Most speedos, particularly the japanese ones error on the side of bravado.......so when your whinging about being caught at only 6 mile an hour over the limit, that will be the correct speed as apposed to you speedo reading which was probably over 80............
So if you used the speedo reading at for example 70 in a 70 i doubt if you would get a ticket.....Still you think they would put a big needle on it and get it to point at the speed your going...
