[EricH]

The bumper must be between 2" and 10" from the floor (within the bumper zone). If you have your frame higher or lower than the 2"-10" window, then you do need to have something within that zone where the bumpers are mounted. (See the bumper rules.)

The frame itself can be anywhere from 0-60" from the floor (any higher and you're outside the sizing box). But for the sake of not tipping over, I'd suggest placing it lower than 60".