Quite right, JR. While the springs support the weight, the shocks (dampers) have to be up to the task of absorbing the energy of the road vibrations...and that is proportional to the amount of mass undergoing those vibrations, which is greater for the Rocket than the Bonneville. The principle goes all the way back to Sir Isaac Newton.
I have no idea whether Hagons for the Bonneville can sufficiently dissipate the additional energy without overheating, but I would be doubtful enough not to want to find out the hard way.