I have a '05 F350 6.0L with 35" tires that were installed at the dealer when the truck was new. The speedo reads correct, but I have an Edge Evolution and the tire size it displays is 2556mm, but my tires are no where close. If I adjust the Evolution to my actual tire size wont it screw what the Edge is thinking? Should I just leave it alone, am I getting true readings from the Edge or have I ingested to many diesel fumes...and should leave well enought alone??