N.S.W. R.T.A. vehicle standards for tyres & others

[yowie Advanced Member Find all posts View Profile Close yowie]

Made some phone inquiries with the N.S.W. R.T.A. today, in relation to changing vehicle tyres.

Spoke to a knowledgeable old bloke (1300 137302 - technical inquiries, for tyres or anything else), who told me that vehicle tyres can be altered from the fitted tyre placard on vehicles, up to 26mm more in Width, and up to an Overall Diameter increase of 15mm, without need for re-certification of the tyre placard.

There are other information sheets, the one for tyres is number 9.

Go to RTA on the web, search for Vehicle Standards, then click on Vehicle Standards Information Sheets, then click the Information Sheet you need.


As a side issue, the RTA is installing Red Traffic Lights at the northern end of the Sydney Harbour Tunnel to control traffic congestion, and there will also be installed a Safety Camera, should you not stop for the red light. Due to start on 15th December.

Yowie.

[StormyKnight Advanced Member Find all posts View Profile Close StormyKnight]

Re: N.S.W. R.T.A. vehicle standards for tyres & others

Yes Yowie thats right, the issue is that 15mm is an absolute value, meaning 15mm is a lot if you have tyres on a mini, but it is not even 1 size up for a 4WD. Some 4wd tyres can have over 7.5mm of tread so they can be over when new & under when bald!

I've been thru the certification process to legally fit my 265/75R16's on my Prado since my insurance company advised that the car needs to be registerable for them to insure - which is fair enough I guess.....

I had to do the research & then advise the RTA, the tyre dealer & the certification guy the rules they each should be aware of. Oddly none of them had had anyone before ask them about oversize tyres & certification...

Anyway I can sleep at night knowing that the car is still insured. At the time it was $330 inc GST plus all the running around - it would be more if the speedo needed adjusting, but luckly it was already reading 3.5% fast so it read spot on with the BFG's fitted.

Cheers

[yowie Advanced Member Find all posts View Profile Close yowie]

Re: N.S.W. R.T.A. vehicle standards for tyres & others

Yes StormyKnight, 15mm applies to all tyres, and as you said, it would make a big difference on a mini. Cannot do much about it, as the RTA ruling applies to all.

I don't know what the difference is for a 265/75/16, however, the difference in overall diameter between a 265/65/17 (GXL standard size) and a 275/65/17 is 14mm in the Bridgestone range, and the 275 has a higher load rating and load index, which will assist with the extra weight of a bull bar, drawers, etc.

A Light Truck (LT) build in the tyre construction will give a stronger tyre.

As the tyre placard states, there are specified figures for Load Rating, Load Index and Maximum Speed, and any tyre fitted must be 'Not Less Than' these figures. I would say that most owners fit much larger tyres without knowing, or caring, that they will render themselves liable to cancellation of their insurance, should the vehicle be inspected after a serious collision, and be found to have not complied with the relevant laws and rules of their State. The fact that you did the correct thing probably shocked the various people concerned.

In regards to the speedo reading, vehicles cannot be sold where the speedo indicates below the actual speed of the vehicle, so most err on the side of caution and read above the actual speed. Not sure, but may be in the Australian Design Rules. A GPS gadget will usually give a more accurate speed reading.

Yowie.

[StormyKnight Advanced Member Find all posts View Profile Close StormyKnight]

Re: N.S.W. R.T.A. vehicle standards for tyres & others

Are not quite correct.....

the load rating must equal or exceed however the speed rating does not.....

In NSW the speed rating must be 140km/h or higher & if it is lower than standard a sticker must be placed in view of the driver indicating such. An example of the sticker is in the RTA documentation & the tyre dealer is supposed to supply it!

Oddly in Vic the speed rating can be as low as 110!

When I got the car certified we did use a GPS as the measurement tool & I now check every new car I drive since the error can be quite large. Mazda 6 for example was reading 17km/h too fast - I wondered why at 110km/h indicated I was getting past by so many trucks!

The Prado was about 3km fast & the work Xtrail is about 8km/h too fast.

No wonder people get annoyed with everyone sitting on an indicated 100km/h that can be anywhere from 83 to 100! All the trucks are set to right on 100km/h (or thereabouts ) it must be frustrating for them too!

Cheers

[yowie Advanced Member Find all posts View Profile Close yowie]

Re: N.S.W. R.T.A. vehicle standards for tyres & others

Maybe my comment does not read right, what I mean is the speed rating is 'Not Less Than' the fitted tyre, which is an 'S' rating on the 150 GXL.

[Guest Close Guest]

Re: N.S.W. R.T.A. vehicle standards for tyres & others

Maybe my comment does not read right, what I mean is the speed rating is 'Not Less Than' the fitted tyre, which is an 'S' rating on the 150 GXL.

What StormyKnight said is correct. You can fit tyres of a speed rating less than the fitted tyre/what the tyre placard says but not less than 140km/h, which is N.

VSI 9 Guidelines for alternative wheels and tyres

[yowie Advanced Member Find all posts View Profile Close yowie]

Re: N.S.W. R.T.A. vehicle standards for tyres & others

amts,

I re-read the RTA fact sheet, which states one can fit an 'N' rated tyre as a minimum (140 k/h), HOWEVER, this conflicts with the tyre placard which states in part "a speed category symbol not less than 'S' " (180 k/h).

It is a bit confusing, and to fit less than 'N' rated tyres, the vehicle must be re-certified, and a sticker affixed to the vehicle, as StormyKnight stated.

My original comments related to changing the tyres legally, and without having to have the vehicle re-certified by the RTA, and not affecting any insurance policy.

Yowie.

[Guest Close Guest]

Re: N.S.W. R.T.A. vehicle standards for tyres & others

An engineer's certificate is only required for a change to the diameter of the rim and tyre which exceeds the guidelines.
Windscreen sticker is required for fitting a lower speed rated tyre. No engineer's certificate required.

That is how I interpret it.

[mav Addicted PP Member Find all posts View Profile Close mav]

Re: N.S.W. R.T.A. vehicle standards for tyres & others

When it comes to speed it is worth noting that GPS speed readings can only measure speed in the horizontal plane and are inaccurate when speed is measured in the vertical plane. What this means is that your GPS will show correct speed on flat roads but will read inaccurately when you are traveling up or down hills or grades.