FishingBen

Dude! Seriously?!?! If this is the case I will not be buying a 2012 Ford next month for the basis of my next truck build. I'm distraught to learn this! WTF!!! This ruins all my plans for this project build sheet I've been working on for the last 4 months. If this is the case I'm gonna be P.O.'ed!

shortride

iTrader: (1)

There's always the option of an aftermarket tuners that will adjust to different size tires.

motox151

The Ford IDS will only program certain tire sizes up to about 33 inches. If a dealer says they can program up to 36 inches they are smoking spice. It will not only you to manually program sizes, it has pre programmed sizes that ford allows in the IDS. Example, my buddy put 295/18's on his 2005 fx4 and we had to use a 305/17 to get the diameter close.

You WILL need to get an aftermarket programmer to change that. My SCT SF3 goes by revs per mile. I am running 35x12.5x20 and put in the revs per mile and my speedo is perfect.

motox151

PS I was the tech at our dealership who did all the reprograms/lifts and fun stuff so I know what works. Any questions feel free to ask

KNUCKLE BUSTER

You can program 35 inch tires 315-70-17 these are 34.5 for the raptor thats it other than stock sizes. It dosent matter on your rim size as long as diameter is close to 35 inches.

ftrucktough

Seriously?! What is the big deal?! Who cares if the speedo is off by a couple MPH max... i doubt you set the cruise to the exact speed limit anyway (i hope not anyway!)

motox151

yeah thats the 17 in size, not the 305 as I stated. Because the 295/18's he put on were just over 34 in tires

FishingBen

Its shift points and overall computer controlled vehicle efficiency issues. I guess the Raptor tires are the same diameter. So I'll be fine.

NASSTY

The service manager at my dealership told me he couldn't program the 315-70-17 Raptor tire size to my 2011 FX4, only the 275/65/18s or the 275/55/20's that were options on the 2011 FX4. I dunno if he is correct or not, but that is what he told me. I inquired about it because my tires are pretty much exactly the same diameter as the Raptor tires.

rockstarfx4

Not really sure what the answer is here but I have 325/65/R18s and at the Ford dealership they recalculated my speedo and it reads the same as my Garmin GPS. Just my 2 cents.