For those of you with some more technical insight, since most of the systems in new trucks are computerized (I have an '09), when you change tire sizes, can I just go to the dealer and have them update something in the computer settings to adjust for the change? That way the spedo and odo adjust to the new size? As a computer nerd, it seems to me that would be a very easy thing to code, and would help Ford roll out trucks with different wheel sizes without hard coding different computers for different tires.

Is this just a dream? I guess I could contact my dealer, but they never seem to be open when I think of these questions at 10:00 at night.

 

yeah the dealer will adjust your computer for larger tire sizes for around $100 or so but you could also get a programmer that will do it too and make the truck much more fun to drive.

 

Funny, I always seem to find an answer right after I post a question. Let' try to change this a little, does anyone have any suggestions for a fairly inexpensive programmer? I'd like to be able to switch between 17" snow tires in the winter, and maybe 18's or even 20" in the summer. One or two swaps would pretty much pay for the programmer.

 

Remember it's the tire diameter you adjust for. Not the wheel. I use an Edge programmer to adjust for tire size.

 

Right, but I am thinking of going from a 245/70-17 in the winter to something like a 275/55-20 or larger. Based on this neat little site:
http://www.miata.net/garage/tirecalc.html
It shows a difference of about 1.5". Even the snow tire is .5" change from stock.

I found a hypertech programmer that just handles basic speedo changes for about $230. That's just over 2 seasonal trips to the dealer for the change. I'm going to post over in the programmer forum to get some opinions, but I'd be interested in opinions here too!

 

I have heard nothing good about hypertech programmers except when that when there taken out there truck it runs better. I would get an edge programmer cause then if you decide someday to spend some more money you can always get it upgraded to a Gryphon and get custom tunes.