I searched but could not find an answer to this question. I have a 1951 1/2 ton truck and changed the ring and pinion gear with a 3:55 to 1 change. I have 15 inch tires on the truck with a 4 speed transmission. My question, how do I calculate the actual MPH with these tires and new gears. In other words, if my speedometer says 50, how fast am I actually going. :rolleyes: Any thoughts, or I guess I could follow someone and have them drive 50 to see what MPH my truck is traveling. Any help would be appreciated.
