Upgrading tires and wheels - will the computer need tweaked?

[Bellime]

Finally pulled the trigger for BFG K03 285/70 R17 and ICON Recon Pro 17” from my stock OBX wheel. I had purchased the Ford Performance tune a year ago also. With all that said, I believe I need to make some adjustments in the computer for the speedometer.
How?

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[PWillette]

Someone will chime in but I do believe tire size can be adjusted w/ FP tune or can be adjusted in Forescan or aftermarket tuner.

 

[userdude]

Ford ProCal has a setting that allows you to go up to 37" as an adjustment. It's not in inches, though, you have to make a conversion to another unit. There's other threads that describe the calculation.

 

[Brian_B]

https://www.bronco6g.com/forum/thre...eedometer-with-forscan-for-2021-bronco.23064/

Or FPT screen has it built in.

 

[Bellime]

So if I read the massive amount of information correctly. Even though I have the Ford Perf Tune module I would also need the ProCal software on a PC running Microsoft OS. That sucks as I am a MAC user.

 

[PWillette]

So if I read the massive amount of information correctly. Even though I have the Ford Perf Tune module I would also need the ProCal software on a PC running Microsoft OS. That sucks as I am a MAC user.

You could check out the Superchips Flash-Cal...does tire size, disable ASS, disable dbl honk and a few other things. Fairly inexpensive, doesn't require a computer and can revert back to OEM settings.
https://www.holley.com/products/tun...andheld_tuners/superchips_flashcal/parts/1546

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