Where can you get your speedo calibrated?

[Dan F]

Hi All.
As above really. I would like to get my speedo adjusted so it reads the correct speed. Is this do-able and where can I get it done if so?

Cheers,
Dan.

[GorgeousGeorge]

alright dan

ok i just surfed up these..

http://www.dashtechservices.co.uk/index.htm

what you recon..

well that kept me busy for a bit :) :)

scott

[Dan F]

Cheers mate.
Might give 'em a buzz.

It doesn't mention if they can make the speedo needle read correctly though.

How do the cops get it done?

Dan.

[Pedro Fandango]

as the speedo's use an electric speed pulse & stepper motor now i'd of thought there would be a variable resistor on the unit somewhere to set the accuracy, but thats only a theory

i used my portable satnav to get a true speed reading & know that my speedo reads 5mph slow thru-out

[Dan F]

Hi Duane.
I have even thought about moving teh needle on the spline a little but that would be very hit and miss. Is there no way to get the ECU to adjust its interpretion of the signals it receives and passes to the speedo needle?

Later,
Dan.

[Pedro Fandango]

tbh i don't know anything about the speedo/pulse system so couldn't even say if signal goes thru the ecu or if the motor on the speedo does everything itself. Perhaps a tuner would does there own programming can confirm if there is anything in the ecu programme, if there is i would of thought with the help of a rolling road they could change the parameters to make it read accurate.

there must be someway of adjusting it, but how :sarcastic:

[Dan F]

there must be someway of adjusting it, but how :sarcastic:

Exactly. The police get their speedos calibrated so it is possible. Where to get it done though, and out of curiosity, HOW is it done?

[BlackBeast]

Phone your local Police HQ and ask :)

[Dan F]

Phone your local Police HQ and ask :)

D'OH! Never thought of that! :)
They can hardly say I am not being responsible or something can they, what with wanting a more accurate speedo....... ;)
Would prefer to go straight to where it is done though, if anyone knows where it is and who does it.

[SIAMBLUE]

I still have a ca;ibrated speedo here from my S70, will go and have a look at the sticker for you, as it is still on there, the speedo was accurate to my GPS by 1% at all speeds,

Gary.

[Dan F]

Cool. Cheers Gary.

[JackT5]

Damn, just sold mine or i could have looked but i remember the company name had just 3 letters and were in Nottingham, sorry i know it isnt much help.

[SIAMBLUE]

Hi Company is called IRS in Nottingham.

Gary,

[Dan F]

Cheers Gary.
I am guessing that is all the info there is? ;o)
Dan.

[SIAMBLUE]

That is all there is on my set of Clocks, i can take my clocks apart and have a look to see if there is anything untowards in there,

Gary,

[Dan F]

Whooa. Cool. :Banane32:
If you want to go that far, please do. It would be interesting to know if there is anything '3rd party' attached, or if it is simply a case of the correct placement of the needle on the centre spindle if the dial.
Cheers,
Dan.

[Sprintman]

Hi all, you could try this outfit, they've been around for quite a while :-

www.speedograph-richfield.com

Incidentally, according to my GPS my speedo [855AWD] reads about 4 mph fast.

[Dan F]

Thanks Sprintman.
At first glance it looks like they calibrate analogue speedos. Do they do electronic ones?
I am presuming that electronic speedos may be able to be calibrated via laptop or other such device.??
Cheers,
Dan.

[Sprintman]

Hi Dan, I don't have any personal experience of Richfield, just remembered the name from seeing their adverts and an article about them in a magazine somewhere. I guess that as the speedos are electronic they could be calibrated by laptop or perhaps there is some sort adjustment [variable resistor someone suggested?] that could be made on the speedo head itself.

[LittleGreyCat]

I am slightly puzzled when people say for instance "my speedo reads 4mph fast".

Does this mean that it reads 4mph when stationary? [ ;-) ]

I found this topic because I was about to grumble about my two Volvos.

Both seem to register about 10% faster than my GPS - I checked a while back with my Garmin eTrex but didn't fully trust the results.

However I was given a Mio C510E SatNav for Christmas and this also shows the speedos as about 10% fast.

[That is, 55mph on speedo, 50mph on GPS; 77mph on speedo 70mph on GPS]

I realise that GPS calculates speed 'as the crow flies' so will be inaccurate on twisty roads but it should be O.K. on the straights.

[I am now wondering what the GPS would show if I blasted around a large roundabout for several circuits at 40mph.]

As most/all speedos seem to be inaccurate (urban legend states that they are set deliberately high so the manufacturer can't be blamed if you get stopped for speeding) I also wonder how they confirm the true speed when doing the official fuel consumption figures.

I presume the mileage and MPG figures shown by the onboard computer are not influenced by the inaccuracies of the speedo?

You would think that any Volvo main dealer with a rolling road should be able to calibrate your speedo for you - but perhaps this is too easy.

Driving severl hundred miles to get the speedo recalibrated does not seem worthwhile.

Cheers

Dave R

[Alec Dawe]

Most speedometers read between 5 and 10% fast, especially Ford ones (!!).
Calibrating a manufacturers speedo might well be very expensive, depending on the type, and of course the calibration will become less and less accurate as your tyres wear down (makes a surprising difference!), and very much so if you change tyre sizes.

I check mine with my Garmin GPS, which I regard as accurate to within about 0.5%, and also I use the police timing poles. Most police forces have a couple of fairly small poles set up on a dual carriageway somewhere on their patch. The poles are exactly half a mile apart.. often look like broom handles stuck in the centre reservation, with coloured bands round the top 6" or so.

If you drive at exactly 60mph, and get someone to time how long it takes between the two poles should be 30 seconds), you can then easily work out how accurate your speedo is, and which way it reads (I've never found one reading slow!). Don't do this on your own!!! LOL.

The speedo on my S40 reads about 3% fast, the one on the 240 is about 2%fast, and my friend's Chrysler is about 12% fast... as it his mileometer!! (What reads 41 miles on my 240, reads 48 miles on his...,does wonders for his perceived fuel consumption!)

[PNuT]

i know a bloke who works for ford, the police will not accept a vehicle if the speedo is over 4% out

[insider]

The company who does the majority of the police calibrated speedo's is a company called IRS in Nottingham.

The "Police Spec" vehicles from Volvo don't need to go to IRS, they actually have a specific software upload for them, certainly the case for P2 V70's/S60's onwards.

For older spec's I'd suggest contacting IRS directly, but don't expect it to be anything like cheap.

The reason Speedometers "over-read" in "Civvy" cars is that it's actually illegal for a speedometer to under-read. ie it's fine if it reads 70 when you are really doing 67 but reading 70 when you are doing 75 is illegal.

Hope that helps some.