Warranty ran out

Flyboy152

visidigi wrote: »

Why can't a speedo under read but it can over read? Thats not common sense, thats assumption!

The speedo shows a speed, now that speed it displays might be 5 miles an hour above the physical actual speed.

But the speedo and the mileage are not directly linked - the mileage is calibrated by the manufacturer based on the rolling circumference of the wheel itself, so the speed shown does not affect the milage measured.

Just because it says I am doing 70 miles an hour does not mean I cover 70 miles, I cover the distance related to the actual speed.

Therefore the mileage shown is accurate...

I am not quite sure you have thought that through.

Flyboy152

Jakg wrote: »

On my car the over-read is done in software - the car knows exactly how fast it's going to accurately record speed / MPG / distance travelled - but for display on the speedo an over-read is added. If you drive along for a certain distance at a certain speed you'll notice you haven't travelled quite as far as you should of done...

Sorry, but that doesn't make any sense. Who or what adds this overread?

bod1467

Flyboy152 wrote: »

There is absolutely no evidence anywhere which states that speedometers and odometers overread by at least three per cent.

http://www.publications.parliament.uk/pa/ld200001/ldhansrd/vo010312/text/10312w01.htm

Speedometer Accuracy

Lord Allen of Abbeydale asked Her Majesty's Government:

Whether, in the light of the increasing importance of speed limits, they have any plans to make it easier for the private motorist to have his speedometer tested for accuracy.[HL839]

Lord Whitty: 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.

A vehicle meeting these requirements would not be able to travel at a greater speed than that shown on the speedometer and a driver could not, therefore, inadvertently exceed speed restrictions. Her Majesty's Government have no plans to introduce instrument tests

Flyboy152

I don't see the point.

bod1467

Don't see the point in what?

Seems eminently clear to me - you made a statement, I disproved that statement.

Flyboy152

bod1467 wrote: »

Don't see the point in what?

Seems eminently clear to me - you made a statement, I disproved that statement.

Where have you disproved the statement?

There is absolutely no evidence anywhere which states that speedometers and odometers overread by at least three per cent

bod1467

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

That's where. Can't get any better than legislation.

In reality, manufacturers tend to use a targeted overstated reading then apply +/- tolerance on that, as trying to achieve a specific -0% tolerance is prohibitively expensive. (Cite: lots of online resources, such as http://www.speed-trap.co.uk/Accused_Home/Rules_useage/The_Law.htm)

I know you'll nitpick this response, but I guess some people just HAVE to prove themselves right, even when they're wrong.

Jakg

Zandoni wrote: »

I'm not saying you are not correct, who knows what they can do now with the on board computers. But I do wonder if you can actually notice it, you would have to travel a long distance at a constant speed to be able to check it.

Not really - my car has an average speed on the trip computer.

Other owners have reported setting the cruise at 80 gives a constant 80 speed on the speedo, but it records it as an average of 75...

Zandoni

Jakg wrote: »

Not really - my car has an average speed on the trip computer.

Other owners have reported setting the cruise at 80 gives a constant 80 speed on the speedo, but it records it as an average of 75...

Doubt that proves the mileage is accurate when the speed isn't.

bod1467, have you changed sides?

Flyboy152

bod1467 wrote: »

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

That's where. Can't get any better than legislation.

In reality, manufacturers tend to use a targeted overstated reading then apply +/- tolerance on that, as trying to achieve a specific -0% tolerance is prohibitively expensive. (Cite: lots of online resources, such as http://www.speed-trap.co.uk/Accused_Home/Rules_useage/The_Law.htm)

I know you'll nitpick this response, but I guess some people just HAVE to prove themselves right, even when they're wrong.

But that still doesn't mean that there is any evidence to show that all speedometers are set to overread by at least three per cent, as implied by Zandoni. We all know that there are tolerances allowed by manufacturers, in accordance with the regulations, but if they were set to overread by three per cent, that would imply they have already calibrated them to 0%. Becasue that value will have to be determined, before working out what the three per cent is.