[stafforr]

My EB Cooper S seems to think that it is going faster that it really is. While screeming down the expressway at an indicated 90 MPH I am passing only the slower cars in the right lane. I have been driving long enough (40 yrs) to know that the speedometer is incorrect (I estimate) by as much as 10 to 15 mph. Has anyone else noticed this error in speedo readings or are you to blinded by the need for (indicated) speed?

 

[knaone]

have you changed the width/size of your wheels? if you have the speedo may need re-calibrating to compensate?

might just in general need caplibrated?

Just an idea

David

 

[mini-is-4-me]

Did you buy the Salesperson "demo". Potential customers saying, "Sheesh, I'm only in second and we are going 55mph...this car is fast".

 

[3GGG]

Maybe its reading KPH instead of MPH!

 

[BruceK]

If you have the On Board Computer, you can "clear it" while driving a steady speed and you'll get an instantaneous average speed that will be your actual speed.

You should also know that the MINI's speedometer will be slightly off by design (but certainly not by the amount you think yours might be misreading).


I posted the info below previously, but it applies in this discussion:

An interesting article in the the April 2002 issue of Car and Driver concerning speedometer accuracy explains why European cars have speedos that read slightly low.

The article asks the question why European cars typically have speedometers that do not reflect actual vehicle speed speed as accurately as speedometers in cars from North America or Asia manufacturers (based upon years of Car and Driver test data).

The article specifically mentioned BMW and Porsche speedometers (which seems to include the MINI). Of course having a European car with a less accurate speedometer is counter-intuitive when you consider the high speed autobahn travel possible in parts of Europe.

The upshot: A certain level of inaccuracy is designed in on purpose by the manufacturer in order to meet EU regulation ECE-R39. Mostly this has to do with making sure the speedometer never underreads true speed. This is important, the EU feels, because a car owner may fit a variety of different -- usually larger -- wheel and tire combinations to a car.

Here's the real interesting tidbit: Trip Computers do not have to meet this EU regulation, so they tend to read more accurately. Meaning if your speedometer says you are going 80 mph and you maintain that speed and reset your trip computer to determine your real average speed, the Trip Computer will show the more accurate, (i.e. slightly lower), true vehicle speed. I know that on my Cooper S, 70 mph on the speedometer reads as 67.8 mph on the computer.

 

[Johnboy]

I've mentioned this before.
I have checked the indicated speedo speed against my hand-held GPS and my retro-fitted in-car navi. unit on a straight section of road.
They would appear to indicate that the speedo does over-read slightly.

I cannot remember the exact numbers, but I think it was 73mph true speed as indicated by two separate GPS linked units, vs. 80mph on the in-car speedo.

If you're lucky enough to be in the U.K, there are straight sections of carriageway with circular yellow markers placed on them.... There are sections of road used by the police to calibrate their own speedometers (or so I was told). Useful if you are trying to check the accuracy of your own!

J.

 

[mini-is-4-me]

If you're lucky enough to be in the U.K, there are straight sections of carriageway with circular yellow markers placed on them.... There are sections of road used by the police to calibrate their own speedometers (or so I was told). Useful if you are trying to check the accuracy of your own!

Hmm, in the US, these markers (ours are usually white) are used to catch speeding cars via a helicopter or airplane overhead....By timing the car from one mark to the next which is exactly one mile, they can calculate your speed without a radar gun and without you "seeing them". Then a real car down the road snags you.

 

[snoopy]

Yes most Speedos are lying to you and your government told them to do it.

Here is a list of some Standards that Speedo reading error must be with in for the car to go sale in that country.

Speed reading error:

(1) -20% / +20% (Philippines)
(2) -10% / +10% (Australia, Hong Kong, Malaysia, Singapore, Thailand)
(3) -10% / +15% (Japan, Indonesia, Korea)
(4) O < V1 - V2 < V2/10 + 4(km/h) (China) based ECE39
(5) The U.S. and Canada do not specify speed reading error.

Note the China one is based on the Eu stardard. V1 is displayed speed and V2 is the real speed.

Hope this helps

 

[Johnboy]

......V1 is displayed speed and V2 is the real speed.
..

Hmm... V2 - Isn't that an aircraft term - The part when you're going fast enough to take-off

Our distance markers are circular with red quarter-sections of pie - I think they're every quarter-mile.

We have white stripes painted about half a foot wide and about a foot and a half long across our carriageways for visual speed-timing by our police force.

We also have the usual white dashes down either side of each lane in front of Gatso speed cameras. Most prevelant under a significant number of gantries over London's M25 motorway!

Still, anything that stops people going crazy on the public highway has got to be worthwhile.... I remember a quote from an American friend of my mothers...

"Why is it, in a country where everything moves so slowly, people drive so fast!"

J.