It's a well known fact that speedometers in cars are not precise. Most measure the rotation of the main shaft, behind the gearbox, not the vehicle speed. So if you fit different diameter wheels your speed is going to be already off the mark. You can have your speedometer calibrated, but that is pretty costly. I find myself relying on the speed measurement of my satnav more than the one in my dashboard, specially if they are long trips. It's also pretty good at telling me what the maximum speed is of a particular road even if I missed the roadsign, which has saved me a few times as well.
Best regards,
Leo van Miert
Horsepower is how hard you hit the wall --Torque is how far you take the wall with you
Leo van Miert
Horsepower is how hard you hit the wall --Torque is how far you take the wall with you
