How far off the ground do the bumpers have to be, I read through the manuan and they address the dimensions of the bumpers, but not how high off the grounf they have to be
Look for the definition of “bumper zone” in the manual (Section 8) for a full explanation. In short, between 1 in and 2 in.
Actually between 1 and 7 inches.
The BUMPER ZONE is from 1 to 7 inches off the ground. Since a 5-inch BUMPER has to stay within that 6-inch ZONE, the bottom of that BUMPER can be from 1 to 2 inches off the ground.