Tyre/wheel legalities

[Jeo]

Not sure what the laws are in the ACT, but we are diferent to NSW on many points. Ring Dickson and they should give you an answer.

[lucifuge]

I came across this on another forum:
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In Australia applicable traffic regulations differ in each state, therefore guidelines for alternative wheels & tyres are different for each state. When checking the legality of alternative wheels & tyres, it will be necessary to refer to the vehicle's tyre placard.
From January 1, 1974, all vehicles that comply with Australian Design Rules (ADRs) have a tyre placard attached. From July 1988, a statement of minimum requirements for tyre load & speed ratings were added to the tyre placard

Following is a list of the minimum requirements for alternative wheel & tyres for Australian States & territories. These requirements apply to passenger cars (and utes) unless otherwise stated. O.E. size refers to any tyre size listed on the vehicle's tyre placard.

An alternative tyre size is a tyre size that is not listed on the vehicle's tyre placard.

Fitment of wheels & tyres that do not meet these requirements require an engineering certificate to be a legal fitment.
New South Wales: The overall diameter of alternative tyres must be not more than 15mm larger than the largest O.E. size or 15mm smaller than the smallest O.E. size. Minimum speed rating is N (140 kph).
Victoria: The overall diameter of alternative tyres must be not more than 15mm larger than the largest O.E. size. Minimum speed rating is equivalent to the highest state speed limit, which is 110kph or K.
Queensland: The overall diameter of alternative tyres must be not more than 15mm larger than the largest O.E. size or 26mm smaller than the smallest O.E. size. Minimum speed rating is N (140 kph).
South Australia: The overall diameter of alternative tyres must be not more than 15mm larger than the largest O.E. size or 15mm smaller than the smallest O.E. size. Minimum speed rating is S (180 kph) for new tyres fitted to passenger cars or 140 kph (N) for retreads. Minimum speed rating for four wheel drives is 130 kph (M).
West Australia: The overall diameter of alternative tyres must be not more than 15mm larger than the largest O.E. size or 15mm smaller than the smallest O.E. size. Minimum speed rating is S (180 kph) for new tyres fitted to passenger cars (or the vehicle's top speed if lower than 180kph), or 140 kph (N) for retreads. Minimum speed rating for four wheel drives is N or 140 kph.
Tasmania: No specific ruling in maximum or minimum overall diameters of alternative wheels & tyres, Except that both must comply with Australian Tyre & Rim Association standards. The speed rating must be equal to or better than the vehicle's top speed.
Australian Capital Territory: The overall diameter of alternative tyres must be not more than 15mm larger than the largest O.E. size or 26mm smaller than the smallest O.E. size. Minimum speed rating is S (180 kph) for new tyres fitted to passenger cars or 140 kph (N) for retreads. Minimum speed rating for four wheel drives is 140 kph (N).
Northern Territory: The overall diameter of alternative tyres must be not more than 15mm larger than the largest O.E. size. Minimum speed rating is that stated on the tyre placard.
Check with the transport authority in your state to confirm the legislation that applies to you:

The NSW Roads and Traffic Authority
VicRoads
Queensland Mainroads
Mainroads Western Australia
Northern Territory Dept of Transport and Works
Dept of Transport Tasmania
Transport SA
ACT Dept of Urban Services
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Still bloody confusing. My tyre placard says 205s, no other options.

I would've loved to put the 17x9's with 235/40/17s on mine, but maybe i can't: ---> http://www.good-win-racing.com/mazda-talk/viewtopic.php?t=811&highlight=17x8

[Charlie Brown]

Lucifuge,

The standard NC tyre is 205x45x17 and has a diameter of 616mm.
I’m running 215x45x17s which have a diameter of 626mm.
A 235x40x17 tyre has a diameter of 620mm which is fine but…….they really need to go on a 8.5” rim. Sure you can put them on an 8” rim but their performance will be worst than a 225 on an 8” rim.

Some other points to remember are what tyres (manufacturers) are available in that size? Michelin don’t make a 235x40x17 PP2. You need to go to the Pilot Sport and that’s big $$$$$$. Toyo R1R also don’t come in that size but the T1Rs do.

As for guard rolling, my track tyres being very square shouldered (225x50x16 DO1s on 8” rim) would probably equate to a 235 road tyre. I had rubbing on the rear left over large bumps so I did a very small guard roll using a hair dryer to heat the paint and then a heavy gauge PVC pipe to move the lip away only about 2mm. No problems since.

My NC is also down 40mm which is 8 – 10 mm more than yours so I would expect that you will have no problems with catching a guard with the tyre provided you keep to an offset not lower than 48mm, which you must to stay legal on an 8” rim.

Another small point is that I did notice a difference in the acceleration going up to the 215x45 road tyre. It wasn’t as crisp. Also my track tyre/rim is just 0.75 kgs heavier than the road setup but I notice the difference there also. I’d strongly suggest that you check out the weight of the rim and tyre combination before making your final selection. Keep it as low as you can.

[StanTheMan]

Great summary.

This has been discussed countless times on this forum.

There is another document in this forum from A tyreplace which summarised all the different states wheel & tyre fitments.
but I haven't been able to find it again.
Why this hasn't become a sticky is beyond me.

Every couple of months the question props up.