This will sound impossible, but it happens. Wish I had a picture. I have a 7000 lb GVW trailer with removable ramps. They have a piece of angle iron (with the leg pointing down), that nests in a piece of angle iron (with the leg pointing up) that is welded to the trailer frame. I back my B2650 onto the ramps to load onto trailer. There have been several times when as the wheel first contacts the ramp, the end of the ramp that is setting on the trailer will lift several inches off of the trailer bed. Of course as I continue to back up, the ramp drops back down onto the trailer. Might be OK, because the tractor has only started up on the ramps, but it makes me nervous. Thought about welding a tab on the up hill end of the ramp that would stop this, but didn't really want to modify a safety related feature on the trailer.