Speedo accuracy

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jantar, Aug 20, 7:18pm
A pet peeve of mine is the grossly inaccurate speedos fitted to most NZ vehicles. I see Fair Go is doing an item on it tonight as well.
intrade, Aug 20, 7:43pm
was it already on fair go i go wotch.
les6, Aug 20, 7:51pm
ford ranger 104=100k ,54=50k
checked with a gps
intrade, Aug 20, 7:54pm
yea wierd how that is news . What they forgot to mention and i said that more then one time. From new to worn tyre the Speed difference can be up to 4kph
I mentioned that when the pigs done there 4kph over bull$hit laws to gather more revenue . You try and walk at 5kph and not 7 its absolut impossible . but the pigs want you to stay within 4 or eaven 0 over.
its plain and simple revenue gathering proofen fact.
saxman99, Aug 20, 7:55pm
They all read high from factory on purpose.
intrade, Aug 20, 7:58pm
my one reads low now f. k paying all the extra road user charges to these theiving swines. my mb140 now does 99kph with the amarok tyres on 95 on odometer.
msigg, Aug 20, 9:53pm
Yes saxman99 you are correct, world wide this is done to prevent huge lawsuits that could happen. People are dumb if they thought their speedo was accurate.
bigfatmat1, Aug 20, 10:18pm
Its a ADR requirement Nz uses these rules.
kevymtnz, Aug 20, 10:41pm
its a requirement that they show over and not under 95% are 4kph over i had one that was showing 108kph but was only 100kph
sr2, Aug 20, 10:42pm
At what speed?
(Otherwise you claim is meaningless; i.e. a 'claimed' percentage would have at least made more sense).
tshop, Aug 20, 11:57pm
Speedos are a driveline reading and not engine HOURS ON. one should consider when buy a used vehicle especially coming from Japan, where its been running a med to high temp sitting in grid lock traffic.
Transmissions are usually the first to go their seals all hard and not holding oil pressure.
Im glad Im still able to work on a modern engine despite being a 60s baby boomer.
tamarillo, Aug 21, 7:22am
What? Can't make sense of that.
I believe it's a 10% accuracy and it doesn't matter above or below.
As a car mag reader I notice the actaul speed they record whilst it says 100 and some, all euro that I've seen, do get very very close, like 99 or even 100. Seems truer of up market models so maybe they assume users will stick to standard prescription tyres.
Standard cars go as low as 93 and are usually 95-96.
bill-robinson, Aug 21, 7:38am
if you want speedo accuracy find out what your car is doing, actual/speedo reading then change wheel/tyre size to get the correct reading/actual speed. it only costs money and time. then, as intrade says, put ner tyres on every 6 months and you can then thumb your nose to speed cameras
esky-tastic, Aug 21, 7:58am
Not forbidden bozoz that see the speed limit as a target ( often one to push past)

Since MOST speedos read faster than true speed you have to wonder what the speedo was reading when they got pinged for ‘105k’ ( how many have ever actually got a ticket for that speed?) and how much ‘revenue’ did it get?
Not enough to pay the cops wages.

BTW: I accept there is the odd car with a speedo reading substantially lower than true speed- for the drivers of those cars I have some sympathy.
jantar, Aug 21, 8:56am
If the error was a strict percentage then it would be easier to calculate. Unfortunately that is not always the case.

On one of my vehicles:
Indicated 53 kmh - Actual 50 kmh
Indicated 80 kmh - Actual 75 kmh
Indicated 96 kmh - Actual 90 kmh
Indicated 105 kmh - Actual 100 kmh

On another
Indicated 54 kmh - Actual 50 Kmh
Indicated 76 kmh - Actual 70 kmh
Indicated 110 kmh - Actual 100 kmh
Indicated 249 kmh - Actual 212 kmh
taipapaki, Aug 21, 9:03am
Is the odometer similarly afflicted with this deliberate calibration curse ? Am I paying 10-15% too much RUC ?
kazbanz, Aug 21, 9:04am
jantar that doesn't make sense.--I'm not doubting you just that the discrepancy should be linear.
kazbanz, Aug 21, 9:06am
Im curious--How often have you been to japan in the past 10 years?
jantar, Aug 21, 9:16am
I would agree that would seem logical. I was just as surprised when I saw the discrepancies between speedo indication, data logger and GPS speeds.
pauldw, Aug 21, 9:29am
That was the Aus ADR 18 rule up to 2006. Now the Aus rule follows Europe

"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."

The odometer on our car uses the abs wheel sensors and is within 1%. The speedo gets a modified signal from the car computer that seems to be always about 4km/h high rather than a %.
unideck, Aug 21, 9:33am
My Rx350 reads 112km when it’s actually dead on 100kms, 12ks out on a so called high end luxury vehicle lmao.
tgray, Aug 21, 9:41am
Reading 5k under is totally normal.
The vehicle featured reading 10k under however, is not.
tony9, Aug 21, 11:52am
An observation. A few years ago traffic on the open road seemed to travel at 95-100kph indicated. Now most seem to travel very close to 100-105kph GPS speed, which for me is around 112 kph.
bill-robinson, Aug 21, 6:53pm
jantar wrote:
A pet peeve of mine is the grossly inaccurate speedos fitted to most NZ vehicles. I see Fair Go is doing an item on it tonight as well.[/quote

are there special inaccurate speedos fitted for NZ then?
kcf, Aug 21, 10:31pm
Yup.

They pull cars going to NZ off their various international production lines, and fit extra wrong speedo's in them.