Speedo Calibration

[Lance Cann]

Interesting find, Anyone else notice this.... My truck (2004) has the premium pkg. and came with 255/70R16's on it from the factory. Even says so on the door sticker. Today while driving with my GPS I noticed that the GPS was showing only 58mph when my speedo was showing 60. I got to thinking, I wonder if Ford actually calibrated these trucks for the bigger tires. So I compared the 235/70R16's to the 255/70R16's on a tire calibration website just a few minutes ago and what do ya know... shows that the bigger tire would be reading 57.8mph at 60mph. Now, I am planning on putting 245/75R16's on this truck shortly which will throw the speedo out even more, there would be almost a 5mph difference according to the website. I am thinking of having the speedo calibrated once I get the new tires put on.

 

[TRACket Paul]

I am thinking of having the speedo calibrated once I get the new tires put on.

That would be good thinking. I seem to have the same issue.

 

[Todd Z]

I had to recalibrate my speedo when i got my truck,,,,,, I also had to do it with the gears..



Todd Z

 

[Lance Cann]

anyone know if there is a programmer to do this, or does it have to be done through the dealer?



I have a laptop with an OBDII cable, but I don't know what software or if that will work.

 

[Kevin Palmer]

Mine was off as well. No matter the speed it displayed, I was going a few MPH slower.



Figured it saved me from a ticket if nothing else, well,, that and my badge.. LOL

 

[Todd Z]

Only the XCAL can do it or the calibration boxes....



Most dealers will not do it for you.... they don't want the liability..



Todd Z

 

[Bill Barber]

Tires, gears, whatever, a few miles lower, a few miles faster, no biggie

using a GPS I find with my tire size change I am at 60 MPH actualy going 60.3 miles per hr

DOH

 

[Lance Cann]

Yeah, It's not a big deal, if it is going to cost me a whole bunch of money to buy some fancy calibrator I will just learn to drive slightly faster than the speedo shows.

 

[Robert Caffyn]

We have quite a few of those roadside radar units that display your speed. When I'm not trying to see how high I can get the display up to, a quick check of the speedo and its usually right on. NO, these don't take your picture, but it sure blinks like crazy when you hit 10mph over the speed limit. Yes, I've pinned it at 99 then the screen goes blank. Hee Hee, just havin a lil fun! :wacko: