Speedo is off! Need help.

[one5oh2nv]

Dont know if this is the right section but I have a question. I just bought a 03 f350 and the speedo is off a few mph. I have checked it with 2 different gps units. It has the factory tire size but the speedo reads slow. at highway speeds it is off as much as 6 mph. Around town its off about 2-3 mph.


Is this normal or what can I do?
Also how much is this affecting my mileage on the odometer?

[Jarrod B]

that title........




anyway

what tire size are you running?

[one5oh2nv]

265/75/16

Whats wrong with the title?

[Jarrod B]

Originally Posted by one5oh2nv

265/75/16

Whats wrong with the title?

Lol nothing.


Stock size huh? Then someone musta change the computer tire cal.

[brinker]

Almost all speedos will be off from the factory. Most will read that your going faster then you really are. the speedo if im correct is controled by the ABS i know they make aftermarket modules to correct them for larger tires but i have never messed with them to see how they work.