An objective method is provided for selecting gear ratios for use in a motor
vehicle
transmission having multiple selectable gears. The method includes selecting gear
ratios for a specific application includes calculating a low gear ratio, and a
high gear ratio based upon vehicle parameters and performance requirements. The
total ratio spread is determined by dividing the low gear ratio by the high gear
ratio. Using the total ratio spread, a geometric sequence is created with a plurality
of terms, such that each of the terms respectively represent the ratio steps between
the gears. Lastly, each gear ratio is divided by its respective ratio step plus
one to find the gear ratio for the next gear. This method provides an objective
method for selecting gear ratios, such that the steps between each of the ratios
are uniformly progressive.
