We spent a lot of time helping other teams move their bumpers up to pass inspections at their first event.
R22: BUMPERS must be located entirely within the BUMPER ZONE, which is the volume contained between two virtual horizontal planes, 4 in. above the floor and 12 in. above the floor, in reference to the ROBOT standing normally on a flat floor. BUMPERS do not have to be parallel to the floor.
We saw many bots with bumpers below the 4" minimum. Inspection is not a great time to learn about that...
Good luck teams!!