Tire change/speedo question

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Aug 19, 2010 | 07:50 PM

Sleepsafe

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Tire change/speedo question

If I change from stock tires to 35's on my 08 F250 does some sort of calibration need to be done to the speedometer for accuracy? And can I do it or does it need to be done at a dealers? Thanks

Aug 19, 2010 | 10:23 PM

snakeside

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The dealer can usually do this, they can reprogram up 2 sizes and down 2 sizes from factory, so if you were born with 18's or bigger you are golden. Another option is ice cold auto air, they all recalibrate speedos. Lastly you could get a tuner/programmer and do it that way and add a ton of power. There's your options.

Aug 20, 2010 | 06:01 AM

redford

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From: Stephensville WI

You need the revolutions per mile of the new tires. This is the number the programmer will need.

Aug 20, 2010 | 09:21 AM

semperstrokin

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I went from 265/70/17 to 285/75/17 (toyo m/t) and the dealer said that they were not able to recalibrate the speedo on my 2005 F250. I printed out the revolutions per mile sheet on Toyo's web site for them. fyi.. As a side question dose it due any damage to the transmission if the size is not programmed in the PCM ?