We just did a soa on the 60 and put 35's on. Same springs for now. I figured, by just driving along side my wife's car that the speedometer is off by approx. 5-7miles over so if my speedo says 25 i'm really going like 30-32 mph. Now I don't know how to figure out what that means when my mileage says I've gone 100miles. How much have I really gone?