What is correct, Speedo or sat nav?

Strider590

iolanthe07 wrote: »

I guess the german manufactures can be bothered to calibrate their speedos properly.

That's because some of them with in-built sat navs can't be bothered to modify their kit to allow a 6 digit UK post code.

Doesn't matter if it wears a BMW, Mercedes or Audi badge.... Most Brits don't buy those brands for their technical qualifications, they buy them because they want to look middle class. Stretching those 8 credit cards is easier than gaining a professional qualification and getting a well paid job

jase1

I have quite high level academic and professional qualifications, and a relatively well paid job (c80k/year) and I still drive around in a 4 year old Focus bought from a shed

Strider590

jase1 wrote: »

I have quite high level academic and professional qualifications, and a relatively well paid job (c950k/year) and I still drive around in a 4 year old Focus bought from a shed

Exactamundo (I think that's an American word)..... Tis those who don't have money who insist most on appearing as if they do.

Risking getting into a rant about the British class system, consumerism and Zeitgeist.... lol

adouglasmhor

C_Mababejive wrote: »

Indeed though the prescribed and supplied apparatus for such measurement is the vehicle speedometer and so it is to that which we should give greater credence and it suffers much less hysteresis than a sat nav

Traffic police speedos are set up to measure accurately, not the ones in our cars.

birkee

missile wrote: »

The police are interested in your speed not how you measure it.

Let them identify you as having a non working speedo then.

United Kingdom

The amended Road Vehicles (Construction and Use) Regulations 1986 permits the use of speedometers that meet either the requirements of EC Council Directive 75/443 (as amended by Directive 97/39) or UNECE Regulation 39.[11]
The Motor Vehicles (Approval) Regulations 2001[12] permits single vehicles to be approved. As with the UNECE regulation and the EC Directives, the speedometer must never show an indicated speed less than the actual speed. However it differs slightly from them in specifying that for all actual speeds between 25 mph and 70 mph (or the vehicles' maximum speed if it is lower than this), the indicated speed must not exceed 110% of the actual speed, plus 6.25 mph.
For example, if the vehicle is actually travelling at 50 mph, the speedometer must not show more than 61.25 mph or less than 50 mph

adouglasmhor

Missing the point there a bit Birkee, yes you need to have an operational speedo, guess what, your sat nav counts, one of my motorcycles had a radar speedometer that counted too, no one is saying you don't legally need a speedo, just that is not the speed reading they will use to prosecute if you exceed the limits.

leosayer

Flyboy152 wrote: »

Manufacturers do not deliberately set the speedometer incorrectly.

They don't, but they have to make allowances for the different size tyres which could be fitted to the car.

It's not unusual for there to be a 2-3% difference in circumference from one wheel/tyre size to another for the same model car.

birkee

adouglasmhor wrote: »

Missing the point there a bit Birkee, yes you need to have an operational speedo, guess what, your sat nav counts, one of my motorcycles had a radar speedometer that counted too, no one is saying you don't legally need a speedo, just that is not the speed reading they will use to prosecute if you exceed the limits.

Without going through all the regs myself, have YOU read them? If it says speedometer, it means speedometer. Radar type or otherwise.
Do the regs mention alternative means as being acceptable?
Do the regs mention the accuracy required by other means of indication?
How can sat nav be used to overcome the regulations?

When I was a kid, I got stopped by the Police riding a Corgi (never mind....little thing originally designed for paratroops) They were not happy with me not having a speedo, but in those days, if the vehicle couldn't exceed 30mph, you didn't need one. THEY didn't know THAT law.

spugzbunny

My speedo is allways around 4mph faster than the SatNav at 70. So yes - in the 5-10% overread bracket.

adouglasmhor

birkee wrote: »

Without going through all the regs myself, have YOU read them? If it says speedometer, it means speedometer. Radar type or otherwise.
Do the regs mention alternative means as being acceptable?
Do the regs mention the accuracy required by other means of indication?
How can sat nav be used to overcome the regulations?

When I was a kid, I got stopped by the Police riding a Corgi (never mind....little thing originally designed for paratroops) They were not happy with me not having a speedo, but in those days, if the vehicle couldn't exceed 30mph, you didn't need one. THEY didn't know THAT law.

#
There is a speedometer on your satnav, It is a meter the measures speed (and displays it) and that is what speedometer means (a bit obvious really) so you are covered as long as you are getting a signal and in the accuracy level (which you will be) they may be able to get you in a road tunnel though I suppose.
Corgis were a great bit of kit, 98c two stroke no gears, wee wheels no suspension.