I have a 2009 F150 screw 4X4, I am changing the tires from 255 70 17 to 285 70 17. What is involved in recalibrating the speedo? Do I have to take it to the dealer? Should I take it to a local repair shop? Will this effect the waranty? Any input would be helpful. Thanks.

 

It will not affect your warranty. You will need some kind of programmer. Whether that is at the dealer, or you buy one. Would be surprised if a tire company would be able to do it as the programming needed is by vehicle brand and model. Dealer may not even be able to program that size as they are limited in there programmer to OE sizes and a few others. They may have something close though. Example, a 275/65R18 and a 275/70R17 are the same final diameter.

 

I had mine done at the dealer and they said they could only go up or down 1 size......and they charged me way too much...$100

 

It will depend upon the dealer. My dealer did this for me for free. On that I saw the list of tire sizes the could program. As I had gone from a 235/75R17 to 275/70R17, which was not in the list. However as I mentioned above the 275/65R18 was on the list and they programmed for that.