Upgrading to a larger tire

[FordPSD6.0]

I have a 2007 SD that has the 20" tires. They're LT 275/65-20. Anyone know if you
can go to a LT 325/60-20 tire on the factory rims. I don't know the rim width. Plus
when I go to the larger tire will the Ford Dealer have to recalibrate the speedometer
or does the computer recalculate it on it's own?
Thanks.

 

[DaveBen]

I can't help you with the rims, I have 16 inch rims. The dealer or good mechanic will have to re-calibrate your computer. They are not that smart.

Dave

 

[Dogman]

A tuner or a Dealer can re-calibrate the shift point in the trans. and the speedo.

 

[NJsix7]

I think u can only calibrate to about 35" with a tuner or at dealership so a 325 might be ok. Not sure if guys are still using the hypertech speedo tool ??? But u could look into that.

 

[Ziefer92]

I think u can only calibrate to about 35" with a tuner or at dealership so a 325 might be ok. Not sure if guys are still using the hypertech speedo tool ??? But u could look into that.

Seen that speedo tool $300sh at AutoAnything, any other tools like that?

 

[NJsix7]

Not sure

Seen that speedo tool $300sh at AutoAnything, any other tools like that?