[Modding_out]

Originally Posted by BrianG

Yup, that simple.

ratio = output_gear_tooth_count / input_gear_tooth_count.

Thanks! I did it and got good results but what is this*?
4.5:1 <= * the :1?

Edit: I figured out what it means, :1 = 1 full rotation. So 4.5:1 means it the motor 4.5 rotations to turn the tires once.