I've got 255x70x17 Continentals on my new '04 STX. I don't like them and wanted to buy GoodYear, maybe Michlin but I wanted to increase the size to 275x65x17.

The problem is that increasing tire diameter will cause the speedo to be off. The next problem is that the Ford service department said that they could not recalibrate the speedometer with the over size tires. They said that Ford Motor Company will not allow them to do that anymore.

What is everyone that changes tire sizes doing ?

 

255x70x17 = 31.06"

275x65x17 = 31.07"

I don't think you'll have to worry about your speedo. My experience is that Ford speedometers are a bit optomistic from the factory. By adding a bit of size, you're actually making it more accurate. I don't think you'll notice a .01" increase.

I'm sure that very soon, Superchips will have a program that offers tire size recalibrations on the new F-150s.

 

I must have misread the size on the '04 Expedition tire. The tires were were the same brand as mine but noticably taller tires. I'm sure they had to be much taller than .01".

 

i put oversize tiers on my f150 and had to change the gear whear the speedo cable hooks to the trans if ford wont do it take it to a 4x4 shop or do it your self

 

I'm going to have my SuperChip reburned to compensate for the difference...

 

most places that lift trucks can do it for cheap