Just bought an 04 Crew cab 150, and my garmin says i'm going 72 but the speedometer says 80 (example)? ran past a few of those "Your speed is: .... " things and it confirms the garmin GPS each time. Any thoughts on a fix for this or what the issue may be?

Ryan.

 

Does it have oversize tires on it?

 

Almost all if not all of the trucks come off the lot reading about 5ish mph over what they're actually going.

And if you have undersized tires that'll make you read faster than what your actually going to.

 

"Lt275/65r18"

Ryan

 

Either the tires are not stock size, the rear axle ratio has been changed, or it has been misadjusted with a programmer. When the Garmin says 72, the speedo should read around 74 or so.