[QUOTE]Originally posted by 21wS2K
[B]

So then it is the fact that a tire's diameter expands with increase in acceleration that throws the speedometer off?

 

so then are you speculating/stating that the change in diameter is miniscule enough that everyone's accusations about the speedometer at a steady reading (since we know that the digital has a lag) being a misleading reading is incorrect and that it is closer to a justified reading?

 

That's just what I was thinking (but without the run on sentence), 21wS2K...

I have a speed trap in my town with a police radar gun and huge current speed readout. It always says that I'm going 1-2 MPH faster than my speedo... All I'm saying is that I don't understand why the digital speedo would be wrong -- or more to the point, why would it start compounding error (reading more than actual) as speed increases.

 

Not saying that at all. I am merely saying that tire expansion is not a problem. In my 50+ years of driving I have checked a lot of speedometers and I have NEVER seen one that's accurate. Most of them read on the high side, some by a lot. It seems that the manufacturers make them that way, either to exaggerate what people compute as gas mileage, or to make sure you can't sue them if you get a ticket or what. They are just not accurate, digital or analog. I have checked my S2000 many times and it reads 4 mph high at 80. Also, even if manufacturers made them dead on they wouldn't stay that way as they would be 2-3% off when tires were worn down. My Miata is 6 mph high at 80. SDurprisingly, my 02 Avalon is 2 mph LOW at 80.

 

155MPH ON THE SPEEDO

 

I saw an article in C&D a while back that talked about the speedo anomalies. And it mentioned that cars in europe have DIFFERENT discrepancies than cars inthe US. It further explained that no matter what happens to the car in europe that the indicated speed must not go below the actual speed. So auto makers adjust their speedo reading accordingly.

Here is a link to the C&D article


http://www.caranddriver.com/xp/Caranddrive...rds=speedometer

-Spoon

 

I've done 258km/h (153mph) with top down.

But i have a friend with a movie made by him (camera in the car), he has a stock S2000

 

I have tried to download this video many times but it never works for me. Could someone tell me why?

 

I've tried to find it in one of the computers I have but of no avail. The car in the video hit 283KPH briefly (I'm a TV editor and I have a photographic memory) or about 175mph.

It's in the archives, because I remeber commenting about the jerk with the F-40 video doing over 200mph in England, or Sweden and he lost his license because the prosecutors used the video as evidence against him and I warned this other guy about it --- so that may be why you can't find it!!!

 

Not that I question the accuracy of some of the 160 MPH claims but I can't help but wonder how some in here can get their S2000 up to 160 MPH when a fairly heavily modified S2000(over 300hp claimed) could only get into the high 150's at the Bonneville Salt Flats?