My speedometer is off, according to my Garmin GPS and an app that uses GPS to track distance traveled over time. When my car's speedometer says 84, I'm actually only traveling 80. 53mph on the dash is only 50mph according to GPS, so naturally I became curious. My questions are:
1. Does the odometer feed off speedometer's reading? If so, were I to travel 80mph (according to GPS) for one hour, would I actually have put 83 miles on my car's odometer?
2. How does the odometer work? If I put bigger tires on the car, would I actually travel farther than my odometer would have me believe?
The vehicle in question is a 2006 Subaru Impreza 2.5i. Thanks for any and all help. And please pardon my NASIOC naivete if this is in the wrong section.