[BJC]

Our team has done a lot of personal testing and evaluation on the top teams in the league and we have found that the CoG and tortional stiffness is generally what sets their robot's drivetrain apart from most others.

CoG, contrary to popular belief we have found that setting the CoG far to one side on a 6wd is best. A 6wd performs best when it is actually a 4wd with 2 extra wheels. Placing the CoG in the middle generally results in the turning point of the robot changing in the middle of the turn as the robot accelerates/decelerates and the outer wheels alernating touching the ground. This is especially important because a 6wd does not turn about the middle wheels but rather between the middle wheels and whichever pair of outer wheels happens to be touching the ground. So by limiting rocking as much as possible performace greatly increases.

Tortional stiffness is absolutely critical to a good 6wd. In 2008 we discovered that without a very stiff chassis the opposite outer wheels will touch down essentially creating a long wheelbase while turning. This will also seriously limits turning.

Edit: I forgot to add, an 8wd has mathmatically much better turning characteristics than a 6wd provided the wheels are properly spaced.

But don't take my word for it, if you don't believe me run some experiments.
Regards, Bryan