Ridiculous Speedometer Error and On Purpose !!!

[brad]

Where did you do 160kph legally to check it

I don't know about him but I've regularly done 160kph on a racetrack.

I also have access to hundreds of kilometres of private roads where I've done up to 190kph.

[Eaglen00b]

*SNIP*Japanese cars stick around the 5km/hr mark in general. *SNIP*

I can confirm that. My old 1995 75 series troopy reads 5km/h over right through the speed range. The speedo is at 5km/h even when stationary. I know the speedometer is probably buggered but it still reads consistently 5km/h over even at 110kmh actual GPS verified speed.

[Eaglen00b]

Where did you do 160kph legally to check it

Oh I misspoke. I meant to say IF I were to go 160kph GPS speed.....

[feenix74]

I assume he drove it to NT and used the no speed limit area

[Guest001]

Oh I misspoke. I meant to say IF I were to go 160kph GPS speed.....

LOL......

[gldgti]

I could say I have done 160km/h but noone would believe me because all my cars are slow diesels.

[theresanothersteve]

Interestingly an ELM327 device plugged into the OBDII port through DashCommand gives the same speed readout as my GPS. The dash (both needle and digital display), however, is about 5% optimistic. So the ECU knows how fast you are really going.

The VE Commodores I've owned were always 2 kilometres an hour faster, irrespective of how fast you were going.

[LukePolo]

My polo seems to stick exactly 5km/h over from 0-130km/h

I had a VR commonwhore a couple years back, that was bang on the money.

[themarvel2004]

Isn't one of the main reasons for this so that if you go for a larger wheel/tyre combo, the increased rolling diameter doesn't result in your speedo under-reporting (ie showing less than actual)? Otherwise you would need to get it recalibrated every time you change wheel sizes, which would be a hassle given the options you can get from factory.
The good part is - if you fit larger wheels any time down the track it is still ok!

I just use my GPS speed to confirm actual speed vs indicated on the speedo and all is good.
Have been doing this for the past 15 years - not sure why it is such a new revelation for people...

[Guest001]

Isn't one of the main reasons for this so that if you go for a larger wheel/tyre combo, the increased rolling diameter doesn't result in your speedo under-reporting (ie showing less than actual)? Otherwise you would need to get it recalibrated every time you change wheel sizes, which would be a hassle given the options you can get from factory.
The good part is - if you fit larger wheels any time down the track it is still ok!

I just use my GPS speed to confirm actual speed vs indicated on the speedo and all is good.
Have been doing this for the past 15 years - not sure why it is such a new revelation for people...

The main and probably only reason is to comply with ADR rules. The recommended tyre sizes are on the placard and if you go outside that you are on your own. As well there are State rules as to how larger you can go with wheel & tyre sizes. Most will keep your speedo legal but some may not. Up to you to comply