While I believe there was some discussion about this quite some time ago, I want to bring it forward again now that I've purchased and am experiencing what I believe is a significant mis-read issue with the speedometer.

Got the G about 3 weeks back, but after the excitement/distraction of the first week, I started to notice that while I was driving the same stretch of highway at the "same speed" that I've driven for years, I was getting passed by ~75% of the cars on the road. In former vehicles I would have been running with at least the upper ~25% or more of the cars when running at that same speed.

Based on 'gut feel', I've been suspecting the speedo was reading quite high, but confirmed it on a run with two other friends yesterday as I used the cell phone car to car to car to verify what they were reading. Where I was reading 120 km/h, they were reading 109km/h and 111 km/h respectively.

That's an average 10 km/h difference at those speeds - a serious difference and major issue in terms of confidence regarding accuracy and $$ regarding tickets.

Interestingly, when I hit some small towns and had to drop speed because the limit was 60 km/h, I stuck right to the limit (according to the speedo) and my friends said I was within 2-3 km/h of what they were reading. So apparently the higher you run, the broader the disparity.

This variance is a major pain from both a potential ticket and 'enjoyment' perspecitve and I wanted to check-in with other new G drivers to see if they're experiencing the same feeling/reality? And if so, just how do we go about recalibrating? Can a dealer do it?

Any similar experiences. Thoughts/suggestions?

 

I tested mine, it's accurate within 1 mph or so at 70.

 

Are your tires inflated to the correct psi?

 

Good question - sorry, should have added further detail to eliminate a few possiblilities: Yes, tires are at the right psi, and wheel size/tire type are stock.

 

I am within 1 mile below... and I went up as fast as 100 mph whereas it was really 99mph based on my Garmin Nuvi.s read from satellite.

 

Yes my car is the same as yours at 120 on the speedo my real speed is 113.
I have winters on in the same size as stock but there is a slight difference in overall diameter even though manufacturer sizing is the same. This difference is not enough to account for the amount of speedo error that I have.

Here are my test results with my GPS from my other post:

Speedometer Reading.................Actual reading(GPS)
80 km/h (49.7 mph).....................75 km/h (46.6 mph)
100 km/h (62.1 mph)................... 94 km/h (58.4 mph)
120 km/h (74.56 mph)..................113 km/h (70.2 mph)

Here is the other post that discusses this topic: https://g35driver.com/forums/showthr...ht=speedometer.

 

I suspect the car is dead-on accurate, I question the accuracy of the metric system in general, it's a fad. As long as beer is ordered by the pint, no one's going to adopt the metric system

Score: Metric System 0, Imperial System 1.

Imperial system is so easy, 1 gallon = 1 gallon of gas, not 4.546 litres... I'll stick with my Pecks, stones, tons, bushels and furlongs.

 

Hey, My car's speedo has both, doesn't yours?

 

LOL, do you still rub two sticks together to make a fire for dinner in or outside of your cave?

 

ROFLMAO

 

You do realize that the majority of places in the world use the metric system right?

 

I was going to ask about clubs and spears but thought that might be going too far

 

My car is speed-limited to 492,800 cubits per hour...

 

Take your car back to the dealer and have them fix it. If your tires are stock and inflated and your car it not reading the correct speed it's Infiniti's problem not the metrics systems.

BTW, as I've said before it still odd that some things have a mixture of measurements, i.e. tires (245mm / 45% and 18 inches).

I live in the U.S. and prefer inches, feet, yards, miles, quarts, gallons, etc. But that only because it's what we use. One is really not better than the other, they are just different. Let's not start a U.S. vs. Canada debate. Our friends to the north might start shooting their muskets at us.... Awww, I'm only kidding, I kid.

 

Before going much further you should check your speedometer the old fashion way; timed over a measured distance. There are still locations here in the US that have "measured" miles along the Interstates for this purpose. Using our obsolete but adequated system of measures, a measured mile at 60 miles per hour takes exactly 1 minute.

I think GPS is a wonderful invention, but question its accuracy for checking speedometers.