Originally Posted by
Broctoon
These examples are not really linear, but they're close. When the number of teeth between steps increases by first 1, then 2, 3, and at the largest cogs by up to 13 teeth, the difference in drive ratio is not as far from linear as it might seem. That's because as a percentage, the increasing number of teeth is nearly the same at each step.
What you’re describing is a geometric progression. There’s nothing linear about it.