Does anyone know how accurate their speedo (on the dash, not sad swimming trunks) are. The reason I ask is that I've just bought a NAVMAN satnav device for my iPAQ which has an "accurate GPS speedometer". At an indicated 100mph on a private test track (M69), the GPS device records 92mph. Does the standard fit satnav on the Abarth show current speed? If so, how does it compare?

PS. I hope there are no coppers or saftey freaks out there!

Cheers,

Simon
'03 Stilo 1.8 Dynamic 3 door, Crystal Green.

It's fair to say that the speedo in every car over-reads about 10%. Don't ask me why or anything (saftey thing??) but it's a known fact. All the guys I know whith GPS devices e.g. Road Angel, Origin B2 report this.

cmc

1.6 Dynmamic 5 door.

Not sure if anyone else saw it, but there was a programme on BBC1 Watchdog last night, regarding mileage readings in the Pug 307.
The mileage was going up faster than it should, to the point where people would turn off their ignition, then turn it back on again to find an extra 5 miles on the clock...

...interesting when you consider how much dealers charge for a service after X many thousand miles [}]

If Speedo's over-do the actual speed by 10%, then wouldn't that imply our milage was 10% higher than it should be too?

Bren J
London

Crystal Green 3dr Stilo 1.2 Active

That's a fair point, but I don't know if the odometer that measures the speed is linked directly the speedo output reading i.e. the MPH it shows on the dial. I would hope not !!

1.6 Dynmamic 5 door.

I'm not overly sure whether the speedo and odom are linked to the same clocking device. It would make sense if they were though!
Would be better if they weren't, especially if cars overdo the actual speed!

Does anyone actually know whether they are or aren't[?]

Bren J
London

Crystal Green 3dr Stilo 1.2 Active

I have read that the digital speedos ... the one that Yaris has ... got the most inaccurate figures ... they add too much to your speed.

FIAT STILO 1.6 3dR Tiziano Red
Sub=Pioneer TS WX20LPA
AUTOMOBILE SK

Speaking of digital speedos, if anyone remembers the old Tipo DGT that had the most wildly inaccurate speedo of all time!

<h5>Click here for pictures of my Uno
Click here for pictures of my Brava

10% either way is the accepted standard for a speedo and my speedos are pretty accurate as they seem to show a nice large bulge at the local baths!

FIAT Stilo Sport. Pretty Much Bog Standard Really. Rear Roof Spoiler,
Sill Protectors, Aluminium Foot Pedals, Eibach 30mm Drop Springs.

I remember reading a letter sent into a car mag bout 4 years ago, about a bloke who bought a Skoda Octavia RS. He took it back because the speedo was 10% over reading, which he was not very happy about. Skoda were kind enough to replace it with a new one, and this one under-read by 5%. Lets hope the silly idiot racked up plenty of points over because of the under reading speedo[^]

I personally think a speedo over reading by 10% is a good thing. Makes you think your going faster then you really are. It can make a a big difference if you are caught speeding. Your speedo says 100, but your acutally doing 90. Probably a fixed penalty, or a court appearance. Caught doing 100, then a possible driving ban. 30mph over the limit means you may loose your licence.

2002 yellow Stilo 3dr JTD
JVC KDSH-9101 with DAB

Riff Raff .... another thing ... lets pray that the laser speedos that cops have are correct ))

FIAT STILO 1.6 3dR Tiziano Red
Sub=Pioneer TS WX20LPA
AUTOMOBILE SK

I've got an Origin Blue i fitted to my Stilo Abarth and that too has a GPS speedo fitted - it shows that the Speedo in my car is, too my surprise, extremely accurate at all speeds - an indicated 100MPH really is 100MPH.


--
Neil Barker

i have a punto elx. it is temperamental in the way it works. i will be doing 40 (on the speedo) but i will go through a speed trap which will then tell me i am doing 28. also when i go through a gatso camera i will slow down to 30 befor i get to the lines and see that the other cars are sailing through it whilst i am slowing down. i think they know something i dont!

I always thought the speedo was over by a bit, im hoping they are makes me feel safer going through speed cameras!

Bren J said:

If Speedo's over-do the actual speed by 10%, then wouldn't that imply our milage was 10% higher than it should be too?

Bren J
London

Crystal Green 3dr Stilo 1.2 Active

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I thought that too, although i recently got a plug in device for my Seat, it tells things like MPG, MPH, Throttle position and a whole host of other things, its a neat little thing which mouts in the dash easily.

Anyway, it plugs into the ecu plug so gets the info from the car. The MPH is the accurate reading, and is what my satnav says too. Although obviously the car reads about 3mph over.

So the car does know its actual speed, it just increases it by 3mph etc on its speedo so you have less chance of being cought speeding!

The mileage is recorded by the actual speed and not what the clocks are telling you

Think mine reads about 8 mph fast according to my mums tom tom, but would that be over the entire speedo or does it read more over the faster you go.

janevj said:

I have read that the digital speedos ... the one that Yaris has ... got the most inaccurate figures ... they add too much to your speed.

FIAT STILO 1.6 3dR Tiziano Red
Sub=Pioneer TS WX20LPA
AUTOMOBILE SK

Click to expand...

Rubbish. The one in mum's Yaris is more accurate than the speedo's in any of the Panda's!

According to my satnav the speedo it out by about 8% over the full range from 30 up to 70 mph (and higher:devil. Although the figures did change once I had my 18" rims fitted which meant that whereas the speedo used to show 77 and the satnav showed 70 now the speedo only needs to reach 75 to show 70 on the satnav.:hm:

I had a golf that read 80mph when the nice policeman told me i was doing 88mph. As for the tom toms ive never seen one read the same as a speedo.

i have a tomtom 6 sat nav, and doing 70 on the motorway in the car is indicated at around 61mph on the sat nav. Doing baout 80 is indicated as 70 on the sat nav. Which one would you beleive to be the most accurate?

Oakley28 said:

i have a tomtom 6 sat nav, and doing 70 on the motorway in the car is indicated at around 61mph on the sat nav. Doing baout 80 is indicated as 70 on the sat nav. Which one would you beleive to be the most accurate?

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Well being that a sat nav works its speed out in pretty much real time by the distance that the GPS signal has travelled the Sat-Nav is more accurate.