You know...I have the calculation on the tip of my tounge. Using the speedo and the tach, what is the most accurate way to calculate your gear ratio? Your help is appreciated.

 

Well there are many points that can cause error trying to do it this way (tire size, speedo error, tach error), It would be more accurate to jack it up, mark the drive shaft, turn the tires one revolution and see how many times the drive shaft turns.