As climbers and climbing-gear buyers, we are accustomed to wading through marketing claims, weeding out hearsay, and determining the facts on our own before we act. Is that carabiner really just 29g? We’ll simply put it on the scale and know the answer. Do these ski bindings collect ice and snow like I’ve heard? I’ll demo a pair and find out before I buy them. This tendency toward skepticism is healthy, and helps keeps us safe while climbing and skiing. It also means that when I have an initial impression, or glean what is thought to be “conventional wisdom” I often try and test such beliefs, rather than assume accuracy.
Guides and multi-pitch climbers have dealt with elbow and shoulder issues for years as a result of bringing up second and third climbers and fighting to get ropes through the anchor. Could the options for solving this problem be tested once and for all? I hoped to put the conjecture to rest and actually quantify the difficulty of belaying from above. I recently heard several climbers complaining about their problems with pulling rope through the Edelrid Mega Jul device while hanging it in guide mode to belay up a second climber. These climbers expressed appreciation for the device’s locking-assistance, but said that it was too much work to pull rope through the device as it hung from the anchor. Others chimed in to say that their upgraded belay device model was better than prior iterations, or their belay carabiner was smoother than the one used by someone else, and saved their elbow regardless of the device. In this article, part 1 of a 2-part series, I look at hanging belay devices, in combination with different ropes and carabiners. But as I was testing these devices, I realized that the claims made about ropes (length, weight) also seemed far from iron clad, yet would be easy to assess with the right tools. I’ll be looking at those measurements in the second article. As my dad always liked to say, we are each entitled to our own opinions, but not to our own facts. And the forces needed to of pull rope through different belay devices? Those are facts.
- I began my test by borrowing a few ropes, devices, and a hanging scale from other friends and climbers who live nearby. I was fascinated to note differences in lengths of up to 5 meters between between ropes theoretically of the same length, and in measuring out 2 different 80m ropes, 4 different 60m ropes, and 4 different 70m ropes, the closest I came to a match was with 2 different 60m ropes which were only 30cm different in length. I saw no other 2 ropes which were thin 1 meter of each other, and I also saw no consistency within brands, for having all relatively longer or shorter ropes. I am going to follow up with these differences in weight and length in a subsequent posting. For my tests, I ended up with more than a half-dozen different rope brands and diameters, but settled on three different models for the test: a Tendon Master 8.9mm, a Petzl Arial 9.5mm, and a Bluewater Pulse 9.9mm.
- For the all-important belay carabiner, the one which the rope runs around and makes contact with while the device is hanging, I settled on the original Petzl Attache. This is a classic “round-stock” carabiner. In some initial tests I substituted other carabiners with a less rounded cross-section, and found that there was a measurable increase in force required to pull in rope. This difference was noticed regardless of the device chosen.
The Belay Devices
- For the belay devices, I had a Trango Cinch, Petzl Gri Gri II, Petzl Reverso, Petzl Reverso 4, Edelrid Mega Jul, CAMP Ovo (belay plate), and the Cassin PIU 2. I also later tested a Mammut Smart Alpine (not shown in the graph) and the values were similar to the Edelrid Mega Jul.
- I hung a scale from the top of my freezer, and would “zero” out the weight after clipping on the device, the carbiner, and feeding the rope through so that there was a loose pile of cord at my feet, the rope ran up and through the device, as if belaying a second climber, and then ran back down to the ground. I would then steadily pull rope through the device on the brake strand, and note what was the maximum force exerted on the scale. In other words, how hard did I have to pull?
I tried to make each pull of rope uniform and smooth, bending my arm at the elbow and not violently yarding downward on the scale. I would pull armloads of slack through each device, with each rope, and note an average maximum value for the various hardware combinations. At the end of the day, the absolute values (expressed here in kilograms) are not as meaningful as the relative differences among devices and rope sizes. Pitch length, rope drag on a pitch, rope stiffness, and belay carabiners all play major roles in determining hard hard you are working to get slack in through each device in a real scenario, but the fundamental takeaway is that even controlling for each of these variables (as I was in my kitchen) there is a wide range of difference in effort required to belay. Some surprises, such as the difficulty of the newer models of Reverso relative to the original, and the overall ease of the Mega Jul, made me glad I hadn’t just trusted the gut reactions of others. It was also interesting to see that some devices had definite “sweet spots” where a thin-diameter rope would pull through with ease, while a rope just slightly thicker would be a major pain to belay with. I am going to investigate the claims of weight, diameter, and rope length in an upcoming post, but at the very least it is worth noting that simply because a rope is labelled as having an equal (or thinner) diameter than a different model, there might be little difference in terms of how the tool ropes actually feed through a device or handle on a pitch.
Even without a fancy scale or half-dozen devices to test, there is a great in-the-field version of this experiment which would allow you and your partner to choose the best device for your team’s multipitch leader to use that day. Hang one of your devices from a tree limb in guide mode, thread the rope through the device, and then clip an empty backpack onto the “brake” strand of the rope, which you would be pulling on to belay the follower. Start filling the pack with cams, draws, and small pieces of climbing gear, until its weight begins to pull down on rope. Now leave the pack’s weight the same, but trade out the belay devices and re-hang the pack. If you can remove some gear from the pack and it will still pull down on the brake strand, you’ve just found a reason to use this second belay device for the leader, and you can re-use this test to find the smoothest carabiner as well. Folks may think you look strange hanging your pack and belay devices from a tree to start your day, but that’s just another’s opinion. And they’d be entitled to it.