Metal sliding against metal equals friction.
The Reese Dual-Cam System relies on friction and tension to do its job.
Where it differentiates itself from other sway controls is that it is a proactive sway control, increasing tension on the WD bar to return the swaying trailer back to center. As the WD bar rides up on the the cam the spring tension built into the bar is increased and tries to force the bar back to center.
It is friction, but it relies on spring tension as well to do its job. The forces at work in the DC are tremendous which is why there are frequent reports of broken cam arms and other misc. broken parts. All of these issues can be dealt with and the DC made to perform excellently. Just something to be aware of.
DC = Proactive sway control
Friction sway (add on sway bars and Equal-i-zer = non proactive sway control (basically dampner)
Thanks!