To calculate the mechanical and speed advantage provided by various gear combinations?

Question

To calculate the mechanical and speed advantage provided by various gear combinations?

Answer 1

You use the ratio of the number of teeth on the interlinked gears. For example, if a 4 tooth gear was driving a 12 tooth gear there would be a 12:4 mechanical advantage or 12/4,  or 3 to 1. And the speed 'advantage' would be the opposite: 1 to 3. When you have multiple interlacing gears, you multiply each ratio together to get the final result. Use your intuitive sense the check that you have the numbers in the right relationship.