Coding for tire/wheel change

Goathog02 · 11-04-2011, 06:26 PM

SIZE change. Is it possible? Google/forum search came back empty.

edirtaynine · 11-04-2011, 06:28 PM

same code as coding for car washes.

Goathog02 · 11-04-2011, 08:03 PM

Thx for the useless reply Jackwagon.

edirtaynine · 11-05-2011, 02:23 AM

anytime

samchoi604 · 11-05-2011, 03:23 AM

I don't understand. Coding for tire/wheel change??

Goathog02 · 11-05-2011, 08:07 AM

Sorry...tire/wheel SIZE change.

Guess the "car wash" comment was deserved now.

Express · 11-05-2011, 08:11 AM

you dont need to re code anything for changes in size....

Goathog02 · 11-05-2011, 09:24 AM

Guess I am not being clear. If I alter the overall circumference of the tires, how do I correct the speedometer reading?

Express · 11-05-2011, 09:31 AM

i guess the jeep guy in me would say to change the speedometer gear, but no coding can fix that for you...

CirrusSR22 · 11-05-2011, 09:52 AM

Quote:

Originally Posted by Goathog02

Guess I am not being clear. If I alter the overall circumference of the tires, how do I correct the speedometer reading?

The stock tire sizes are all within about 1% difference in outside diameter. Not enough that it will ever matter on the speedo.

Tom K. · 11-05-2011, 10:03 AM

Quote:

Originally Posted by Goathog02

Guess I am not being clear. If I alter the overall circumference of the tires, how do I correct the speedometer reading?

1. Calculate you current speedo error as a percentage of true MPH.
2. Calculate the percentage difference in tire revs per mile between your old & new tires.
3. Add step 1 to step 2.
4. This will be your new speedometer error.

For example, if your speedo currently reads 3% high - a not uncommon BMW error - and your new (larger) tires will have 1.8% fewer revs per mile, then your speedo would then be 1.2% high (3.0+(-1.8)).

I'd also advise confirming this with a GPS.

So the only "coding" is done by the driver.

Tom

remmib · 11-05-2011, 10:37 AM

Quote:

Originally Posted by Goathog02

Guess I am not being clear. If I alter the overall circumference of the tires, how do I correct the speedometer reading?

What size are you planning on?

dbjb · 11-05-2011, 10:57 AM

Are we about to see a lifted 3 series with 22" wheels?

Express · 11-05-2011, 10:59 AM

Quote:

Originally Posted by dsbj

Are we about to see a lifted 3 series with 22" wheels?

24

NiVeDh · 11-05-2011, 03:11 PM

There's a way to do this via coding but there are side effects related to cruise control.

tscdennab · 11-05-2011, 03:53 PM

Quote:

Originally Posted by edirtaynine

same code as coding for car washes.

anerbe · 11-05-2011, 06:20 PM

The BMW speedo normally inflates the speedo value vs true speed.

So unless you plan on putting 13" wires, any reasonable upsize should be fine. Just confirm with a gps unit.

Goathog02 · 11-05-2011, 08:00 PM

No...no 24" spinners in my future. Jut wondering, since we can code for tons of other things. Just checking my options.

Bajan Loch · 11-06-2011, 09:10 AM

use this tool to calculate the change in speedometer reading with different size tires:

http://www.miata.net/garage/tirecalc.html

11-04-2011, 06:26 PM	#1
Goathog02 Private 5 Rep 75 Posts Drives: 06 330i E90 /Premium/Sport Join Date: Oct 2011 Location: Lehigh Valley, PA iTrader: (0)	Coding for tire/wheel change SIZE change. Is it possible? Google/forum search came back empty. Last edited by Goathog02; 11-05-2011 at 08:08 AM..
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11-04-2011, 06:28 PM	#2
edirtaynine Major General 81 Rep 6,092 Posts Drives: e92 Join Date: Mar 2011 Location: SoCal iTrader: (0)	same code as coding for car washes.
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11-04-2011, 08:03 PM	#3
Goathog02 Private 5 Rep 75 Posts Drives: 06 330i E90 /Premium/Sport Join Date: Oct 2011 Location: Lehigh Valley, PA iTrader: (0)	Thx for the useless reply Jackwagon.
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11-05-2011, 02:23 AM	#4
edirtaynine Major General 81 Rep 6,092 Posts Drives: e92 Join Date: Mar 2011 Location: SoCal iTrader: (0)	anytime
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11-05-2011, 03:23 AM	#5
samchoi604 Colonel 60 Rep 2,334 Posts Drives: black on black Join Date: Mar 2009 Location: Burnaby, BC iTrader: (3)	I don't understand. Coding for tire/wheel change??
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11-05-2011, 08:07 AM	#6
Goathog02 Private 5 Rep 75 Posts Drives: 06 330i E90 /Premium/Sport Join Date: Oct 2011 Location: Lehigh Valley, PA iTrader: (0)	Sorry...tire/wheel SIZE change. Guess the "car wash" comment was deserved now.
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11-05-2011, 08:11 AM	#7
Express Major General 369 Rep 8,693 Posts Drives: 06 330i Join Date: Dec 2008 Location: The Promise Land iTrader: (17) Garage List 2006 BMW 330i [8.30]	you dont need to re code anything for changes in size....
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11-05-2011, 09:24 AM	#8
Goathog02 Private 5 Rep 75 Posts Drives: 06 330i E90 /Premium/Sport Join Date: Oct 2011 Location: Lehigh Valley, PA iTrader: (0)	Guess I am not being clear. If I alter the overall circumference of the tires, how do I correct the speedometer reading?
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11-05-2011, 09:31 AM	#9
Express Major General 369 Rep 8,693 Posts Drives: 06 330i Join Date: Dec 2008 Location: The Promise Land iTrader: (17) Garage List 2006 BMW 330i [8.30]	i guess the jeep guy in me would say to change the speedometer gear, but no coding can fix that for you...
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11-05-2011, 10:57 AM	#13
dbjb I sweat pheromones 203 Rep 2,103 Posts Drives: e92 335i, retired SLK55 Join Date: Jul 2009 Location: NorCal iTrader: (25)	Are we about to see a lifted 3 series with 22" wheels?
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11-05-2011, 03:11 PM	#15
NiVeDh Major General 422 Rep 8,003 Posts Drives: '08 E90 335i, '99 E36 M3 Join Date: Apr 2009 Location: Houston, TX & Atlanta, GA iTrader: (132) Garage List 2008 BMW 335i Sedan [8.66]	There's a way to do this via coding but there are side effects related to cruise control.
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11-05-2011, 06:20 PM	#17
anerbe Lieutenant Colonel 121 Rep 1,568 Posts Drives: Red E90M 6MT Join Date: Dec 2006 Location: BH, MI iTrader: (2)	The BMW speedo normally inflates the speedo value vs true speed. So unless you plan on putting 13" wires, any reasonable upsize should be fine. Just confirm with a gps unit.
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11-05-2011, 08:00 PM	#18
Goathog02 Private 5 Rep 75 Posts Drives: 06 330i E90 /Premium/Sport Join Date: Oct 2011 Location: Lehigh Valley, PA iTrader: (0)	No...no 24" spinners in my future. Jut wondering, since we can code for tons of other things. Just checking my options.
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11-06-2011, 09:10 AM	#19
Bajan Loch Private First Class 1 Rep 189 Posts Drives: E90 A22 N52N Join Date: Mar 2011 Location: GTA, Ontario iTrader: (2)	use this tool to calculate the change in speedometer reading with different size tires: http://www.miata.net/garage/tirecalc.html
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