I think I may have the answer you are looking for,
Back in 2005 we used a duel CIM per kit gear box setup for out drive, for that game we where happy with how it did. It was simply a pretty run-of-the-mill center wheel drive.
Last year (2006) we used a single big CIM drive that we put into a Kit transmission with a special joining plate on it. We where happy with this one as well.
Here is a link to out 2006 drive train:
http://www.chiefdelphi.com/media/photos/22991
When we where doing driver training our 2006 robot PUSHED out 2005 robot around the room when it needed to and seemed to be in the same ball park for speed. This year we seemed to be able to win or tie most pushing matches we went into against other single speed transmission robots that used the 2 small CIM method. I will say however that most pushing matches we encountered where when we where in scoring positions and out goal was to remain motionless not push the other robot across the field.
If you have any questions please feal free to ask, if i dont know the answer ill find some on who does.
