User Manual
Evolution    FORD 4.6 and 5.4 Liter 
19 
Tire Size 
The Evolution has the ability to correct for changes in tire size. If you have 
changed your tires to a different size the PCM will miscalculate vehicle 
speed which can affect shifting as well as the speedometer. Correcting the 
tire size will allow the PCM to accurately calculate vehicle speed and 
odometer readings. You will not need to change the value displayed if you 
are running factory size tires. After choosing to set your tire size, the follow 
screen appears: 
The numbers on this screen represent the circumference (in mm) of your tire 
size. The default value the Evolution displays is the current value stored in 
the PCM. Adjust the tire size by pressing the [UP] and [DOWN] arrow keys. 










