following statements:

1. Legality of any MODIFIED wheel/tyre set up is driven by a straight comparison of stock wheel/tyre combo rolling diameter;
2. Legality of any MODIFIED wheel/tyre set up is driven by a limiting percentage increase of stock wheel/tyre combo rolling diameter;
3. Legality is driven by the wheel size ONLY, whereby an increase of up to 1" in wheel size is allowed;
4. As per point 3, but a 2" increase in size is allowed;
5. Track widths must not be increased by over 1";
6. Track widths must not be increased by over 2";

And other variations on the theme.  Obviously there can be no scrubbing or fouling of any modified wheel set up.
 
My original 1990 SW20 car had 17 x 8 ET+38 fronts on 215/40 and 17 x 9 ET+35 rears on 235/40 which filled the arches very nicely, though they are now swamped by the widebody bodywork.  Notwithstanding bodywork issues, the car is now rolling on the old wheels, which look daft, but are for all intents and purposes "legal" under some interpretations, though not so if you read some of the above points.
 
Standard 1990 SW20 tyres/rims were as follows:

 
Really need tsome clarity on this issue - if anyone can shed their knowledge and additional light on the subject I for one would be most grateful - it would also serve as an excellent "sticky" resource for our community.. Hoping someone can clarify this shortly
 
 
 
 

what he said, unless someone works for the DPI in WA here and has the relevant knowledge, your best bet is to go to their website and search, call, or find a registered engineer that deals with mods/compliancing certificates.

Have a look here, heaps of info:
http://www.transport.wa.gov.au/licensing/20500.asp
 
I have seen a page previously on either the tranport or infrastructure website previously (but cant find it now), that stated allowable maximums for increase in wheel diameter, wheel width, track and overall diamaters.
 
Best to call them.

I'm certain that an increase of track by any amount is not legal. Rim diameter can increase 2" wider than factory and rim width is anything as long as it stays within the guards as protruding outside is illegal. With rim diameter increasing, a lower profile tyre is needed to keep the overall wheel diameter within +/-5mm of factory rolling diameter.
That's how I understand it anyway.

he has to take it over the pits for registration, so yes they will notice 19in rear rims even tho it looks "good" it'll stand out like dogs balls that they're over size etc. esp with the body kit.
 
14in rims with thick mickey tompsons would look o'right.......

jdmr288

I'm certain that an increase of track by any amount is not legal. Rim diameter can increase 2" wider than factory and rim width is anything as long as it stays within the guards as protruding outside is illegal. With rim diameter increasing, a lower profile tyre is needed to keep the overall wheel diameter within +/-5mm of factory rolling diameter.
That's how I understand it anyway.

 
This sounds like how it was explained to me.
You can have whatever size in diameter you please, as long as the overall diameter is within  +/-5mm of factory rolling diameter.
Thats NSW anyway, but its easy for joe plod to say "2" over, thats a defect notice for you"
The explanation for tyre width sounds right too,
 

I think they go off the wheel/tyre placard for the car.  I believe the local cars have specific placards for each model (exec/SS) etc, but on some older BMWs (E46) I have seen placards that list all the wheel sizes for all varients.
 
SW20 wheels only went from 14 to 15 inch.
 
I wonder if the rules have changed recently, as I cant find that info on the government website on the wheel/tyre allowances that I read a while back.
 
Cheers

You mean the one with the adjustable wing that had the skinnier 5 spokes (like Mandalays car)?  Quite sure those were also 15s, or is there another rev after this one?