[Benjdragon]

Here is something to think about. The bumpers are about 3.5" thick, so two bumpers adds 7" to the length or width of a robot. Most wheels are going to be mounted at least two to three inches inside the bumpers. So, you can have a wheel right on the edge of a bridge and have the frame and bumper overhang for 5.5 to 6.5 inches on each side. The bridge is 88" long. Subtract 14" for the bumpers of the robots touching each other and you get 74". Add back in the 4" for the distance from the wheel to the frame edge and you get 78". Divide by 3 and you get 26". Three robots with 26" wide frames and that can move sideways (crab drive, mechanum drive) would be able to fit on the bridge. If the center of the whells are more than 2" in from the frame, then you could go with a slightly wider frame.