Hi, I have been borrowing my mother's new 2016 Citigo and it's speedo is over reading by 5-6mph! I double checked running two SAT navs and also those radar speed signs.

 

The Odometer is also adding on more miles when compared with the GPS trip data.

 

Has anyone the same problem and know of a solution to correct it? VCDS perhaps?

 

21 minutes ago, C50 said:

Hi, I have been borrowing my mother's new 2016 Citigo and it's speedo is over reading by 5-6mph! I double checked running two SAT navs and also those radar speed signs.

 

The Odometer is also adding on more miles when compared with the GPS trip data.

 

Has anyone the same problem and know of a solution to correct it? VCDS perhaps?

 

 

It's normal. They all do it. Every car does it.

 

Under construction and use, Speedos must not under read (so you can't blame the speedometer being wrong of you're caught speeding), but it's ok for them to over read, so they typically over read by 5-10% (so if you guage your speed by the speedometer you will be within the limit).

 

Odometer readings are generally ok though, and GPS logs can be a little low as they are always shaving a bit off on corners; their distance will be a number of straight lines rather than a continuous curve. Actually, on that basis the GPS speed will be *slightly* off on corners, but not by enough to make any difference. With the odo, it's adding up a lot of tiny differences over time.

 

Basically it's fine, don't worry about it

A few mph out is ok but this is over 5mph at 65-70mph. That's a whole increment on the speedo which is annoying otherwise what's the purpose of the increments.

 

The odometer is definitely affected. Over a mile is added on a 13mi trip hence there must be a solution to this?

Sounds daft, but tyre pressure can make a difference.

Also, is it still on the original alloys/tyres or have they been changed?

(Small change to the radius can make a big difference to the circumference).

 

Yup, all standard and using the recommended tyre pressures.

 

I'm quite appalled on the tolerance especially on such a new-ish car.

 

I did a search on VCDS correction but nothing for a Citigo came up.

I remember reading about a Ford Cortina from the 80s that was actually doing 72mph when the speedo showed 90.

 

On my citigo I find I'm doing 28 when it reads 30, 46 when it reads 50 and 65 when it reads 70.

3 hours ago, C50 said:

Yup, all standard and using the recommended tyre pressures.

 

I'm quite appalled on the tolerance especially on such a new-ish car.

 

I did a search on VCDS correction but nothing for a Citigo came up.

 

Perhaps I'm being particularly dim (it's not unknown), but I can't see why you're appalled.

 

If i can refer you to Hansard (https://publications.parliament.uk/pa/ld200001/ldhansrd/vo010312/text/10312w01.htm) and quote "The Road Vehicles (Construction and Use) Regulations 1986, as amended, allows the use of speedometers that meet the requirements of EC Community Directive 75/443(97/39) or ECE Regulation 39. Both the EC Directive and the ECE Regulation lay down accuracy requirements to be applied at the time of vehicle approval for speedometers. These requirements are that the indicated speed must not be more than 10 per cent of the true speed plus 4 km/h. In production, however, a slightly different tolerance of 5 per cent plus 10 km/h is applied. The requirements are also that the indicated speed must never be less than the true speed."

 

With that in mind (according to the tolerance laid down in the regs)...

 

At 30, your speedo can read anywhere from 30 to 37.7mph.

 

At 70, it can read anywhere from 70 to 79.7mph

 

It has do do this reliably through the service life of the car, so allows for wear and tear of speedometer components and for tyre wear too.

 

Surely that makes it reasonable for the manufacturer to calibrate the speedometer such that it is likely to stay legal during that period, noting that if they set it to read exactly 30 at 30 when new, the slightest underreading would make it illegal?

When I had a microlight it had to have a note (placard) on the instrument panel giving 'real' air speeds as against the indicated one. This was sorted during the initial flight test using a GPS to check indicated speeds. Not of great importance since the stalling speed could be checked by just stalling & checking the indicated speed. So, happens on aircraft as well as cars. Live with it.

16 hours ago, Gyp said:

 

Perhaps I'm being particularly dim (it's not unknown), but I can't see why you're appalled.

 

If i can refer you to Hansard (https://publications.parliament.uk/pa/ld200001/ldhansrd/vo010312/text/10312w01.htm) and quote "The Road Vehicles (Construction and Use) Regulations 1986, as amended, allows the use of speedometers that meet the requirements of EC Community Directive 75/443(97/39) or ECE Regulation 39. Both the EC Directive and the ECE Regulation lay down accuracy requirements to be applied at the time of vehicle approval for speedometers. These requirements are that the indicated speed must not be more than 10 per cent of the true speed plus 4 km/h. In production, however, a slightly different tolerance of 5 per cent plus 10 km/h is applied. The requirements are also that the indicated speed must never be less than the true speed."

 

With that in mind (according to the tolerance laid down in the regs)...

 

At 30, your speedo can read anywhere from 30 to 37.7mph.

 

At 70, it can read anywhere from 70 to 79.7mph

 

It has do do this reliably through the service life of the car, so allows for wear and tear of speedometer components and for tyre wear too.

 

Surely that makes it reasonable for the manufacturer to calibrate the speedometer such that it is likely to stay legal during that period, noting that if they set it to read exactly 30 at 30 when new, the slightest underreading would make it illegal?

 

I have explained why I am appalled and only here to see if there's a solution. We are in the year 2018 where nano tech exists! All my previous non VAG pre 2004 vehicles were never this out (Japanese, Proton, Kia).

 

I guess I like things to be accurate and especially on a speedo if I look at it daily. They ought to sack whoever is calibrating the speedos at the factory!

 

 

 

Looks like it may well be possible with VCDS, look here: http://forums.ross-tech.com/showthread.php?402-Speedometer-Calibration

Haven't time to read that just now, but it seems like there's scope.

Odo reading will be affected because it uses exactly the same data stream from the ABS module.

With the Speedo you know it is happening and you can make allowances.

 

As to the odometer / mileometer,  how many extra miles does it add for every 100 miles or 1,000.

 

As i change tyre size on cars there might sometimes be a difference between the 'Trip' setting and the odometer,  but it is like 1 or 2 10th's of a mile.

As to the GPS is that allowing for the ups and downs.

 

I have 3 GPS on when cycling on my electric bikes , the inbuilt one with the motor that is set by wheel circumference, then the Tracker GPS i use, 

and the Garmin GPS on my HR Monitor on my wrist.

The GPS on the Phone and the one on my wrist do not give the same distance as the bike measures, it measures the actual miles the wheels turn.

Edited 17 August, 20187 yr by Offski

The odometer error will be the same as the speedo error.

 

Which is why i am asking, to see if it is adding 5 to 6 miles to every 100 to the OP's car.

It does  not on every vehicle, i know because i have checked often enough.

 

Adding an extra 600 miles to an annual 10,000 mile a year vehicle is a bit of a no no.

Someone that does 20,000 miles a year of which there are plenty, or those paying extra mileage charges on 20,000 miles of driving having 21,200 miles showing.

It will do on vehicles with ABS wheel speed sensors as the sole data input for speed and distance, which is pretty common these days.

Distance = speed x time.

I can assure you that over the 6 years i did the same 145 miles twice a week in Mk2 Fabia VRS the 145miles stayed as 145 miles every trip, 

yet the speed misread depending on the tyre sizes i fitted, and i changed the cruise control setting to suit the speed i wanted after checking using the V-Box i had.

 

The only time the 145 miles did change was when the new motorway extension was opened.

Then the tip was 3 miles shorter, same distance as it shows today or any day which ever vehicle i am driving.

Edited 17 August, 20187 yr by Offski

I can't explain that except to say that anecdotal data is usually of little value to science.

Which is why we need to know if the OP's Citigo drives for 400 miles but shows that it went 424.

Not that it matters, except maybe for those that are going for the 700 miles from a tank with a Citigo.

(or those buying high mileage cars that turn out to have not done so many miles....)

http://briskoda.net/forums/topic/453741-700-mile-tank-range 

Edited 17 August, 20187 yr by Offski

On ‎16‎/‎08‎/‎2018 at 12:00, C50 said:

The Odometer is also adding on more miles when compared with the GPS trip data

 

I read that, and you say the extra MPH will be the same as the extra miles, so 600 miles for a 10,000 mile a year car is a lot.

Especially when the Fixed Servicing is at 9,400 miles or 372 days which ever comes first.  No wonder they usually say next service @ 10,000 miles and are not concerned about accuracy..

10,000 miles on the Car meaning less actual miles covered.

 

They need to start servicing like generators, plant, aircraft etc, hours engine running.

7 hours ago, Wino said:

Looks like it may well be possible with VCDS, look here: http://forums.ross-tech.com/showthread.php?402-Speedometer-Calibration

Haven't time to read that just now, but it seems like there's scope.

Odo reading will be affected because it uses exactly the same data stream from the ABS module.

 

Wow, you're GPS crazy lol!

 

Thanks, I did some searches and it seems to be common with the VAG cars. Its seems that VCDS can adjust how the car counts the pulses to compensate for different wheel circumferences for other models. Unfortunately, I couldn't find anything for the Citgo though but maybe some VCDS expert with a CItigo/ UP/ Mii will find a solution in the future...

 

1 hour ago, C50 said:

Wow, you're GPS crazy lol!

 

I don't understand. I haven't said anything about GPS, have I?

No nothing.  I am the guilty one. 

I like to know where i am going, where i have been and that goes for in a car as well.

 

Roads are the same distances as they were when i started on a moped at 16 year old if they have not be altered, and i remember the distance between every town or village and the 

fuel economy of everything i own or buy the fuel for.  It passes the time when travelling if not listening to the radio.

 

GPS on the Phone or Wrist is handy now, set to bleep every mile and for a few miles compare with the Odometer ticking over the miles.

 

 

Edited 17 August, 20187 yr by Offski

 I see.

 

I can't imagine the systems in the Citigo differ substantially from other VW group vehicles of similar vintage, so probably not that hard to figure out.

Normal. Compared to my GPS  70mph equates to 77mph on the speedo on my Roomster so I have never got caught speeding on the motorway. The 10% tolerance lessens at lower speed so at 30mph shows 33mph on my speedo.

You can correct by selecting a larger tyre diameter for your rim size. Or larger rim with width and aspect to have a larger tyre diameter.

Use willtheytfit web site