What's been the fastest speed you've driven so far, in a car ?

Hachiroku ãƒ�ãƒ�ãƒ*ク wrote:
> On Thu, 03 Sep 2009 20:20:51 +0100, DavidR wrote:
>
>> Depends how you define error. Is it due to speedometer manufacturer's
>> tolerances or a deliberate offset specified by the car manufacturer? I would
>> guess they are manufactured with a 2% spread and the "error" is deliberate.
>>
>> Why is an offset a problem for you?
>>
>> It wouldn't make any difference whatsoever to accuracy (other than lag under
>> acceleration/braking) whether the speedo was designed to accept one pulse
>> per 100 wheel revolutions or 100 pulses per wheel revolution. Whatever is
>> current practice, it is perfectly sufficient.
>
>
> In my case, 116/122=0.950819672. That's a 9.5% error, and is 'acceptable'
> by LEAs and maunfacturers.
>
>

Actually, the % error is 4.9%. The 2 problems above a

1) percentage is a movement of 2 decimal places, not 1; and

2) percentage error is the error (i.e. the difference between the 2
values) divided by the actual value, not the indicated value divided by
the actual value.

The value you calculated was the '% correct'.

--Andy

"Boltar" > wrote
> On Thu, 3 Sep 2009 20:20:51 +0100
> "DavidR" > wrote:

>>Depends how you define error. Is it due to speedometer manufacturer's
>>tolerances or a deliberate offset specified by the car manufacturer? I
>>would
>>guess they are manufactured with a 2% spread and the "error" is
>>deliberate.
>>
>>Why is an offset a problem for you?
>
> Is this a trick question? You might as well ask why I need to know my
> speed at all. If you're going to have a speedo it helps if it tells
> you your actual speed , not some rough approximation. If the speed
> limit's 70 I want to know when I'm doing 70 , not wonder if I'm doing
> 70 or 62.

It's easy. If the speedo indicates 70, you're doing less than 70. If it's
such a problem to you, if you have a satnav/gps why don't you check the
error? If you offer money (*) a dealer might even be able to plug in the
diagnostic and adjust it for you - which I guess they do if the speedo has
to be changed, because it's probably delivered "dumb" and has to be
personalised to the wheel/tyre combo.

(*) Ah, there had to be a catch. Most of us can cope with the "error"

>>current practice, it is perfectly sufficient.
>
> Says who? You? Clearly something isn't sufficient or they wouldn't be
> so inaccurate.

Then you clearly don't understand how it the device works. Simply put, the
"inaccuracy" has nothing to do with the method of sensing.

On Fri, 4 Sep 2009 23:56:18 +0100
"DavidR" > wrote:
>It's easy. If the speedo indicates 70, you're doing less than 70. If it's
>such a problem to you, if you have a satnav/gps why don't you check the
>error? If you offer money (*) a dealer might even be able to plug in the

Well I don't have satnav (some of us can read maps) and I'm not going
to buy one to check something which the car should tell for me.

>(*) Ah, there had to be a catch. Most of us can cope with the "error"

Oh right, so I guess you don't care if your rev counter, engine temp
gauge or radio frequency display give the wrong information too? I
mean who cares if the radio says 94.9 when you actual want Capital on
95.8? You can just listen for the jingles right?

****.

>> Says who? You? Clearly something isn't sufficient or they wouldn't be
>> so inaccurate.
>
>Then you clearly don't understand how it the device works. Simply put, the
>"inaccuracy" has nothing to do with the method of sensing.

Odometers have to be accurate - I doubt a 15% discrepancy in the
mileage would be acceptable - and since that gets its distance info
from the same place as the speedo....

As for wheel/tyre/pressure arguments, they're just straw men. A speedo
should be 100% accurate when the car is running on the wheels and tyre
sizes it was sold with and the tyres are inflated to manufacturers
spec.

B2003

70 MPH is Super Fast for me.I prefer the back roads where I can slow
poke along at 30 and 40 MPH.I can even do 25 MPH on some of the back
roads when I have to go shopping.You couldn't pay me enough money to get
on the high speed roads and interstates nowadays.
cuhulin

On Sat, 05 Sep 2009 05:08:31 -0700, Boltar wrote:

>
> On Fri, 4 Sep 2009 23:56:18 +0100
> "DavidR" > wrote:
>>It's easy. If the speedo indicates 70, you're doing less than 70. If it's
>>such a problem to you, if you have a satnav/gps why don't you check the
>>error? If you offer money (*) a dealer might even be able to plug in the
>
> Well I don't have satnav (some of us can read maps) and I'm not going
> to buy one to check something which the car should tell for me.

I finally got one a few weeks ago.

I am a factory service rep for a main computer mfgr and travel a lot of
central New England. I would print out maps from Mapquest and use them,
and then I got GPS through my cell phone. Screw the maps! I don't want to
stop to look at a map, and I have the GPS set up on the dash like a HUD.
The phone GPS cost $10 a month, so I bought a TomTom on eBay for $45 and I
can't imagine why I went so long without one!

Of course, if this position ends or I get another office job, I'll
probably put the GPS back on eBay. It is kind of a toy if you have no real
use for one.That's why, even being the gadget freak I am, I never bought
one until now.

BTW, my Supra has a busted speedo, and after I turned on the MPH function
on the GPS I now know what speed I'm driving.

On Sat, 05 Sep 2009 08:21:29 -0500, cuhulin wrote:

> 70 MPH is Super Fast for me.I prefer the back roads where I can slow
> poke along at 30 and 40 MPH.I can even do 25 MPH on some of the back
> roads when I have to go shopping.You couldn't pay me enough money to get
> on the high speed roads and interstates nowadays.
> cuhulin

Let's see...Pickup truck?
Hat?
Speed inversely proportional to number of dogs in the car/truck?

I think you're a wee bit older than I am, and have to say, if you're
driving safely, you're to be commended!

"Boltar" > wrote in message news:0a9e5506-a118-48c5->
"DavidR" > wrote:

>>It's easy. If the speedo indicates 70, you're doing less than 70. If it's
>>such a problem to you, if you have a satnav/gps why don't you check the
>>error? If you offer money (*) a dealer might even be able to plug in the
>
> Well I don't have satnav (some of us can read maps) and I'm not going
> to buy one to check something which the car should tell for me.

I don't have a satnav either. But you must have a clock? Every motorway has
markers every 100m. It's simple timing & maths. (Just make sure you are the
passenger seat when you do it.)

>>(*) Ah, there had to be a catch. Most of us can cope with the "error"
>
> Oh right, so I guess you don't care if your rev counter, engine temp
> gauge or radio frequency display give the wrong information too?

For temperature, it's patterns of behaviour that matter, not numbers. For
revs, there are two extreme values and the position of the needle indicates
proportions between; numbers also don't matter (in jet engines they are
simply marked to 100%)

> I
> mean who cares if the radio says 94.9 when you actual want Capital on
> 95.8? You can just listen for the jingles right?

Have you not seen a radio with an analogue dial?

> ****.

Why the need for abuse? I can only assume that you have no concept of the
technicalities and you're just ranting.

>>> Says who? You? Clearly something isn't sufficient or they wouldn't be
>>> so inaccurate.
>>
>>Then you clearly don't understand how it the device works. Simply put, the
>>"inaccuracy" has nothing to do with the method of sensing.
>
> Odometers have to be accurate - I doubt a 15% discrepancy in the
> mileage would be acceptable - and since that gets its distance info
> from the same place as the speedo....

Exactly. So, you must assume the main "error" occurs between the needle and
the numbers on speedo face, not the measuring process, ie, there's a
deliberate offset.

> As for wheel/tyre/pressure arguments, they're just straw men. A speedo
> should be 100% accurate

A 100% accurate speed indication is scientifically impossible (let alone
technically).

My old 1978 Dodge van has a speedometer which reads in MPH and KPH.My
1983 Dodge van speedometer reads only in MPH.
cuhulin

On Sep 6, 9:25*am, "Jeff Strickland" > wrote:
> "Hachiroku ????" > wrote in message
>
> news >
> > On Sun, 06 Sep 2009 12:13:02 +1000, Toby Ponsenby wrote:
>
> >> Natch, the only way you can avoid these stupidities is to ride a bicycle.
> >> They are NOT legislated to carry a speedometer,
>
> > SHHHHHH!!!! Don't give them MORE ideas!
>
> > However, you can be cited for riding under the influence! *
>
> I was stopped on my bike for speeding on base. I was stationed at Nellis
> AFB, outside of Las Vegas, and rode my bike from the barracks to the duty
> station -- I had a car too, but the distance was short, the pay was low, and
> gas was rationed in those days. Anyhow, the speed limit on base was 25 in
> most areas, and 35 in areas where it was not 25. I was pulled over by the
> MPs for exceeding the 25mph speed limit. They paced me, and cited me for
> flying under the radar.
>
> I don't remember getting a ticket, but a speeding ticket on a bicycle is not
> outside the realm of possibility. The lack of a speedometer is not a
> defense, as far as I know.


In 1999 or 2000, in the City of Davis, California, while I was at the
University of California at Davis, I was stopped by a bike cop for
biking on the wrong side of the street, and got a $30 ticket.

Michael