I drive a SsangYong Musso, and the speedometer consistently reads a few miles per hour above my satnav. I have always believed that the satnav would be the most accurate and reliable, but I recently ...

Thanks to GPS satellites, ClassicInstruments' Sky Drive can turn your speedometer into the world's most accurate speedometer possible by updating 10 times per second! Plus, it can be a GPS enabled ...

Are automobile speedometers set accurately or just “generally”? I always assumed that a car’s speedometer accurately reflected the driving speed, assuming there is nothing wrong with the speedometer.

Q:I operate two vehicles with two different aftermarket GPS systems, each gives me conflicting speed readings in relation to the vehicles' speedometers. Which is more reliable, the factory installed ...

GPS’s calculate speed using distance travelled over time. Your phones consumer based built-in GPS typically has a stated accuracy of 1-3 metres, I would not trust your phone for a reading finer than ...