Tyre Size THE DEBATE THE LAW

The relevant text - I didn't believe this until I found it:

"The rolling diameter of any tyre fitted to a passenger car or passenger car derivative must not be more than 15mm larger or 26mm smaller than that of any tyre designated by the vehicle manufacturer for that model.

The rolling diameter of any tyre fitted to an off-road passenger vehicle or a commercial vehicle must not be more than 50mm larger or 26mm smaller than that of any tyre designated by the vehicle manufacturer for that model."

So an OFF-ROAD passenger vehicle may have an increase of up to 50mm!

BUT, this is out of the National Code of Practice - is it law? State by state? Will insurance companies be forced to recognise it?

Sounds good, OFF ROAD Passenger vehicle to legally have increase up to 50mm, but i agree with the question is this legall, do the states individual transport authorities view this as legislation. Thanks for the info Phil and Scubaroo, but we need to find out if it is legall?

At the moment, I believe that State laws override the Commonwealth laws, which is why we have different tyre laws for each State. I really hope this document becomes adopted by all the States, so we have simple rules across the country, and they are sensible. I think its still a DRaft document at present.

And just as an aside, I don't believe that anyone has ever been pinged for being 30mm over with a 4wd tyre.

Cheers
phil

The operative word here isproposed. These are only for discussion right now and have to be agreed to and adopted by all statutory bodies. I personally hope they get through. It also includes a maximum 50mm body lift plus spring lift plus up to 50mm more tyre diameter providing the whole shebang does no exceed a total of 150mm higher than standard.BUTit will have to be engineer approved.

They have been talking of national rules for 15 years.

Dont get excited yet fellas...

It will go thru each states governing body 100 times in the next 10 years, be argued against/for each time, then modified, then they will bring out Draft # 19048023984023948.b-s1 and then and only then *MAY* it happen.

By the time it happens,there will be no oil left.

It is not the tyre placard but 15mm larger than what is listed in the handbook as fitment for that vehicle. My tyre placard says 265/70r16 but the owners manual lists 245/85r16 as fitment on some models. So it is 15 mm larger than 245/85.

Just out of curiosity I don't have my handbook on me for 2005 SR5 Hilux, i don't suppose anybody reading knows what the tyres specified are for a hilux sr5 2005 in the handbook???

Flyology

Could you kindly ask your mate in the traffic branch about increse in rolling diameter, thanks for your help with the handbook, i agree a 100% with you, i love your suggestions of 50mm over but i don't think QLD transport do!

You would think Fed over state, but it aint always the case.

"Either way if you disclose it to them that you have fitted the wheels and tyres and they accept that on the application, you should be ok."

If your car is unroadworthy, it doesnt matter what they have accepted.

15mm is the rule for 4wds at the moment.

Federal legislation will only prevail over State legislation where the Constitution gives the power. Of course in areas where the States have passed enabling legislation for a Federal statute - the Federal law will prevail in cases of conflict.

All you need to do is ring the relevant section of your State Authority. It is the RTA in NSW, not sure what it is called in other states. Ask to speak to one of the engineers and tell them what you want to do and ask them if it is legal or if you can get an engineers certificate to cover it. Each state publishes a list of certifying engineers - there is one somewhere on the RTA's website. I have seen it. Ring one of them. They are the ones that have the power to certify mods and make them legal, but they must comply with a certain code and they will not get anything certified.

Years ago, I put a back seat in a Daihatsu Diesel 4WD and I had to have it certified. It turned out that the certifying engineer was someone I went to school with and I got it done for a slab of beer and a few visits to his house. He also loaned me the ADR's and made me do the drawings to show whether the seat belt mountings could be legally done in the confines of the space. He agreed with it, I had it done and he inspected the welds, mountings, etc. Then the bastard at the RTA tried to tell me it was illegal and he wouldn't regsiter it, despite my engineering certificate. He said that in the case of fire, the people in the back seat could not get out. I countered that with "Then in that case, all mini minors are illegal too. He reluctantly registered it. I told the engineer who said that the guy hated him and probably read his signature and decided to make a statement.