The problem with rear-heavy trailers that I care about is instability rather than bounce. I can recall my brother taking a load of bluestone blocks home one Saturday morning with a fairly huge single axle trailer (on truck wheels). He had laid the stones evenly over the whole floor space, and had perhaps 100 lb or so on the tow-ball, so he thought he'd just about get by, but the trailer still hunted laterally somewhat (the rule-of-thumb minimum towball load for stability is 10% of gross trailer mass, and he had about 3 tonnes back there). That could be managed, with close attention, but he got into a difficult situation. A couple of guys in front of him (on a divided road, 70 km/h limit, 3 lanes each way, heavy traffic) were holding a full sheet of plywood on the roof of their car by each having a hand out the window. As you might expect, the wind caught it and they lost it. People in all three lanes on that side of the road swerved to avoid the sheet, and my brother had to swerve to avoid the swerving cars. The trailer wagged violently and threw 20 or 30 of the 30 lb bluestone blocks off the trailer, bouncing at 60 km/h through the already out of control traffic. Pretty exciting for a few seconds. I only like trailers that are unconditionally stable.
