Warranty ran out

Zandoni

visidigi wrote: »

Sorry, two things wrong - one) wikipedia is not evidence. two) you think...

Im looking for cold hard facts on this one please

If you want cold hard facts do some googling, lots of info about.

It's common sense really, a speedo can't under read as it will give drivers a get out clause with speeding fines. Also tyre wear is a consideration.

The OP doesn't seem interested so I'm not going to bother researching.

alwal0307

Zandoni wrote: »

If you want cold hard facts do some googling, lots of info about.

It's common sense really, a speedo can't under read as it will give drivers a get out clause with speeding fines. Also tyre wear is a consideration.

The OP doesn't seem interested so I'm not going to bother researching.

Sorry yes i am interested, i do understand when i'm doing 70mph on the clock Satnav say's 67mph.i work that out to 57700mls but would that stand up in court?

Zandoni

alwal0307 wrote: »

Sorry yes i am interested, i do understand when i'm doing 70mph on the clock Satnav say's 67mph.i work that out to 57700mls but would that stand up in court?

Not really sure to be honest, but I'd mention it to Chrysler and see what they say.

paddyrg

Don't forget that the satnav takes mileage on a flat plane, the mileometer has to follow the hills and contours, which are of course longer.

As an example, cut a piece of A4 paper diagonally corner to corner, you have a short, medium and long side - the satnav measures the medium side, but the tyres measure the long side, so it is not a good indicator if there is a single incline in the 60k miles!

Look at it another way - if a (technically impossible, but bear with me) road went vertically into the sky above Trafalgar Square, the satnav would register 0 miles (as you would still be above TS) no matter how far into space you went (in an idealised system, that is)

Zandoni

paddyrg wrote: »

Don't forget that the satnav takes mileage on a flat plane, the mileometer has to follow the hills and contours, which are of course longer.

As an example, cut a piece of A4 paper diagonally corner to corner, you have a short, medium and long side - the satnav measures the medium side, but the tyres measure the long side, so it is not a good indicator if there is a single incline in the 60k miles!

Look at it another way - if a (technically impossible, but bear with me) road went vertically into the sky above Trafalgar Square, the satnav would register 0 miles (as you would still be above TS) no matter how far into space you went (in an idealised system, that is)

Although perfectly true, I would say that the hills and ccontours would only make up for a small amount of the difference.

Tyre wear is certainly a big factor if anyone would like to do the maths.

visidigi

Zandoni wrote: »

If you want cold hard facts do some googling, lots of info about.

It's common sense really, a speedo can't under read as it will give drivers a get out clause with speeding fines. Also tyre wear is a consideration.

The OP doesn't seem interested so I'm not going to bother researching.

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...

bod1467

Distance travelled equates to the circumference of the tyre. Let's say the tyre is 20" (508 mm) which includes 8mm tread. For every revolution the distance travelled is Pi x d, where d = 508 mm

1 Revolution = 1,595.9 mm (let's say 1,596 mm, or 1.596 m)

When the tread wears down, say to 2 mm, then d = 502 mm. In this case:

1 revolution = 1,577 mm.

Thus for every revolution of the wheel the distance travelled may differ by 19 mm, around 3/4". In percentage terms this is less than 1.2%, and this assumes a step change in diameter. In reality the diameter change is incremental as the tread wears, thus the potential odometer error is minimal - less than 0.25% as a guesstimate, which equates to about 150 miles in 60,300 miles.

visidigi

agreed, but that is down the the maintainence of the vehicle - what I am saying is the accuracy of the milage does not change, the wear and tear of other items cause the fluctuation - not the inaccuracy of the speedo/mileage whatever you want to call it.

bod1467

I agree. I was merely proving the odometer variation suggestion was a non-issue - the mileage limit was still exceeded.

Zandoni

Well have a look at The Motor Vehicles (Approval) Regulations 2001

http://legislation.data.gov.uk/uksi/2001/25/contents/made/data.htm?wrap=true



Speed-ometers1. The vehicle shall be fitted with a speedometer capable of indicating speed in mph at uniform intervals not exceeding 20 mph at all speeds up to the maximum speed of the vehicle and capable of being read by the driver at all times of the day or night.
2. For all true speeds up to the design speed of the vehicle, the true speed shall not exceed the indicated speed.
3. For all true speeds of between 25 mph and 70 mph (or the maximum speed if lower), the difference between the indicated speed and the true speed shall not exceed—
V/10 + 6.25 mph
where V = the true speed of the vehicle in mph.


My argument assumes that the odometer is directly linked to the speedometer, I'd be interested to see any info that states it's not.