I am working on a new project. I have been using in hub motors. I want to use a chain driven motor instead. Here is the problem. The speed of the external motors are 4800 rpm The available motor drive gears are from 9 to 13 teeth The available shaft drive gears are from 32 to 89 teeth The size of the Wheel (OD) is about 20 inch. I am trying to keep the road speed down to no more than 37 mph. Is this possible in this range? Or am I going to blow well past that no matter what ratio I choose. My math isn't that good anymore.