question for someone smarter than me

There have been plenty of people that have added 1 size bigger tire or even to 33's where they have done no calibration to the system and have reported that the speedo is dead on and milage is correct on paper vs the computer.

 

Not to start an argument with a person i don't know. Or bomb someone else's thread. That still doesn't mean the computer adjusted. It can't without changing an input. It just means it was wrong the other way before they changed it. My old sport trac was 2 mph slow on the Speedo from the factory. They don't program them to the sensors installed. They put on a base calibration with an acceptable range of error.

 

@JaCado @LSUfan1975 wrote what I was going to reply.