How big of a gap can there be from the actual chassis frame to the piece of wood used for the bumpers?
you should keep your bumper questions in your main bumper thread, especially since it has the same title.
I have answered here:https://www.chiefdelphi.com/forums/showthread.php?p=1646566#post1646566
Did you read the rules? maybe something about 1/4"? I’d want to check the rules though, instead of relying on my memory.
According to rule R31:
“BUMPERS must be supported by the structure/frame of the ROBOT (see Figure 8-7). To be considered supported, a minimum of ½ in. (~12.7 mm) at each end of each BUMPER wood segment must be backed by the FRAME PERMIETER. “Ends” exclude hard BUMPER parts which extend past the FRAME PERIMETER permitted by R29, part B. Additionally, any gap between the backing material and the frame:
A. must not be greater than ¼ in. (~6 mm) deep, or
B. not more than 8 in. (~20 cm) wide”