It just allows you to use different pinion and spurs, for example 416 cant fit bigger than 42 tooth i think, if you lower, you would'nt need to use 42t and use a smaller one
How about "內齒比"? The example u mention is final gear ratio. Different 內齒比 can have same final gear ratio. But i am not very sure what is the different in performance.
if the final gear ratio remain constant.
the higher the internal gear ratio......
you will gain a higher torque compare with the same final gear ratio....theoretically
Brother....as what you say......more torque and quicker pick up response..
^^v