How to Trim your Climbing Rope
Sport climbers fall a lot, and as a result, they wear out their ropes quicker than other types of climbers (who don’t fall multiple times a day). Typically what happens is that ropes will wear out in one particular spot: about three to five feet away from the end of the rope that you are tied into. Why? Because this is the spot on the rope that gets raked across a carabiner gate as a fallen climber winches him- or herself back up to the quickdraw. The rope rakes across the carabiner gate as you pull yourself back up and doing this over and over ultimately leads to sheath degradation and “dead spots” in the rope’s core.
More than falling, it’s this winching/sawing action that contributes to this type of dangerous rope wear. But the two are also related. Few climbers know that, after a fall, a rope needs a period of “recovery” for its fibers to recoil after being elongated. (Pro tip: After you take a fall, clip into a quickdraw/bolt and hang on that, as opposed to having your belayer hold your weight with the rope. This will help extend the life of your rope.)
If you’re just climbing on new, safe carabiners, your rope will last a long time. However, older carabiners tend to get sharper and more dangerous with age due to the fact that lots of falls and lots of lowers will wear through the aluminum and create sharp edges that eat nylon ropes. Everyone should always climb on their own gear that they know is safe, but it is also a reality that many sport climbers are climbing on “project draws” that have been hanging on routes for who-knows-how-long. Even draws that have been hanging on a popular route for a few weeks have the potential to go from brand new to dangerously sharp. I’m mentioning all this only to explain how and why ropes can get worn dangerously thin.
Now that you know how it happens, the next step is to know how to recognize when it’s time to trim you rope and how to do it.
Trimming your rope means that you literally cut the rope above the damaged spot—which, as I stated, typically occurs about four to eight feet from the rope’s end. The rest of the rope is probably perfectly fine; it’s just that one spot that’s heavily worn. By trimming the rope above the dangerous weak spot, you give your rope a new life and can continue climbing safely on it.
Just know that, obviously, when you cut your rope, it gets shorter. If you have a 60-meter rope and are lowering off of 30-meter pitches, you won’t make it all the way to the ground after cutting the rope. This is one reason I recommend that sport climbers purchase 70- or even 80-meter ropes, even if you’re only climbing shorter routes. Ultimately, a longer rope is more bang for your buck. You can trim your rope end several times before it becomes too short to be useful.
How do you know when it’s time to trim your rope? Inspect your cord every time you climb. As you flake it, feel for soft spots in the core, and look for abrasions to the sheath. A little fuzzing on the sheath is normal, and nothing to be worried about. While the sheath provides protection, a rope’s main strength is in the core. If you can pinch a small bight of rope together, it means the core is damaged, and the rope should trimmed or retired.
Typically, just your sheath will get fuzzy. A sheath that is only slightly fuzzy is fine. A very fuzzy sheath might be getting thin. Some climbers will wait until they see the core strands popping through the sheath before they decide to trim their rope. My personal opinion is to err on the side of safety; whenever I think that it might be time soon, I do it then.
Another way to recognize a damaged rope core is by pinching a bite of rope between your thumb and forefinger. Good ropes have rigidity that makes it difficult to press a bite of rope together. However, if you can pinch the rope easily, so that both sides of the bite press together easily, and the rope just feels soft in that one spot, then that indicates a damaged core.
Healthy vs. damaged rope.
The problem with simply just cutting your rope with a knife is that the sheath will creep up the core, you’ll be left with a big mess of core strands sticking out of the end of your rope, which will make tying knots and pulling ropes difficult if not problematic. Instead, the idea is to suture the cut rope using athletic tape and a lighter.
First, choose the spot you want to trim. It’s best ask your partner for help when trimming your rope. Have your partner hold the rope taught while you apply, as tightly as possible, two or three wraps of athletic tape above the part you want to cut. Use a pocket knife and saw through the rope right next to the tape. The tighter your partner keeps the line, the cleaner the cut will be.
Now, use a lighter to melt the cut nylon so it doesn’t unravel. Singe it until it’s black and kind of melted over the athletic tape. Keep your fingers away, let it cool, and you’re good to go.
Kevin Chartier sport climbing in Big Cottonwood Canyon, Utah