Should I put my motors in the front or the back???
The smart-aleck answer is “Yes”.
The serious answer is “It depends.” To get a useful answer to a question like this, you (the designer) have to describe (to your audience) the machine you are building and the job it will do (and sometimes the environment where it will do that job).
I am not sure what exactly you’re using the motors for. Could you please elaborate?
If it is for a drivetrain, as long as you’re gearing all of your wheels to the appropriate motor on that side then any place is fine, but the middle is a good place for balance and accessability.
That depends on what you want the robot to do. Depending on where you put the motors, the turning of the robot will be different, because you are changing the axis of rotation.
I have seen a lot of robots put motors on the back so that they will have room on the front for intake mechanisms.
Look at the weight distribution of the robot and the center of gravity. In most cases you want the motors to be driving the heavier part of the robot. The weight will push the drive mechanism (wheel, tread ect…) into the ground causing more friction resulting in greater traction.
So I would say that driving the back wheel would be the way to go if you wanted to use 2 motors. Although I personally would link 4 motors on 4 omni directional wheels on either corner but that uses twice as many motors. It can also be done with 2 motors by linking the 2 wheels on each side together with chain or gears.
This is what we do with our robots:
if your doing a standard 4 wheel, 4 motor drive, find your center of gravity. If the center of gravity is closer to the front, put 2 standard wheels in the front, and if in the back, put the standard wheels in the back. Then, put 2 omni wheels of the same size on he opposite side, or the lighter side. This way, when it comes to turning, your robot will hopefully pivot on the standard wheels and swing around on the omnis.
To maximize on turning strength, put 2 motors on each standard wheel, and have the omnies only free wheel. This way, you will have 100% power when it comes to turning.