Speedo Calibration Question For Ford Techs
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Junior User
Joined: Oct 2004
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From: SURREY,BC,CANADA
Speedo Calibration Question For Ford Techs
Alright so I've read probably hundreds of posts and threads on tires but none of them answer this specific question to which I think the answer would be helpful to many.
What is the info that the Ford scanner/programmer (dealer model) asks for when calibrating the speedo for various tire and wheel sizes ?
Is it rev's/mile ?
Actual tire size ?
Or wheel outside diameter including tire ?
And just as importantly, what is the maximum allowable measurement for the one that it asks for ?
I know, I know I could just phone a dealer and ask but chances are I'd be talking to a service writer who wouldn't know the answer and suggest that I "just bring it down" once I get the tires on. The problem with that is what if I have installed tires that are too large and can't be programmed, I eat $1000 in tires, no thanks. Some of you may also suggest buying one of the many aftermarket programmers that allows you to enter tire size but I'm not interested in dropping $500 so I can calibrate my speedo when if I go with a tire size the dealer scanner/programmer will accept I can get it done at the dealer for $60.
Thanks for the help.
What is the info that the Ford scanner/programmer (dealer model) asks for when calibrating the speedo for various tire and wheel sizes ?
Is it rev's/mile ?
Actual tire size ?
Or wheel outside diameter including tire ?
And just as importantly, what is the maximum allowable measurement for the one that it asks for ?
I know, I know I could just phone a dealer and ask but chances are I'd be talking to a service writer who wouldn't know the answer and suggest that I "just bring it down" once I get the tires on. The problem with that is what if I have installed tires that are too large and can't be programmed, I eat $1000 in tires, no thanks. Some of you may also suggest buying one of the many aftermarket programmers that allows you to enter tire size but I'm not interested in dropping $500 so I can calibrate my speedo when if I go with a tire size the dealer scanner/programmer will accept I can get it done at the dealer for $60.
Thanks for the help.
Elder User
Joined: Feb 2004
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It goes by rev. per mile. As for how far you can go, I'm not shure some tire sizes are in the programming that can be selected. If there isn't one there to select, we go by rev. per mile. Hope this helps. Also some vary year to year so telling you exactly what sizes are in your calibration, I would have to hook it up unless someone else here knows right off the top of their head.
Postmaster
Joined: Jun 2006
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From: Kzoo
what i dont get is i bought a scangauge 2 for my truck and have it mounted on the dash and the scangauge is the correct speed but the speedo is always off by 2 miles per hour, how could it be off and the scangauge be correct?
Elder User
Joined: Dec 2006
Posts: 662
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From: CO
I've seen several speedometers that are optimistic while the odometer is almost dead nuts. I'd speculate that it's on purpose to eliminate any liability for speeding tickets or something else along those lines.
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Junior User
Joined: Oct 2004
Posts: 52
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From: SURREY,BC,CANADA
Originally Posted by ranger88a
It goes by rev. per mile. As for how far you can go, I'm not shure some tire sizes are in the programming that can be selected. If there isn't one there to select, we go by rev. per mile. Hope this helps. Also some vary year to year so telling you exactly what sizes are in your calibration, I would have to hook it up unless someone else here knows right off the top of their head.
So just to clarify if the tire size is not available you enter rev/mile but is there a limit to the number of rev/mile you can enter ie 600 rev/mile ?
Just in case you are able to find out without "plugging it in" my truck is a 2005 XLT 5.4L F150 which currently rolls on 245/70/17 which according to the door sticker are stock.
