Legal or not

[Joe]

Good job apoll. Must be a nice feeling knowing you're now completely legal.

Does anyone know if we need to go to this sort of exercise in QLD, or is it only a NSW thing?

[Cam472]

How did you get your speedo checked? The engineer I spoke to stated the speedo needed to be checked at 40km/h, 80km/h & 120km/h but there are no roads in NSW where 120km/h is legal. All he and the RTA technical staff could offer was to take it to a race track (eg. eastern creek).

[apoll]

I had it done at a place in Lidcombe. Yep he took it up to 120km/h on some rollers. What a bit worried the car would shoot off and head into the street but it was ok.

[Cam472]

That's good to know, makes life so much easier. I did ask about putting it on a dyno but the engineer hasn't certified larger tires before and seemed to think it had to be done by his accurate GPS. I'll be taking my business to another engineer who has done it before now.

Cheers.

[Homer]

Geez some engineer "certifying" a speedo by GPS

Makes even more of a mockery of the whole stupid scenario.

[4wd26]

Good job apoll. Must be a nice feeling knowing you're now completely legal.

Does anyone know if we need to go to this sort of exercise in QLD, or is it only a NSW thing?

No avenue of doing this in QLD- cannot be engineered......

Other states its a similar exercise as the NSW one- i.e. doable. with a engineers certificate.

[jerrah]

Is the oversize tyre issue a matter of speedo accuracy or is there other considerations when the rule was written?

The factory speedo on my car is about 7% off so fitting a 265/75R16 would bring me closer to being accurate rather than the other way around.

Alternatively with NCOP 50mm rule we're still a few mm short. I'm guessing the rule is hard and fast but 4mm over seems awfully close.

[NowForThe5th]

There were other considerations, not just speedo accuracy, although, saying that, the determination of 50mm is a bit arbitrary.

Some tyre brands in the 265/75R16 size will just scrape in.

[docta.phipps]

Is the oversize tyre issue a matter of speedo accuracy

The factory speedo on my car is about 7% off so fitting a 265/75R16 would bring me closer to being accurate rather than the other way around.

ADR states that cars cannot under-read a speed but can over-read by 4kmph +10%

Other than the tyre size 50mm thing, I doubt there would be legalities about tyres affecting speedo as long as you don't start under-reading.

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[triton guy]

my Exceed reads 106 at 100 actual so it pays to check on stick tyres with a gps

[Joel]

Is the oversize tyre issue a matter of speedo accuracy

The factory speedo on my car is about 7% off so fitting a 265/75R16 would bring me closer to being accurate rather than the other way around.

ADR states that cars cannot under-read a speed but can over-read by 4kmph +10%

Other than the tyre size 50mm thing, I doubt there would be legalities about tyres affecting speedo as long as you don't start under-reading.

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I think it is less about speedo accuracy and more about the odometer. My odo only reads around 4.8kms over the 5 km check odo signs on the highway.