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2006 Kia Sorento 3.5 5sp Auto
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Discussion Starter #1
So most people know that the instrument gauge clusters speed is out by about 3/4 km/hr.

Well it seems that the cars sensors measure the correct speed your driving, and its just the display that is inaccurate. Also it seems that the cars ECU holds the 'accurate' odometer reading and the one on the instrument cluster shows one that is out by about that same 3 or 4%.

Just out of curiosity i was playing with the ODB2 adapter and i have an app on my phone to read the info. My instrument cluster reads that the car has travelled 135 958km, where as the OBD2 readout shows 130 066km

Works out to about 4.4% on my car.
From my knowledge most other cars house the odometer reading in the ECU, so you can change the cluster and the odometer doesn't change. That is of course the cars that have a digital readout.

I just thought its worth a mention as i thought the odometer would be accurate!
Now that i have changed the tyre size to 245/75/16 from 245/70/16 the speedo is now (almost) accurate, so will be interesting if as a difference between the two odometer readings, from this point forward the percentage difference changes to a smaller difference...
 

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So most people know that the instrument gauge clusters speed is out by about 3/4 km/hr.

Well it seems that the cars sensors measure the correct speed your driving, and its just the display that is inaccurate. Also it seems that the cars ECU holds the 'accurate' odometer reading and the one on the instrument cluster shows one that is out by about that same 3 or 4%.

Just out of curiosity i was playing with the ODB2 adapter and i have an app on my phone to read the info. My instrument cluster reads that the car has travelled 135 958km, where as the OBD2 readout shows 130 066km

Works out to about 4.4% on my car.
From my knowledge most other cars house the odometer reading in the ECU, so you can change the cluster and the odometer doesn't change. That is of course the cars that have a digital readout.

I just thought its worth a mention as i thought the odometer would be accurate!
Now that i have changed the tyre size to 245/75/16 from 245/70/16 the speedo is now (almost) accurate, so will be interesting if as a difference between the two odometer readings, from this point forward the percentage difference changes to a smaller difference...
Well, I don't know about yours, but my 04 Sorento came stock with 245/70/16's, so I would already be close to accurate. Also, most cars can be reprogrammed when larger tires are added, it also corrects the speedometer, too. It would depend on the scanner, but the one I am thinking of is called a Tech 2 scanner. It gets deeper into the system then a standard scanner, and WAY farther than the universal OBD adapters for cell phones. Just some food for thought :)
 

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10 Optima LX, 07 Rondo EX, 89 Chevy C1500
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Well, I don't know about yours, but my 04 Sorento came stock with 245/70/16's, so I would already be close to accurate. Also, most cars can be reprogrammed when larger tires are added, it also corrects the speedometer, too. It would depend on the scanner, but the one I am thinking of is called a Tech 2 scanner. It gets deeper into the system then a standard scanner, and WAY farther than the universal OBD adapters for cell phones. Just some food for thought :)
The Tech 2 is the GM factory handheld scan tool. It will not work on Kias. However, some GMs, through the Tech 2, could have the default tire size changed in the ECM. No Kias that I know of can have this done.
 

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2006 Kia Sorento 3.5 5sp Auto
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Discussion Starter #4 (Edited)
The universal ODB adapter simply allow you to read codes.
The software is what determines if you can or can't read the codes.
And i would say the software that i have would read all codes from what i have seen.
And i dont really want to do more than read codes/figures and reset CEL lights, so its perfect.

And i stated that i previously had 245/70/16, which were factory. 4% is pretty close, but its not correct, which is what i am getting at, and over the years the difference only gets larger and larger between the displayed odo and the actual odo
 

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The Tech 2 is the GM factory handheld scan tool. It will not work on Kias. However, some GMs, through the Tech 2, could have the default tire size changed in the ECM. No Kias that I know of can have this done.
I have never heard of the Tech 2 being a GM only tool, especially since I have seen it used on a Ford Ranger to change tire size. The guy that I know that uses it also uses it to program BCMs because he owns a body shop as well, uses it for all kinds of vehicles. Some are harder to get it to connect to properly, but I have seen it done. I wonder if the difference in mileage is from Kia programming it to work with one tire size and then decided on a slightly different size on shipment, and figured "hey, 4% isn't that bad, no one will notice. lol
 

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2009 Sportage, 98 Sportage, 2012 Tata Xenon, 1944 Jeep
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And i stated that i previously had 245/70/16, which were factory. 4% is pretty close, but its not correct, which is what i am getting at, and over the years the difference only gets larger and larger between the displayed odo and the actual odo
Yes same as mine, how do the 75's fit? I'll probably do the same thing come time to replace my tyres.
Believe it or not the 4% under read is not only allowed for, but actually permitted by the AUS design rules. Manufacturers are not allowed to EXCEED the measured speed, but are allowed to understate. (up to 10%) It is supposed to be a road safety thing! If you look around any car forum for any recent build vehicle you will see many similar complaints regardless of the make.
 

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2006 Kia Sorento 3.5 5sp Auto
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Discussion Starter #7
Cmar, i know its weird ADR thing, but i would have thought that the odometer reading displayed would be the correct reading.

How do the 75 profile fit?

I lifted the car first and then put them on, so i can not say how they look stock.
Lift is Dobinson springs OME shocks.
when i lifted it the 70 profile tyres were still on and it didn't look right.
With the lift the tyres just looked too small due to the clearance between the tyre and the guard. But when fitting the 75 profiles it looks just right again. (obviously just higher).

I can take a photo if you want.
But with the 75's on stock height, i dont really think there would be any issues.
But it will fill up the guard a lot more.

In the 70 profile i had a worn out set of Silverstones. Purchased the car with them on. They were the BFGoodrich knock offs. Look exactly the same.
I have to say they were an excellent tyre. Low(almost none) road noise from a worn out tyre, still had plenty of grip.
I put on Cooper AT3's and they are not as grippy in the wet or in the dry.
And a little bit more road noise.
Still very new (less than 1000km) on the tyres, but if they keep going the same, reasonably happy with my purchase for now, but wont be getting the Coopers again. Probably try the Maxxis. They seem to have a knock of of the Bridgstone D694/D697 range. And they get good reviews too.
 

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2009 Sportage, 98 Sportage, 2012 Tata Xenon, 1944 Jeep
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Hey thanks for that. Mine has Bridgestone Duler A/T's on it at present. They were fitted by the previous owner at 70,000 Km presumeably when the Hankooks wore out. They grip well wet or dry but are pretty noisy, not sure that I would buy them again given that they are $250 apiece. THe silverstones sound interesting.
 
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