31" Mud tyres legality (is 15mm really the legal limit?)

[glenhendry]

Hi All

After much consternation I finally decided to get 245/75-16 (30.5" (775mm)) mudders on my 2000 4.6. I have 16" rims for off roading, as my 18" hurricanes have nice new safe Cooper's road rubber on them.

Standard 18s are 255/55-18 (29" (737mm)).
Standard 16s are 235/70-16 (29" (737mm)).
BFG MT KM2s are 245/75-16 (30.5" (775mm)). The main reason I want the larger size is to increase my diff to dirt measurement (and also rim to dirt).

Upon ordering Bob Jane at Coorparoo (dutifully) said that 15mm is the maximum legally allowed to increase from the standard tyre diameter.

This post (Legal Tyre sizes in QLD - AUSJEEPOFFROAD.COM (http://www.ausjeepoffroad.com/forum/showthread.php't=99622)) suggests that will change or has changed to 50mm.

I dont much like the thought of running the risk of my insurance not paying for the AMG CL500 that my wife rear ends, so is everyone just running the gauntlet here or is there another interpretation to the applicability of alternative 4wd tyres?

[DT-P38]

Not sure about legalities but I did recently hear the 2 & 2 law was now in nationally. That is, maximum 2 inch lift and 2 inch tyre increase. Beyond that engineers certificate required.

Haven't seen this formally announced or communicated though.

[glenhendry]

I have the answer (for Qld at least). I called the vehicle mod mob on 07 32534851.

15mm above the tyre placard is indeed the upper limit. You can go 1.5x wider than OEM, but only 15mm more in overall diameter. See http://bit.ly/oKNGtP.
Bollocks. That will make my new mud tyres pretty pedestrian.

Even if Qld does take on the National Code of Practice for Light Vehicle Modification, they said that they may except some of those codes. eg, even though the National code allows for 150mm body lift, Qld will be sticking with the current limit of 50mm max. The same may be true for tyres. No date is known for the adoption of the National Code in Qld.

[wanglemoose]

funny none of my landrovers ever come with a tyre placard on the vehicles :angel: and ive never had a problem with the insurance or police for 265/75/16's.
this is including the disco 2 that was written off 18 months ago. the simple thing with 4wd's in qld is the keep changing their mind on the rules which means you can do pretty much anything.

[glenhendry]

For posterity: I went the 245/75-16s in the end. I got Wrangler Duratrac mudders for $300 each. They are 31.6". They fit fine and look & perform good, they only scrub in carparks at full lock and I haven't removed anything from the rig.

[VladTepes]

Is that overall diameter or rolling diameter ?

[glenhendry]

What does "rolling diameter" mean. If we meant "rolling" then we should be talking about circumference I think? Overall diameter is 12 oclock to 6 oclock, and that is the important measurement I believe.

[Keithy P38]

Good choice in size. My KM2's are 255/70/16 and come in just under 31". I've never had any hassles, and the tyre shop mentioned that would be as big as they 'legally' advise me to go. Any bigger and it was not their suggestion. I'm also in QLD.

Cheers
Keithy