Why Speed indication diff on Garmin & Speedometer

Thu Jul 21, 2011 1:12 pm

Hi Friends,

I have notices that there is around 10km difference between the Car speedometer and Garmin.

Can anyone please comment on this issue?

regards

Thu Jul 21, 2011 1:24 pm

This is common with most GPS units--not just Garmin. Car speedometers are typically factory set to be a bit 'optimistic' on purpose. This varies between 5-10 KPH usually. With good satellite reception, the GPS tends to be more accurate. But not always.

Thu Jul 21, 2011 1:28 pm

Car speedometers tend to indicate a higher speed than the actual speed. Just consider the Garmin speedometer as more accurate as it measures elapsed time and distance between two points.

Fri Jul 22, 2011 4:40 am

car speedometer indicates higher speed than the actual ground speed. normally, the difference in speed increase as you drive faster. it's sort of a safety measure to make sure you don't get a speed ticket even if you drive at the speed limit of a road. :) and car speedometer reading can change if you have changed your wheels and tires from stock to different sizes. your GPS will indicate true ground speed almost always, as long as you have clear view of the sky. drive safe mate! :)

Fri Jul 22, 2011 7:51 am

thanks all for valuable comments.