over-reading estimates

Hi guys,

got shot at by one of those poxy camera vans yesterday on the A303.

I think I was doing about 79mph on my speedo.

I have heard much about over-reading speedos, 10% allowance and all that stuff,

do you think my E36 speedo will be reading high?

If so what would you estimate it is out by?

anyone know what hants police are like with speeders?

Thanks.

Edited by sleeper

Also depends on "cut off" speed there nicking people for, could be 80MPH, could be 71MPH(assuming offence commited in a 70MPH "limit")

Your speedo wont be out by much at an indicated 79MPH, certainly not by 10%

 

The 303 is a nightmare now isnt it?

 

the majority of road side police vans ..have a set limit of 34mph  in a 30 zone.i know this because my freind sets the machines up [dont go mad hes not the enemy ,just has part of his job calibrating machines]..but il have to ask if hes calibrated any of the motorway ones

he usally comes in my local about 5 to 6 ish ....iam off there now ..lolololol

???   what you lot on 70 plus 10% is 77 not 71.1 to many beers for you i think.

skull wrote: ???   what you lot on 70 plus 10% is 77 not 71.1 to many beers for you i think.

Fair comment and accurate computation, but based on a flawed assumption! 

71.1 was arrived at by reducing 79mph by 10%.

Well on the news this morning they were talking about speed cameras on the M4 and they were talking about nicking people for doing 79mph or over. Your speedo will read positive although maybe by not as much as 10%. I would have thought that an indicated 79mph would be less than 75, so I really wouldn't worry. At an indicated 33mph I am only doing 30, according to the speed display sign where I work anyway.

We still haven't heard what the cops said you were doing.
As for readings being 2-4 mph out at a ton that might be so on your car but not all cars are the same.Recent road test of a jap car in a well known mag using GPS based test equipment.
:- true mph 70,80,90,100,110
speedo mph 76,86,97,108,119

As I said before 10% is the maximum tolerence for manufacturers.Prestige stuff like our cars will be more accurate,like a Merc (I know I said prestige but it's the closest I could find ) that reads 103 while travelling at 100 (72 at 70) or the Macca F1 thats 100% accurate all the way to it's vmax.Our unlucky chap could've actually been doing 79 but hasn't stated yet.
Could be worse we could all be in Oz where theres 0 tolernce above the limit

skull wrote: it would not be - 10% speedo readings are about 2-4 mph out around the 100+ unless diff wheel tyres are on the car . you could try a sat nav or speed detector to check your speedo to gps to see how accuate. mine is spot on but the missus is 4mph out.

I think it depends on what car you have. Ford speedos are notorious for over reading. My old 2 litre Sapphire would go to an indicated 135mph

Also given the number of different wheel and tyre combinations availible from the manufacturers these days, how many cars actually have 'standard' wheels?

just read today in the MCN it has the acpo regs in it so buy a copy and read it .
hope it doesnt drop on you mat good luck m8

yep 14  DAYS