I would back the GPS over the car's speedo any day. Car manufacturers usually build in a plus reading so that you appear to be going faster than you actually are. Also tyre wear has a bearing, the more worn the tyre the higher the tyre RPM which translates to a faster speedo reading compared to the GPS. The difference of 5Kph is about average.
Well, the GPS unit is right but in a court they wont accept that so if your spedo is slower then the gps stick to the speedo. If your gps is slower then the speedo still stick to the speedo.
But if your lucky like I am my speedo and gps are the same so I dont need to worry...
lol
Speed Difference
