Ideal massless gear. Rigid coupling with gear-ratio
ratio[1]/ratio[end]
Input identical with massive gear 'Gear'.
Gear ratios are defined by relative speed. The following specifications are equivalent
ratio = {6, 2, 1}
ratio = {9000, 3000, 1500}
For memorising
ratio[1]/ratio[end] > 1 if flange_a faster flange_b.