[Borobo]

I would really recommend against tank treads for 3 reasons:
1) They are more complicated than they appear. you will need the tread (fairly expensive) special wheels, and at least 8 wheels to do them well, and many teams use more
2)There is no large advantage over wheels. It is true that for a defensive robot they are good because they have immense traction, but they are also more inefficient that wheels. It is better overall to invest in a strong offensive robot, because the same charactersitics which make a robot good at offense also allow it to play at least some aspects of defense. For example, our robot this year has high traction mcmaster tread on 8 wheels and switching gearboxes, meaning that if for whatever reason we need to play defense, we will be able to simply push other robots around in low gear; maybe not as effectively as a tank treaded robot, but still enough to be useful in either role