[MrForbes]

Interesting point Wayne...I don't quite agree that the bumpers will be overweight if built to the specs, since one of the specs is that they will not weigh more than 15 lbs (please pardon they lawyerspeak). Ours weighed about 12 lbs and went all the way around the robot, which was only 26 x 36", and we used heavy attaching nuts/bolts, and no aluminum angle. I did not find a size specification for the aluminum angle, but I think that if we had used 1/2" x 1/16" angle it might have met weight. I can imagine that it would be very easy to make the bumpers overweight if you were to make them as large as possible and use the angle, or if they were a bit smaller but used more substantial angle.

Overall I think there is a lot of room for creative use of materials and design...the bumpers, motors, electronics, and pneumatics seem to be areas that are limited, but there is good reason for most of the limits.