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Jul 11, 2008 | 10:29 AM

#31

Kevin M

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From: Reno, NV

Car Info: 1993/2000/2001 GF4 mostly red

Quote:

Originally Posted by 4URABUS

You must have short tires on your car, 'cause mine's clockin' ~75MPH @ 3K RPM.

Tires have no effect on the relationship between engine RPM and speedometer reading, unless you've reprogrammed it.

Jul 11, 2008 | 10:34 AM

#32

nachomc

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From: Funtown

Car Info: A limousine with a chauffer

I think I need to punch my friend. The one day he calls me before 10 am, I'm trying to sleep off a serious hang over

Oh well. Free tickets to the A's game for tomorrow night

Jul 11, 2008 | 10:34 AM

#33

Irrational X

plays well with others

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From: Sac

Car Info: your mother crazy

Quote:

Originally Posted by Kevin M

Tires have no effect on the relationship between engine RPM and speedometer reading, unless you've reprogrammed it.

wheel and tire size will, but not as much as you would think

Jul 11, 2008 | 10:38 AM

#34

GT35 STI

Troll

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From: In SoggyNoodles Low Rise Pants

Car Info: 2008 Legacy Spec-B

Quote:

Originally Posted by 4URABUS

I was taught that changing overall tire diameter (and thus, circumference) without reprogramming your speedometer would cause changes in your MPH vs. RPM readings because you have effectively changed final drive ratios.

Jul 11, 2008 | 10:40 AM

#35

iLoqin

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From: No Way

Car Info: Nadda

Or so it should be =0

Jul 11, 2008 | 10:42 AM

#36

Nick Koan

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From: The BLC

Car Info: Legacy GT

Heh, stupid brain. Be more right before coffee next time!

Last edited by Nick Koan; Jul 11, 2008 at 02:30 PM.

Jul 11, 2008 | 11:02 AM

#37

T-Will

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Posts: 10,232

From: Front pleated TWill pants...

Car Info: 2004 PSM WRX

Quote:

Originally Posted by nachomc

I think I need to punch my friend. The one day he calls me before 10 am, I'm trying to sleep off a serious hang over

Oh well. Free tickets to the A's game for tomorrow night

How are things going with your coworker? Did you make her cry again?

Jul 11, 2008 | 11:09 AM

#38

96Imprez

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Posts: 625

From: Wyoming

Car Info: 1996 Impreza Brighton bone stock sadly

hola all, day off due to our city parade, oh yea, 4 day week and i get paid for today

Jul 11, 2008 | 11:14 AM

#39

GT35 STI

Troll

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Joined: Jan 2006

Posts: 15,877

From: In SoggyNoodles Low Rise Pants

Car Info: 2008 Legacy Spec-B

http://money.cnn.com/2008/07/11/tech...ex.htm?cnn=yes

Jul 11, 2008 | 11:21 AM

#40

Egan

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From: Peoples Republik of Kalifornia

Car Info: 05 H2 SUT, 45 GPW, 10 Murano, 13 Boss 302

Off to Plumas Eureka and hopefully out of the smoke!

Jul 11, 2008 | 11:25 AM

#41

Double Phister

Father Time

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From: You're doing it wrong!

Car Info: This aint a bag. It's a shipment.

Quote:

Originally Posted by Nick Koan

Uh what?

Spedo reading are generally affected by the outer diameter of your tires. RPMs aren't, but the delta between the two definitely will if one is.

changing tire size will change the error between actual speed and indicated. But the relationship between indicated speed and RPM will stay the same. The axles are still turning at the same speeds they were before.