:When I drive 120kph like I would like. I drive in fact 96 kph and when I drive a real life 140kph on my speedo it's 180kph which is insane. :My speedo his a Mine's on a US car so I don't know if it wasnt set correctly and I dont know how I could fix this issue. :It's very annoying.
A Mines speedo is probably calibrated for a JDM car. USD and JDM had different size rear tyre profiles which will throw it off. And as the other replier states is it a TT or NA speedo and is it fitted in the right type of car