Outer Limits 4x4 Board

I have my car engineered in NSW with 12.5" wide BFG tyres on 8" rims.
While this is on my papers, I realise that most manufacturers (Goodyear/BFG etc.) give a recommended minimum rim width of 8.5" which is not legal for my rig.
Cooper seems to be the only one who list 12.5" tyres as being OK on 8" rims.

SO:

- Are MTR's and BFG Muds definitely a 'no go' for 8" rims?

- Is anyone aware of other similar all-round mud tyres in 35x12.5 that are approved for 8" rims in Australia?

Cheers

Is the data supplied by the tyre manufacturers regarding minimum rim width a recommendation or is it the law?

Are these rim widths passed as legislation in regards to mounting tyres on rims? Or is it up to the cutomers/engineers and RTA's discretion still?

HotFourOk wrote: Is the data supplied by the tyre manufacturers regarding minimum rim width a recommendation or is it the law?

The tyre manufacturers use the term 'Appoved rims' - from 8.5 to 11". They also offer a reccomended rim width - 10" in most cases for the 12.5" tyres.

HotFourOk wrote: Are these rim widths passed as legislation in regards to mounting tyres on rims? Or is it up to the cutomers/engineers and RTA's discretion still]?

I think that the engineer can only approve a tyre height/track width change up to a certain RTA approved limit.

Isn't there some Australian tyre industry hand book which is considered the "Bible" for these sorts of questions?

Scott

The "Tyre and rim association manual" is what police RTA and DOT reach for when checking if your tyres are legally mounted. This however can be over-ruled by a manufacturers specification (tyre manufacturer). If a tyre manufacturer says a 14" wide tyre is OK on a 4" wide rim then DOT cant do anything about it. But then, the TYRE manufacturer will be the ones in court if theres ever an accident.

DOT RTA POLICE, all they want to do is make sure its not thier ass on the chopping block if a fatality is involved. If you can provide documentation from your tyre manufacturer saying your tyre/rim combination is legal there is nothing RTA DOT Police can do about it.

-Scott- wrote:Isn't there some Australian tyre industry hand book which is considered the "Bible" for these sorts of questions?

Scott

Perhaps... Assuming it is a vailable over the net, does anyone have a link to such a handbook?

John H wrote:Perhaps... Assuming it is a vailable over the net, does anyone have a link to such a handbook?

I think its one of those Secret docos, some people on here do have it though.

8" is widest you can go in aust isnt it?

MADZUKI wrote:8" is widest you can go in aust isnt it?

nope

MADZUKI wrote:8" is widest you can go in aust isnt it?

I'm happy with 8" rims.
Just want to make sure that my 12.5" wide tyres are legal on 8" rims.

John H wrote:

-Scott- wrote:Isn't there some Australian tyre industry hand book which is considered the "Bible" for these sorts of questions?

Scott

Perhaps... Assuming it is a vailable over the net, does anyone have a link to such a handbook?

you have to buy it, i have an older copy (2000).

MADZUKI wrote:8" is widest you can go in aust isnt it?

8" is the widest that can legally (ADR) be fitted to a 4WD unless otherwise spec'd by the manufacturer.

Just called Goodyear in OZ and as far as they are concerned an 8.5" rim is as narrow as you can go with a 12.5" MTR - no if's or buts.
The local tyre shop says they often fit 12.5 MTR's to 8" rims and recon it is fine. I know that it is fine in practice but I'm trying to keep my POS legal.
I have had a good run with MTR's in the past but I think that I will have to go with Cooper STT's for the simple reason that they are listed by Cooper in Australia as being OK for 8" rims.

John H wrote:Just called Goodyear in OZ and as far as they are concerned an 8.5" rim is as narrow as you can go with a 12.5" MTR - no if's or buts..

they were also happy that a 33 measured 32.1...