Funny thing I noticed driving on the by-pass loop tonite.

My digital readout is anywhere from 1 - 2 mph higher than my speedo and its needle. Anybody else notice this on their car.
The dealer, of course, tells me not to worry and to go by the digital which I don't have selected as my default settings.

Thanx for the feedback.

P.S.
I know that they both use the same pickup but are processed independently.

 

I have a one mph disagreement also. I don't remember which way it is. I never use the digital speedometer.

 

Since 1 MPH is the minimum resolution of both meters 1 MPH is darn good. You will probably find that the digital is more accurate.

I calibrated mine 5 ways at 50:
Analog Speedo
Digital Speedo
ODBII Scanner
Police Radar Display
GPS

Then I calibrated 4 ways at 100
Analog Speedo
Digital Speedo
ODBII Scanner
GPS

All were same except Analog was 1/2 to 1mph off, but repeatable.


Your tires will make some difference.

 

So I got new wheels and tires and according to an online calculator it should make 2-3mph different from my stock tires/wheels. Does the digital speedo compensate for this or not? Thanks.

 

The digital readout is more likely to be accurate. There is some law about speedometers I read about last year. The regular speedo has to read slightly above the actual speed, I guess because differences in tire pressure could make it read below actual speed. And this is not allowed. I guess there must be no chance of it ever going below the actual speed.

But trip computers can be dead on accurate, and usually are pretty close. I guess the digital readout is allowed the same.

 

My analog gauge and digital speedometers are in perfect sync, at least at normal traffic speeds (5-80mph). I have even pointed this out to friends to illustrate the "precision" of German engineering. But after reading this, perhaps I should conclude I'm just lucky.

 

I was cruising at 120 last night and the analog said 120 and digital said 119. close enough for me.

For those of you that have ever driving at those speed for a sustained time, a minute or more, is it just me or do you go into a "zone" like sly stallon did in driven? I did

 

mine are in perfect sync also

TimmyC230boy, i think you meant that the digital read 119 not 199

 

Fixed Thanks
Tim

 

Naw, it's 199. He was in his "zone." LOL!

EDIT: Aw shucks, Timmy, you took away my dream and changed it. And I was having so much fun, too!

 

Officer: Sir, do you know how fast you were going?

Driver: 190? 195?

Officer: Sir, you were going 52 in a 45 zone.

 

Really, Officer? (As he looks at the $50 bill in his hand). Um, are you sure it wasn't 195?

Some of those NASCAR TV ads are pretty cute...

 

*hands the officer a $20*

Driver: Are you sure it wasn't 190? *wink*

 

LOL, great minds think alike.

 

UMMM hate to say but the fact that your analog and digital speedo read pretty much the same (1mph) could mean that the digital is reading off the same thing as the analog and not seperate signal/sensor. B/C when I got the rims/tire changed the two speedo still read the same (even though my actually speed is supposed to be about 3mph off) which mean the digital speedo is just a gimicky display to fill up on the menu. If they DO read different signals then my digital should display a different speed then the analog.

*I've seen the Gumball3000 clips of Ruf Turbo doing about 200+mph on digital readout and its diff from the analog indicating diff. signal read (accurate)

 

I too remember reading an article about this. It said that most manufactures calibrate the speedometer higher than the actual speed. They even compared the difference between car manufactures.

 

Yes i vaguely rem this article as well and surprisingly the American auto manf. (GM I believe) were the most accurate (or should I say closest to actual speed).

 

It was in either Car and Driver or Motor Trend. I get both of those. And I think they all do it, because it is the law. They have to be a certain percentage over or something. Maybe I can find the article one of these days.

 

the analog speedo has about 4% of difference at 70 mph for MB. BMW has almost 7% difference, and VW/Audi has about only 2%.

the last time i was driving at the 155 limit. the analog shows close to 160.

 

After moving from stock 17" C7s to 18" Moda R6s I recalibrated the tire size in COMAND (size plus tread depth).

Anyone know, does this calibrate (adjust algorithms for) the speedo displays.

After switching it seemed like my system computed gas mileage as lower but this was just an impression and I have no data to substantiate it.

 

Lucky for you guys with the matching set.

I think I'm going to find me a nice cop, one that likes to do community service and not one that tries to sublement his income, and ask him if he wouldn't mind helping me out.

And you "CANNONBALLERS", you know who you are.... can I borrow your '*****' some times? Driving this fast on american highways which aren't built for these speeds, with little ole ladies doing 40 down the center lane...... LOL

 

The only way I can do it in a car now was from all of the life-threatening situations I made it through for years on a motorcycle.

You learn to realy be aware of what other people are doing when you got nothing between you and them but Levis ;-)

 

Hey, I got no problem driving on the Autobahn. Take out Sissy's car once a year. What scares me are the peolple over here who only pay attention only to whats in front of them, NOT beside them, NOT behind them or think they own the road, doing below the speed limit and/or conditions, and think they are IT and everybody else better toe the line. Now that is scrary.

 

No, that does not calibrate the speedo. the calibration on the command system is for the accuracy of the navigation.

 

Ok, that makes sense.

BTW, just a side note, I checked and my analog/digital speeds are reading spot on the same. Wether they are both my actual speed or not is another question.

But then, larger circumferance tires would make my car think it is moving slower, MPH wize, wouldn't it?

So my milage would read lower then actual as would my speed, no?

Ahhh f it. Just step on the pedal ;-)