Recently installed the Edge on my 2006 F150 FX4 w/ 35" tires. I'm running the Level 2 program and only modified the tire size to 2792 to reflect my 35" tires. I was hoping this would calibrate the truck's speedometer to give me accurate readings but noticed that the truck's speedometer is still 2-3 mph faster than the reading I get on the Edge. Is this normal, and if so, which reading is correct? Is there something else I need to do to the truck's speedometer if the Edge's is the right reading?

 

This is normal, and it is discussed in the user's manual. Check out page 5 of the Edge user's manual here. Specifically, look at the information on the MPH PID.

For the most accurate MPH reading, perform the rolling tire measurement procedure discussed on page 16.

 

thanks for the heads-up.