As for gearing up or down, consider a simple example. Consider a lever
3 feet long with the fulcrum at the one foot point. This gives a 2:1
ratio. My 250# on the long end would be able to balance 500# on the
short end. To gear it up, swap ends. Now my 250# would be balanced by
125#. Simple mechanics.
Gearing works the same way. Ignoring friction (you can't but it makes
explanations easier) a gear of 4 inches diameter and a gear ot 2 inches
is the same 2:1 ratio. Spinning the smaller gear at 100 revolutions
spins the larger gear 50 revolutions. Spin the larger 100 and the
smaller goes 200. Simple mechanics.
If you put a 100# resistance on the smaller gear and spin it with the
larger gear, the larger gear will see a 200# resistance, place a 100#
resistance on the larger gear and the smaller gear sees a 50# resistance.
We live is a technologically complex world but many do not understand
simple mechanics.