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One of my friends got scammed by odometer reading roll back. His mechanic told him easy way to find is use your GPS and look for ur speed in GPS. IT WILL NOT MATCH with speed on your odometer. That way you can tell you odometer has been rolled back :S .. is that true ?

 
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I don't think so.

 
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so what can cause the de calibration of speedometer? i mean if your speed is different than your speedometer clearly something must have been done to your ODOMETER? and how else can one find out if it has been tampered with

 
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Did he put different size wheels/ tires on? My LX came stock with 13" tires, and I switched them out for 17". It made a pretty noticeable difference on the odometer.

Maybe I'm alone on this, but I've never heard of anybody being scammed by odometer reading roll back. Again, maybe that is just because I'm from the friendly land of Canada.

 
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Im from canada too lol. and my friend is too. He has been scammed for odometer and his mechanic told us this test to do because if your odometer gets rolled back it will be not caliberated properly. Now i noticed this in my car that my GPS tells me im going 100km/h but speedometer says 97km/h so i was thinking is there posibility its because my car has been rolled back? and no I have 15inch rims which LX comes with stock

P.s i just bought the car 3 months ago

 
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GPS readings are never 100% accurate. If you are going 100 (according to the car), but the GPS says 97, that is pretty close. I don't think you've been scammed or anything.

 
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The mechanic is an id.......False. Odometer tampering does not affect speedometer calibration or accuracy, unless the idiot doing the tampering is a total retard and screws up far more than just the odometer.


Got a particular car in mind?
On YOUR 2004, all it takes is a cluster swap to screw up the mileage. Speedo is not affected at all.



Tire diameter, gear ratios, many things-- but NOT an odometer tamper.
THIS.
If tire overall diameter is not kept the same as stock, then speedo (and consequently the odometer) accuracy is off.
I went from 15" wheels to 18" wheels, but kept my tire choice an original overall diameter so my speedo and odometer are still as accurate as the day it rolled off the assembly line.
Odometer tampering and failure to disclose known odometer inaccuracy is a federal offense.
Nope, your speedometer is exactly perfect as it was designed.
GPS is probably more accurate than any car speedometer.


If you ever get to look, check out some speedometer design regulations. They can range from "exactly accurate to (I think) 10% fast", but they can never be allowed to display less than true speed---when they leave the factory.
This accuracy actually changes as the tire tread wears over the life of the tires, so they have to allow for some variations since the speedo and odometer can only work off of the tires rolling on the ground and gear ratios, they cannot actually measure 5280 feet on the pavement for every mile indicated..

Once they leave the factory and you change tire diameter, then accuracy is gone.

 
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But accuracy of my speedometer is otherwise.. i mean if im going 115km/h it doesnt say im going 120 but instead it tells me less which 110.. it makes me more prone to getting a speeding ticket..

 
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Your tires may have a larger diameter than stock tires. I believe the stock tire size for a 2004 LX is 195/60-15. What size tires are you running?

 
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Do you have mods on your car? Like intake?
Cause it can be your intake and rims/tires.

Im in california. I go 70mph on car, but my GPS shows 65mph.
This is caused by intake and rims/tires
I did a test. Stock intake and stock 14' steelies.
I go about 45mph and my GPS shows 45mph.
Then I test with a intake. I go 45mph, my GPS shows 43mph.
Then added 16' rims with 205/40/16 tires
I went on 65mph, GPS shows 60mph.