Vf sv6 tyres

[Derekthetree]

No, the difference in 45 to 50 series tyres is 5% of the width, not 5mm.
5% of 245 is 12.25mm.
So a 245/45 has a side wall of 110.25mm
a 245/50 has a side wall of 122.5mm

You learn something new every day!

 

[mpower]

Legal requirement which makes it an industry practice world wide regardless of the laws of each country

the "legal requirement" is not to have the speedo display less than the actual speed.
The requirement is that the speedo must not display greater or less than 4 percent of the vehicles true speed so the manufacturer could legally make the speedo show 100 if you were doing 103 but the "industry practice" is to make the speedo show about 3% more than the speed you are actually doing which is why most vehicles display 100 when you are actually doing 97~98.

It is compliance not practice, this is an important thing to note because without this guidance manufacturers would not do this they are more than capable of making speedo's accurate.

Also variances have been demonstrated to vary between manufacturers. Toyota in particular have been noted as reading a fair bit lower than most other brands.

 

[stooge]

It is compliance not practice.

Compliance would be making the speedo read no more than 4 percent more or less than the actual speed which would include displaying the exact speed.

Practice is the majority of manufacturers deciding to display the speed with 3% added.

Dont get those two confused

That guidance has nothing to do with the manufacturers not displaying the actual speed because it is perfectly legal for them to do so.
Compliance would also allow them to show that you are doing 100 when you are actually doing 103.

If a 2006/2007+ toyota displays more than 4 percent offset it does not meet australian design rules and is illegal.

Any vehicle pre 2006 can have a 10 percent variance.

 

[RossK]

I find the VF speedo annoying, it reads 104 when i'm doing 100 by the gps etc.
But, previously, the VT read 100 when doing 100,
VY read 100 when doing 100
and the wifes VE reads 100 when doing 99.
If they can make them read accurately, do it, not 4% low.
Grrr.

From the Old angry man yelling at clouds

 

[mpower]

I find the VF speedo annoying, it reads 104 when i'm doing 100 by the gps etc.
But, previously, the VT read 100 when doing 100,
VY read 100 when doing 100
and the wifes VE reads 100 when doing 99.
If they can make them read accurately, do it, not 4% low.
Grrr.

From the Old angry man yelling at clouds

The ADR changed and manufacturers are required by law to do this to comply with the standard. This also applies to the OP, who by making his speedo out could make his vehicle unroadworthy. This could attract a defect notice if the speedo no longer meets the standard set out in the ADR.

Safety

Tips and advice to help keep you safe on the road.

www.racq.com.au

Australian Speedo accuracy standards
Australian Design Rule 18 sets out the accuracy standards for vehicle speedos.

Until July 2006 this rule specified an accuracy of +/- 10 percent of the vehicle’s true speed when the vehicle was travelling above 40km/h.

That is, at a true vehicle speed of 100km/h the speedo could indicate between 90km/h and 110km/h.

An odometer accuracy of +/- 4 percent was also a requirement.

From July 1 2006 a new standard began its phase in and by 1 July 2007 all new vehicles had to comply. The new standard requires that:

• The speedo must not indicate a speed less than the vehicle’s true speed or a speed greater than the vehicle’s true speed by an amount more than 10 percent plus 4 km/h.
• Odometer accuracy is no longer defined.

What this means:

• For a vehicle travelling at a true speed of 100km/h, the speedo must read between 100km/h and 114km/h. The effect of this is that many drivers will find that at 100km/h they are driving up to 14km/h below the speed limit if they rely on the vehicle’s speedo.
• The speedo must always read 'safe', meaning the vehicle must not travel faster than the speed indicated by the speedo.

This change was made to align Australian vehicle rules with those already in place in Europe. It applies to all Australian motor vehicles except mopeds.
Dealers will generally not attempt to correct speedo error unless it exceeds the legal requirements.

 

[RossK]

And thats the annoying bit, they can legally make them read 100kmh when doing 100kmh and they can make them to do that, but they choose to now calibrate them to read 4% higher than the actual speed.
The law allows them to read 100 at 100, so why not do it.
they just cant read 100 when your're doing 101.

Here comes another cloud......

 

[mpower]

And thats the annoying bit, they can legally make them read 100kmh when doing 100kmh and they can make them to do that, but they choose to now calibrate them to read 4% higher than the actual speed.
The law allows them to read 100 at 100, so why not do it.
they just cant read 100 when your're doing 101.

Here comes another cloud......

because if there was a variance they could cop very big fines.

 

[Forg]

And thats the annoying bit, they can legally make them read 100kmh when doing 100kmh and they can make them to do that, but they choose to now calibrate them to read 4% higher than the actual speed.
The law allows them to read 100 at 100, so why not do it.
they just cant read 100 when your're doing 101.

The reality is that they're not ALL reading 4% higher, there's some variation, and if they were aiming at "exactly correct" then that variation would have some cars actually reading under the real speed.

WE know it's all political, THEY know that we know it's all political, yet the games still get played ...

 

[RossK]

yeah I know, but 4%!. I'll bet they could have done better.
The fact that of my previous 3 holden, the worst was 1% suggests they have the technology to do it.

Hey, that cloud moved.....

 

[panhead]

And thats the annoying bit, they can legally make them read 100kmh when doing 100kmh and they can make them to do that, but they choose to now calibrate them to read 4% higher than the actual speed.
The law allows them to read 100 at 100, so why not do it.
they just cant read 100 when your're doing 101.

Here comes another cloud......

It's better to be reading a little lower than you think rather high, that way the manufacturer's don't have to worry about complaints if there customers keep getting hit for speeding.

If you're not happy with it, have it corrected the next time you get a tune.






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