I recently tok a nice road trip in the SS. We had a magellan GPS with up that had a speedometer in it.
No mater what speed i was doing the GPS was always 3 mph faster or i was 3 mph slower. The reason i ask if my speedo is of is becasue i also constantly see a 3 mph difference whenever i drive next to a new Civic. (They have a digital speedo so you can see it from outside the car.)
Has anyone else noticed this?

 

Do you have stock rims and tires? If not that could be the reason why.

 

Oh yeah i forgot to mention. I am stock with everything. Wheels and tires included.

 

3mph is so minimal, i dont think it really matter, gps cant really give you an exact number, just a very good estimate. and on the other hand, the honda is built differently and calibrated differently then the ss/sc. They may just be how everyones is.

 

That's very interesting...difference is usually proportional to your speed (the faster you're going, the more it's off). To see it off by exactly 3 mph at any given speed is indeed a puzzler.

One way to check, assuming you're still on the stock wheel/tire, is to take it to check your tach in any given gear. 2nd is about 10.5 mph / 1000 rpm, and 3rd is just a fraction over 15. (68 mph @ stock redline in 2nd, 100 in 3rd)

For instance, if you're in 2nd at 2000 rpm, you're going 21 mph. Which ever readout confirms that is the right one.

 

I posted this same thing a while back. I have an 06 with the latest flash and I figured I'm about 4% off. My speedo reads higher than actual though. At 75 mph, other cars speedos are at 71 or 72. I figured this out by mileage too. This was over a 1200 mile round trip so I know it was off. I took it in to have them check it but all they did was hook up the tech 2 and said it read the same as the speedo which i knew it would. The computer flash is inaccurate in my opinion.

 

the radars around here always read me at 3mph off. I'm usually going 3mph slower than my speedo says.

 

3mph is actually alot living in a town where my friend got pulled of for driving 26 in a 25 and threatened with a ticket for about 5 minutes.

-Rich

 

Definitely better to have the speedo read high than low for ticket purposes. At this point, its a buffer zone for me even though I know its off a bit.

 

That is about normal, I have stock wheels and tires. There is a radar sign in my neighborhood and everytime it flashes for the speed limit I look down and mine will read read +2mph

 

i dont know if mine is off or not, but i know when i turn my car off the gauges all go below the zeros and bounce back and forth for about 3 seconds, and then they stay all the way down past the zeros until i turn the car back on, is this normal as well?

 

my car shows +3 mph on the speedo when sitting still as long as the engine is running......

 

My speedo is always 3 mph faster than the number radar speed signs give me , this happens on about 3 different signs in my area.

 

I ran to a neighboring city yesterday and today, and took my GPSMap76 from my SeaDoo with me. It shows i'm about 4 Kph out at 100 Kph (4%). The radar guns around winnipegs construction site confirmed my GPS readings. And i'm totally stock. (Except for PIAA Superwhite fog lights )

 

mine reads 75 when the speed signs on the roadway read 72

 

I have the garmin and Im always 3 mph faster, but in my 97 ford f150 truck im even, my GMC 3500 van 3mph over, my moms Pacifica even, My new 06 2500 silverado "work truck" 3mhp over
so i figured GM makes us think that we are goin fast but reallife we are actually 3mhp slower
not that it makes a diff, but we are slower then we think...

 

this sounds funny but never notice that, Ima take a look this morning

 

My 91 Caprice is dead on, except when i put the 10% larger summer tires back on. Then its off 10%. *Surprise!*
My brothers 03 Alero is dead on. Dad's 86 Caprice and 01 Silhoutte are both dead on. Dads 72 pickup is off though... (again tire size issue)

 

Yeah, all those car I tested it my self, my brother inlaws avalanche also has that 3mph+ problem so, May be its the newer cars of something, why would i lie?

 

Could it be different types of speed sensors. A digital speedsensor could be more accurate because a needle simply points to an approximate speed where as the digital read out is telling the exact speed in which the car is traveling. (according to the pcm and speed sensor)

I'd say its just the difference between the mechanical and digital gauges.

 

differance is in the calibration not the differant types of guages

 

So just about everyone is showing +3 mph on their gauges.

 

Mine is accurate.

 

My speedo is off by exactly 10 mph. it is slow. any ideas?

 

Holy old bump