St185 Legal Rim Size

[ST185GT4]

Hi Guys (great to be here),

I'll get straight to it.Have been searchin an readin at this is how I understand it.....

Vicroads Vehicle Standards Info no.8 says;

The overall diameter must not be 15mm greater than the largest diameter tyre specified by the vehicle manufacturer for that model or vehicle series.

Theres a tyre and rims standard of Australia manual that provides this info.

(I'm assuming it'll be something like max std. 205 60 R16 if optional sizes are allowed and that was it's size)

Does anyone know what this tyre and rim info is....or simply.....

What's the legal max tyre and rim for my st185 gt4 in Victoria and would that change if it's an import?

I have gratefully read the threads on SA Legal and stuff and assume from them that its the same for all states so I hope this helps toymods newbies like me.

Note: Overall tyre diameter can be calculated and compared on one the the online calc's in the "SA Legal Height/Rim changes?" forum.
(It's a mystery to me how its actually calculated, so any help on that would be much appreciated.)

[CrUZida]

There are no legal limits for RIM sizes.
There are only legal limits for TYRE sizes.

The rolling diameter (aka height) must be within -10mm to +15mm of a stock size (remembering that most cars come with 2 different tyres depending on what model you get, so you can use this to your advantage).
And the width must not be more than 30% wider than the widest tyre for that car.
Obviously the speed/load ratings of tyres must be legal for your car too.

Now what tyre size you chose limits what width rims you can use.
A rim MUST NOT be wider than the tyre.

For instance a 205 tyre is 8.1", so an 8" rim is your legal limit.


Calculating rolling diameter is easy. But you need a calculator or excel.

eg. a 205/60/16
205mm wide, 60% profile height, 15" rim.
Tyre height is
2 x 205 x 60% (2x205x0.6) = 246mm
15" x 25.41 = 381.15mm
Total is 627.15mm

So if 205/60/15 is the stock size, then you can run up to 265 in with, and a rolling diameter between 617 and 642mm

[ST185GT4]

So if 205/60/15 is the stock size, then you can run up to 265 in with, and a rolling diameter between 617 and 642mm

Thanks for the extra info, so what is stock size as listed in the association manual?

Is it 205/60/15?

On http://www.alltrac.net/phpBB2/viewtopic.php?f=8&t=19171

they say 195/60/15 is the usdm and edm oem winter tyre and its the largest stock.

Thanks for clearing up the o.d. calc CrUZida. Soooo easy. Feel a bit stupid on that one.

[CrUZida]

NFI on the stock size.
Find a sales brochure if the sticker on the car doesn't list it.

[ST185GT4]

Thanks again Cruzida.

Toyodiy lists the std wheel as 15x6.5JJ and tyre as 205/50/R15 88V

But no-one seems to list option tyre sizes

Surely there's someone out there with access to the tyre and rim manual info or who has been told by Vic roads or a tyre dealer?

[CrUZida]

Not all cars have options with tyres.
But I'd expect the ST184 and ST185 to have different sizes.