Originally Posted by mx_599
is this a hard fast rule?
It's a good rule of thumb.... You want to set the damping to be fast enough to return to full extension with out kicking up, but with out being too slow (excessive damping) to let the fork pack up. When the fork packs up, it typically does not return to full extension fast enough before the next bump comes along and compresses the fork even more.... A few series of these and the fork can bottom out.
The way I have set it up is I press down on the bars quickly with open hands, I feel for how quickly the bars return, or if they start to feel like they are slapping my palms, then I'll dial in just a bit more damping (slowing rebound) until it feels right. It's one of those things I think you have to get a feel for. Try some adjustments on the trail and just be sure the fork isn't packing up. I have ridden with a zip tie on my stanchion at times just to see what the suspension is doing.