Well now, here's an interesting way to save on warranty costs and make your cars look like they're lasting longer:

http://www.usatoday.com/money/autos/...ter-usat_x.htm

I couldn't believe that the standard is really +/- 4%. So for every 100 miles driven your odometer could be as much as 4 miles over or under? In this day and age when we have all these calibrations and fantastic technology we can't count miles right? Interesting that the lawyer involved says Detroit brands are "pretty much perfect" in this regard.

 

Whoops. Another nail in coffin of the superior-foreign-car myth

 

I remember Car and Driver tested some new car speedos and odos to check for accuracy. I think all of the cars tested were within spec, and GM was almost spot-on. If only their gas gauges were as accurate.

 

That'd be nice. You just gotta learn that a 1/4 tank really means "holy sh**, get to the gas station!"

 

In this day and age with digital odometers and superior process control technology, the odometers being "fast" had to be deliberate.

Whether this was done to reduce waranty repairs is up for debate. Mathematically, it would reduce warranty costs by up to 4%. However, I would think that most warranty repairs would occur early in a car's life due to part quality glitches. Most reliability curves show an initial higher failure rate, it then stabilizes until the product starts to wear out.

I wonder if the speedometer is directly linked to the odometer on Hondas. If so, then the seedometer would read fast, as well. Could you sue Honda for too many speeding tickets.

 

Did you know that this was done deliberately? They have done studies on how people perceive the gas gauge readings.

 

I recall them discussing this as well. I think it may have been in a 10 Best issue, unless they did a separate standalone test that I'm forgetting.

I seem to recall the BMW odos being pretty far off, too.

 

I read a couple of places that the 4% over thing is the extreme case and that the average inaccuracy was about 1.5% to Honda's benefit, which is really not that extreme, though if deliberate would **** me off, I suppose it could also have been an oversite in some standard calibration for their odometers, transmissions, or some computer component shared between many of their models?

I checked my Lexus a few times again those highway mileage markers and found I actually experienced the reverse effect. If it said I had gone 100 miles on my odometer, according to the mileage markers I had actually gone about 101.5 miles.

No, because if your speedo said you were doing 50, you'd actually be doing 48... so in fact you'd get fewer tickets.

 

irt the BMW speedometer inaccuracy thing, I think thats from a C&D article, and it was Germans in general, with BMW being the worst offender, reading something like 9mph off. this was several years ago, though

 

Twas a long time ago. Of course, in the 80s, Ferrari and Lamborghini speedometers were frequently off by 10-15%.

But today, in the era of electronic controls? Inexcusable. As is a gas gauge designed to diddle the results to make it "look" better.

It seems that less of the gas gauge fudging is going on today, though--our newer cars (2000+) seem much more linear than the "oh, crap, get to the gas station NOW" on 1/4 tank experience that the fourth gen F-bodies gave you.

 

I believe it has a lot to do with tire diameters, a fresh tire is about an inch larger in diameter than a worn one, +/- 4% tire tread wear....over time it all adds up.
And not every tire maker's tires are the exact same size, even with identical size labeling.

 

My truck went from 13k to 15k back to 13.5k because the dealer had to replace the DIC twice. Makes me really trust modern ODO's.

 

My G6 always reads slower than I'm actually travelling as verified by my GPS.

 

I think the only deliberate thing about it is that they stay on Full for the first 100 miles so it looks like the car gets great gas mileage, as in "Look Martha, we've driven 100 miles and the tank is still full! This car must be great on gas". GM gauges have been this way for as long as I can remember, while almost every other automaker is more linear.

 

200 miles on the 1st half tank, 20 on the second.