[Justin Stiltner]

Take a look at R33 of the manual, that is the rule that most directly applies to what you want to do. I have never seen a requirement of how much of the height of the bumper must be supported, likely the "must be securely mounted" would come into play here.

If you want to be sure about not encountering a problem, I encourage you to build a square(or whatever shape your chassis is) of material behind the bumpers with at least some elements supporting half of the height of the bumper. This does not guarantee you will not have issues in inspection, but will likely pass, and will not hurt you if you are not close on weight.

As a piece of advice from someone that has been doing this for a while, unless you have an EXTREMELY good reason for having your frame that low, raise the lowest point of your robot up some, at least to 1". This is not battle bots, you do not need to worry about other robots getting under you and flipping you. With only .1" clearance you will snag yourself on the carpet any time you are near the field boarders (metal pieces of the boarder extend under the carpet and cause a bump there of 3/16" height depending on the field, and you will likely not be able to go up the ramp.

Good Luck