you dont need 2 gears but you need 4wd make sure it is low as posible i buile one for a shafy project i have going at home that is a 9 tooth off the motor to a 86 tooth, then that again twice then it gos to the axles so it is super low and that is for an electric motor, yours should be low also, so you can run the motor at higher throtal with less speed.