You’re on a route that suddenly veers right or left, departing from the straight-line trip you’ve made so far. Not only will you take a serious whip if you fall, but, as internationally certified mountain guide Rob Coppolillo cautions, you’re introducing “secondary pulls” into your system. This added tension on your last piece, compromises safety, and could lead to zippering gear and dangerous falls. Here, Coppolillo, an instructor for Climbing’s Intro to Trad online course, explains secondary pulls and how to avoid disaster when a climb begins to zigzag.
Primary and secondary pulls
During a fall, your last piece—whether it be a bolt, ice screw, or cam—typically experiences a downward pull—this is the primary pull. “Those are relatively easy to anticipate,” says Coppolillo.
But, “Imagine there's a bolt way off to the side, and now you're going to climb to the left, so if you put a short draw on that bolt [in front of you] and then bang a left, the rope is going to make an abrupt change of direction,” says Coppolillo. When you clip that next bolt, your last draw is going to get pulled to the side rather than hang straight down—this potential to get tugged sideways in a fall is called a secondary pull.
The problem with secondary pulls
“Each time the rope goes through that carabiner and bangs a left or right, it introduces friction into the system, and that does a few things,” says Coppolillo.
Say, for example, you have a nut below you that you placed well for a downward, primary pull. But then the route traverses or diagonals, and now you’re up and/or to the side of it—a strong tug to the left or right during a fall could pop it out. Then, compounding the problem, the next piece below it also gets pulled to the side and might pop out too. “All of a sudden, you’re minus two pieces—you could take a very long fall,” says Coppolillo.
The other problem is less apparent. If a rope zigzags up a pitch, the “friction generated by that effectively begins removing rope from the system in terms of how much stretch is available to dissipate energy,” says Coppolillo. Because the rope is moving through all the bends in the system, which introduces tension, less of it is available to catch you and soften the fall, increasing your fall factor and putting more force on your top piece.
What to do
Extend your protection on traversing routes to eliminate or reduce zigzagging. “What you’re trying to do is get the rope to fall as directly and cleanly as possible to your belayer,” says Coppolillo. “If I climb up and right above the belay, put in a piece, and then I know I'm going to climb over to the left, I might extend that piece a little bit and make the bend in the rope more gradual or even nonexistent.”
Coppolillo recommends carrying different-length slings in trad areas, like those at Red Rock near Las Vegas, where the routes can wander. A couple double-length runners, several shoulder-length slings, and a few draws can alleviate issues posed by secondary pulls, he says.
Want to learn more about these and other trad climbing skills? Sign up for the AIM Adventure U Intro to Trad online course.