[EricH]

Originally Posted by the man

Wait why only have 4 touching at once? This seems to be counterproductive. Why not just use a 4 wheel drive at that point?

Because if you're using a 4WD, your robot bounces all over the place when trying to turn.

The 6WD gives six wheels either contacting or skimming the ground with a shorter wheelbase, which allows for much better turning.