A thought comes to mind about the off duty Canadian officer mentioned above. I assume he was not in a marked police vehicle, and obviously not on Govt. business. What made him above the law? If he were following the speeder long enough to nail his speed with GPS, wouldn't he have had to be speeding also? What would the liability issues be if something happened during this "high speed pursuit"?
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My speedometer is 5mph off!
- Thread starter nsxrock
- Start date
My speedo, as well a clients, were both just under 5% optimistic when radar tested by a police friend. There is no adjustability built in to the system (dealer can't fix it,and it is within acura specs). Now that I run 225/45-16 and 255/40-17 it is almost dead on.
[This message has been edited by mandrewz (edited 03 August 2002).]
[This message has been edited by mandrewz (edited 03 August 2002).]
Remember, tire wear, all by itself, can account for up to 2 percent variation.
are the speedomoter and odometer connected?
in other words, if i travel at a constant 80mph, then my odometer
should read 80 miles more after one hour, right?
i'm also having inaccuracies in my Integra. reads higher than it really is.
in other words, if i travel at a constant 80mph, then my odometer
should read 80 miles more after one hour, right?
i'm also having inaccuracies in my Integra. reads higher than it really is.
There has been a Car & Driver or Road & Track article about this.
They tried to prove the fact that car manufacturers tend to make the speedos display a faster speed than the actual speed the car is traveling at.
They conducted tests on several cars, and BMWs had the biggest discrepancies. If I remember correctly, the average discrepancies were around 5mph.
They tried to prove the fact that car manufacturers tend to make the speedos display a faster speed than the actual speed the car is traveling at.
They conducted tests on several cars, and BMWs had the biggest discrepancies. If I remember correctly, the average discrepancies were around 5mph.
resulting MPG calculations?
I have a post regarding this on another thread but I'll say it here as well. If the odometer reading is connected to the speedometer measurements, wouldn't your trip mileage be overstated?
So if you're using it to calculate your MPG number, it would actually mislead you into thinking it's higher than it really is.
I use the MPG as a number to measure if my engine is operating
normally or not... not a means to save gas, fyi.
I have a post regarding this on another thread but I'll say it here as well. If the odometer reading is connected to the speedometer measurements, wouldn't your trip mileage be overstated?
So if you're using it to calculate your MPG number, it would actually mislead you into thinking it's higher than it really is.
I use the MPG as a number to measure if my engine is operating
normally or not... not a means to save gas, fyi.
No, because the amount of speedometer error is less than many other variables, and variation in mileage from one tank to another - just from driving style - is likely to exceed any speedometer error.jbum said:
Speedometer error is typically under about 2-3 percent. And it's not constant; for example, the difference due to the amount of tread on the tire (between a new tire and a worn one) can account for 2 percent all by itself.
Mileage from one tank to another is going to vary by 2-4 mpg, which is far more than 2 percent.
nsxtasy said:
This is true. I can't confirm, but I believe the government has a 5% tolorance speedometer error for the car manufacturers. If that is true, the manufacturers are doing much better than government standards, but they still can be off by 5%. If you are within a couple of mile per hour, I don't think there is a dealer around that would swap out the speedometer for you unless you paid for it yourself. I think the error is well within the manufacturers error tolorence and that means they wont do a thing.
Different states also have different laws as to acceptable speedometer error tolorences too I think. In my state, I needed a recontruction permit for larger rims (Anything over 1.5" larger than stock rims) and according to the state recontruction law, we have a + or - 7% allowable difference in over all tire diameter from stock. At 7% you can start to get an appreciable and noticable error, but that is okay according to our state
