Android My Tracks speedometer calibration

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If you have an Android phone and preferably also some dash or window mount, you can use the Android My Tracks app to calibrate your speedometer. Just record the track and display the stats, which shows the speed. This said, the following are my calibration results, which are typical for Toyota cars with analog speedometers. They overindicate the speed for safety reasons. Note that in addition to My Tracks, some GPS devices also show the vehicle speed, perhaps not as accurate as My Tracks.

Code:
Actual vehicle speed Speedometer speed



35 MPH 38 MPH

45 MPH 48 MPH

55 MPH 59 MPH

65 MPH 70 MPH

75 MPH 80 MPH
 
Almost all cars over indicate by 3-5% One can easily confirm that with a GPS although an Android application can make it lot easier.

Of course, whether indicated speed on the speedometer matches the reading obtained from the vehicle speed sensor i.e. OBD-II VSS PID, is completely different matter!
 
A couple years after I bought my '06 Altima, there were some complaints filed somehow, due to the speed being off by 2+ MPH from the factory. Nissan allowed you to bring in your car for free recalibration.

That being said, speed being off by a percentage is common now. I wonder why Nissan allowed it to be recalibrated back then, but no automakers are doing anything about it these days.
 
I went from a 235/75/15XL(stock size) to a 30x9.5x15 tire a 3.9% increase in diameter,

And now my Speedo, according to gps, is right on the money.

So far that has been the only time I have used the GPS on my smartphone, though once, I did notice my battery draining faster and noticed it was turned on. Not sure how that happened.
 
Originally Posted By: kyxtremetuber
They don't over indicate for safety reasons it to get the car out our warranty faster


Thats absolutly correct. Honda intentially did this, and had to settle with the Gov't for doing so. They over calibrated their speedos 3%-5%.

Anyone who thinks its "for safety" is fooling themselves.
 
Originally Posted By: gfh77665
Originally Posted By: kyxtremetuber
They don't over indicate for safety reasons it to get the car out our warranty faster


Thats absolutly correct. Honda intentially did this, and had to settle with the Gov't for doing so. They over calibrated their speedos 3%-5%.

Anyone who thinks its "for safety" is fooling themselves.

This is actually simply false. Speedometer and odometer have entirely different calibrations, as they have independent mechanisms. Odometer is a mechanical counter, whereas the speedometer is some sort of a magnetic or spring torsion balance.

For example, in my case, the odometer overindicates by only about 2%, while the speedometer overindicates by about 7 - 8%. Speedometer calibration is for safety reasons.
 
Originally Posted By: Gokhan

This is actually simply false. ...

, the odometer overindicates by only about 2%, while the speedometer overindicates by about 7 - 8%. Speedometer calibration is for safety reasons.


Really? Let me provide something to back up what I said:

http://www.cbsnews.com/news/is-your-odometer-cheating-you/

In a class action lawsuit, Holmes charged Honda with fraud, claiming the company actually designed their odometers to run too fast.

"It shortened the warrantees, it shortened the lease contracts, it increased the lease mileage penalties that customers pay — and as a result, Honda was able to generate and save millions of dollars," Holmes said.


Thats one of many, many articles available that proves it was about WARRANTYS, not "safety".

If most all speedo's were off 8%, don't you think people would be able to tell, and most would be complaining about it?

http://www.foxnews.com/leisure/2012/05/11/how-fast-are-really-going-accuracy-speedometers/

This says BY LAW, they have to be +/- 2.5%, thats no where near the bogus 8% you claim.

Do your home work before trying to call me out.
 
Originally Posted By: gfh77665
Originally Posted By: Gokhan

This is actually simply false. ...

, the odometer overindicates by only about 2%, while the speedometer overindicates by about 7 - 8%. Speedometer calibration is for safety reasons.


Really? Let me provide something to back up what I said:

http://www.cbsnews.com/news/is-your-odometer-cheating-you/

In a class action lawsuit, Holmes charged Honda with fraud, claiming the company actually designed their odometers to run too fast.

"It shortened the warrantees, it shortened the lease contracts, it increased the lease mileage penalties that customers pay — and as a result, Honda was able to generate and save millions of dollars," Holmes said.


Thats one of many, many articles available that proves it was about WARRANTYS, not "safety".

If most all speedo's were off 8%, don't you think people would be able to tell, and most would be complaining about it?

http://www.foxnews.com/leisure/2012/05/11/how-fast-are-really-going-accuracy-speedometers/

This says BY LAW, they have to be +/- 2.5%, thats no where near the bogus 8% you claim.

Do your home work before trying to call me out.

Actually, you aren't well-informed about this.

Here is the standard speedometer calibration from the official OEM repair manual for the 1985 Toyota Corolla. As you see, the minimum standard overindication for the speedometer is +4%, and the standard overindication range is anywhere between +4% to +8% and +4% to +15%, depending on the speed. I believe this is also the case for even the newer Toyota's. Odometer is a different story:

IMAG0377.jpg
 
There different rules in different parts of the world. In the UK I believe that the basic rule is that the speedo shall never read less than actual. So to allow for errors the speedo has to set to about 5% fast as standard.
 
Besides the lease, warranty, safety issues the erroneous speedometers make the gas mileage look better than it really is.
 
Gokhan consider your source of information... it's coming from the manufacturer who is the one cheating the customer.
you're also referring all the way back to 1985, when i assume is using mechanical stuff.
from year 2000 till now it's all electronic based off the vehicle speed sensor (VSS) in the tail shaft of the transmission. That rpm, along with rear axle ratio if applicable, and tire size = speed and distance. There is no excuse if it is off by 1% or more, the only thing that would affect it is tire wear which is negligible. my 2005 altima was 4 mph fast on the speedometer at 50mph and above, but accurate at 30mph and below. accuracy based on a digital signal does not change like that, unless programmed purposely in the computer! i also verfied on straight highway i always drive, my 05 altima showed higher mileage for a given distance vs my 2002 camaro. and it always seemed like i was getting to 3000 or 5000 miles pretty quick and time for another oil change, which is what led me to looking into it.
 
Originally Posted By: Gokhan
This is actually simply false. Speedometer and odometer have entirely different calibrations, as they have independent mechanisms. Odometer is a mechanical counter, whereas the speedometer is some sort of a magnetic or spring torsion balance.

Exactly. My speedometer on my G is about 10% faster than the real speed, which I tested by radar. However, the odometer is quite on the money when it comes to odometer test strips on the road. In fact, using a ScanGauge, I can see the difference in its reported speed verses the speedometer. And, if resetting the average speed indicator while driving at a steady state, I get the proper speed shown there.

I can't speak for your vehicle, and I haven't checked out the F-150. However, Infiniti/Nissan is obviously not trying to "cheat" anyone out of warranty miles. I wouldn't call "safety" the issue either. They don't want people groaning to them when they get a speeding ticket.
wink.gif
 
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