tire size correction question

[BigSur]

Originally Posted by shotgun

Are you referring to the "engineering test mode"?

Ford analog speedometers are almost always high by 2-3 MPH. At least they have been on all my Fords.

Not really sure what you're asking, but I should have clarified. My speedometer is an actual gauge. However, my odometer and fuel economy readout are digital.....displayed below the speedometer gauge. My odometer and fuel economy readout is inaccurate due to the tire change. I was told this will be fixed once I install the Gryphon and compensate for the new tire size. I'm just curious if this will be set prior to me receiving the unit, both on the canned setting, as well as when I receive my custom tunes. OR, do I have to manually change the tire setting myself and will this in fact correct my truck's display?