Single rope is a leading method, using just one rope (apparently) and clipping it into all his pieces of protection. The main con for this system is that the climber has less rope than other leading methods. This is irrelevant when climbing sort, single pitch, routes (especially sport routes). on [[Multipitch routes, where there's no walk off, less rope means shorter and more rappels. there may be as much as twice rappel pitches as climbing pithces on a route. The pros are that single rope leading is more simple to learn, both for the leader and for the belayer. This is why single rope leading is popular for sport climbing, both on crags and on plastic and is useful whereever there's a walk off or a pre-set rappel route.
Since the leader clips the rope into all his pieces, the rope drag can be a problem on meandering routes, routes with traverses etc. Every time the rope passes through a runner and creates a sharp angle, an extra amount of friction is added. Apossible sollution is to extend the runners (use long runners) and diminish the angle the rope is making when passing through the biner.
Contributions to this page were made by Mica Yaniv and others...