"whisky-dave" wrote in message
...
On Tuesday, 29 September 2015 21:23:10 UTC+1, Rod Speed wrote:
"whisky-dave" wrote in message
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On Tuesday, 29 September 2015 13:26:18 UTC+1, Dave Plowman (News)
wrote:
In article ,
brightside S9 wrote:

Manufacturers will normally deliberately calibrate their speedos to
read 'high' by some amount between 100% and 110% to keep themselves
within the law.

It also means the car shows a higher top speed than reality. Better
MPG.
And needs servicing more frequently. So a win win win for the makers.

In these days of pulse counting speedos, there is no need for the same
sort of tolerance as once. Only thing which will effect the reading is
tyre wear - which makes it read on the 'safe' side anyway.

No the thing that effects the reading is the software and the digits
it chooses to show on the display.
I thought VW emissions reading will have taught everyone that.

That doesn't involve displaying anything.

Yes it does, it's was plastered on their website how low the emissin
levels are.

That isn't the displaying being discussed and you know it.

So whatever a car says it's doing means little.
It can't be that difficult to fudge speedometers to under read.

It's rather more complicated than it looks at first
given that the rate at which you get pulses depends
on the tyres installed and the pressure in them and
how much they have worn etc.

simple just halve the number of pulses and the speedo reads half of
what it would have read.

Even sillier than you usually manage.


The police should use their methods of reading speed
which should be checked and calibrated regualry.

They obviously are.

yes I know isn't the error allowed in Aus about 2-3% .

It varys by state. All except Victoria in theory allow
something like 5%, but in practice, particularly with
the change from 60KMph to 50K in built up areas,
you don't actually get booked doing 60.