Tire circumference variants coding

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dillenger1

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Doing some spelunking into the instruments coding . Found a byte with multiple tire circumference variants.i have a set of 18" detroits id like to put on my car but are slightly different rolling radius. like a 7 revolution difference per mile.
either way is there a way to determine value of each variant ?im new so go easy
 
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Uwe

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Doing some spelunking into the instruments coding . Found a byte with multiple tire circumference variants.i have a set of 18" detroits id like to put on my car but are slightly different rolling radius. like a 7 revolution difference per mile.
either way is there a way to determine value of each variant ?im new so go easy
Byte 3, bits 0~2 in your Instrument Cluster's coding?

I have no documentation what the eight different "versions" would equate to. But 7 revolutions per mile might be a 1% difference, tops. I think you'll find that none of the tire circumference variants are intended to accommodate such minute changes.

-Uwe-
 
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dillenger1

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Byte 3, bits 0~2 in your Instrument Cluster's coding?

I have no documentation what the eight different "versions" would equate to. But 7 revolutions per mile might be a 1% difference, tops. I think you'll find that none of the tire circumference variants are intended to accommodate such minute changes.

-Uwe-

so those wouldnt be to adapt different sizes of tires on different models?
 
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Uwe

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so those wouldnt be to adapt different sizes of tires on different models?
Yeah, they may very well be. But they would generally be set up to accommodate more substantial changes than you're making here. For example, Tiguan or Atlas-sized tires.

-Uwe-
 
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dillenger1

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the detroits are from a mk6 GTI .you would think one of those variants is for exactly that tire size.flash file configuration may change variants to different size chassis.IDK
 
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Given that the speedometer is setup to over read by around 5-7% and the number or revolutions per mile is well over 1000 the effect of a difference of 7 revolutions per mile on accuracy of speed and distance is insignificant. Especially if you take into account the variation between a brand new set of tyre and an old set of tyres...
 
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dillenger1

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Given that the speedometer is setup to over read by around 5-7% and the number or revolutions per mile is well over 1000 the effect of a difference of 7 revolutions per mile on accuracy of speed and distance is insignificant. Especially if you take into account the variation between a brand new set of tyre and an old set of tyres...

16" stock tire is 811 revs per mile.GTI detroit 18" does 804.isnt there a calibration procedure for the odometer?
 
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Uwe

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16" stock tire is 811 revs per mile.GTI detroit 18" does 804.isnt there a calibration procedure for the odometer?
No, there isn't.

-Uwe-
 
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dillenger1

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ok..so my mk7 ,under tire menu , my display only shows" winter tires" with the speed alarm .
shouldnt I have another option for "summer"?and is this a different set of variants when cycled between the two?
 
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PetrolDave

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ok..so my mk7 ,under tire menu , my display only shows" winter tires" with the speed alarm .
shouldnt I have another option for "summer"?and is this a different set of variants when cycled between the two?
Nope, the Winter Tires option is only there so you can set a speed warning when winter tires (which normally have a lower speed rating) are fitted - it makes no changes to the odometer or speedometer calibration.
 
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dillenger1

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Nope, the Winter Tires option is only there so you can set a speed warning when winter tires (which normally have a lower speed rating) are fitted - it makes no changes to the odometer or speedometer calibration.

my mind is blown!!!!thanks guys
 
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tmoe

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No, there isn't.

-Uwe-

In the old mk5 mk6 golf world you could change impulse distance, does that not exist for newer vw models?
 
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Uwe

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In the old mk5 mk6 golf world you could change impulse distance, does that not exist for newer vw models?
I cannot make a blanket statement about "newer vw models".

-Uwe-
 
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