Speedo Calibrators and Tranny Controllers Let You Re-Engineer Your Ride
Many auto enthusiasts are driving around with speedometers registering too low a speed because they've mounted bigger tires on their vehicle. This effect occurs because larger tires have a greater overall circumference (distance around the outer edge) than smaller ones do. A tire with a larger circumference will cover more ground per revolution, and it will also make fewer revolutions in a mile than a tire of smaller diameter.
July 15, 2016