Speedometer readings w/tire change?

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Nov 27, 2007 | 02:37 PM

MACKASH

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Racer

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From: Oxford,MS Destin,FL Top Down..........

Speedometer readings w/tire change?

How much will the speedometer be "off" when going from a 275/40/18 (stock size) to 285/35/19 tire?

Thanks~

Nov 27, 2007 | 02:38 PM

phoenixfoundmac

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From: KY

Virtually none.

Nov 27, 2007 | 02:43 PM

OhioDave

Burning Brakes

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From: Granville Ohio

St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16'17-'18-'19-'20-21

This is a great tool to get your answer.

http://pw1.netcom.com/~sgalaba/tiresize.htm#TireSize

At 65mph on the original tires / Speedo would read 64.53 with new size.

As stated above, virtually no difference.

Last edited by OhioDave; Nov 27, 2007 at 02:50 PM.

Nov 27, 2007 | 02:56 PM

MACKASH

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Racer

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From: Oxford,MS Destin,FL Top Down..........

Quote:

Originally Posted by phoenixfoundmac

Virtually none.

Exactly what Ohiodave's chart confirms.

Any ideas why the speedometer is reading 17 mph slower than actual speed?

Nov 27, 2007 | 03:23 PM

OhioDave

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From: Granville Ohio

St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16'17-'18-'19-'20-21

Quote:

Originally Posted by MACKASH

Exactly what Ohiodave's chart confirms.

Any ideas why the speedometer is reading 17 mph slower than actual speed?

That sounds like a computer program glitch??? Are there any codes on the DIC?? You haven't programed with a Hypertech Tuner or anything have you?

Good Luck

Last edited by OhioDave; Nov 27, 2007 at 03:55 PM.

Nov 27, 2007 | 03:36 PM

MACKASH

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Racer

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From: Oxford,MS Destin,FL Top Down..........

No hypertech tune only the one Cajundude did when at his shop. I checked and there are no codes. Will the computer show codes if the problem is in the tune?

Nov 27, 2007 | 04:01 PM

OhioDave

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From: Granville Ohio

St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16'17-'18-'19-'20-21

Quote:

Originally Posted by MACKASH

No hypertech tune only the one Cajundude did when at his shop. I checked and there are no codes. Will the computer show codes if the problem is in the tune?

Thought maybe if the computer was reprogrammed for your tire size change that maybe a wrong setting was punched in. Was just a thought