Quote:
Originally Posted by Dake
Based on GPS data, my digital speedo is consistently 1 mph fast and my analogue is about 2 fast (GPS says I'm going slower than car indicates), so "eh". Even when I'm flying I'm held to +/- 5 kts. Anything closer than that is showing off   . |
That's about normal.
US regulations require the speedo to be accurate to within +- 5 MPH at 50MPH. However, UK and some other countries say the speedometer cannot show you going slower than your actual speed.
Because of this most cars have a bias where your speed is under-reported.