Ascender Safety 101

       Ascending Rappel Ropes 101

       Autoblock Misuse (ATC-Guide)

       Avalanche Safety

       Belay School - Why Dynamic Matters

       Can A Hot Belay Device Melt My Slings?

       Carabiner Off-Axis and Tri/Quad-Axial Loading

       Choosing the Right Carabiner

       Common Belay Screw-ups

       Connecting Two Slings Together

       Daisy Chain Dangers

       Dangers of Rope Worn Carabiners

       Dangers of Worn Lowering Anchors

       Do Ropes Need to Rest Between Falls

       Draws in a Gym

       Extending a Cam Sling

       Fall Factors Explained

       Full Strength Haul Loops

       Gear Doesn't Last Forever—Crampons

       Gear Doesn't Last Forever—Ice Tool Picks

       Gear Doesn't Last Forever—Slings & Draws

       Girth Hitching a Stopper

       How Sketchy Is a Sharp-Edged Carabiner?

       How Strong are Himalayan Fixed Lines?

       How Strong is the Spinner Leash?

       How To Belay, Part 1

       How To Extend a Rappel Device

       Knot Passing 101

       Rappelling - Climbing's Diciest Business

       Re-Slinging Cams

       Rethinking the Double-Loop Bowline

       Retiring Old Ropes

       Sharpie for Marking the Middle of a Rope?

       Sling Strength In Three Anchor Configurations

       Spectra versus Nylon

       Spotting for Bouldering

       Surviving Bad Weather on El Cap

       The Dangers of Modifying Your Gear

       The Dangers of Short Static Falls

       The Electric Harness Acid Test

       The Skinny on Super Light Ropes

       Top Roping is Not So Safe

       To Screamer Or Not To Screamer

       Via Ferrata

       Weakness of Nose-hooked Carabiners

       What is the Safest Rappel Knot?

       Worn Belay Loops and Retiring a Harness

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Climb Safe: The Dangers of Modifying Your Gear

By Kolin Powick

The following article is courtesy of Black Diamond Equipment.

Here at BD we are all a bunch of tinkerers. We're constantly tweaking our gear or cobbling together prototypes, trying to make them lighter and perform better.We fiddle with gear, test it in the lab and take it out into the field.Therefore, when people want to customize and modify our products, we understand.

But there is a reason that we have a blurb in all of our instructions for use stating, "do not modify this product in any way." It's not that we're trying to limit creativity. It's because we've gone through painstaking efforts to ensure that our products meet all necessary strength and certification requirements, and behave how they are intended. We need to consider typical use, misuse, and abuse. We need to consider ultimate strength, durability, manufacturability, ratings and certifications. The end result is a product that we're psyched about and meets all external and, just as importantly, internal requirements we put on it.

When people modify their gear, they may unwittingly be changing a critical design or strength feature.

When I'm out climbing I see some of the mods that people have done, and I cringe. I also get lots of emails asking if I recommend a particular tweak, change or modification to a product. A few examples and my immediate thoughts:

  • Drilling holes in ice tools: People do this to add leashes, add makeshift pommels, or allow better use as a dead man. Our ice tool shafts are burly—they pass all CE requirements. But by drilling a hole, specifically in a high stress area, you can significantly decrease the ultimate breaking strength and/or fatigue life. Yes, I've seen drilled ice tools break at a hole someone had drilled.
  • Drilling holes in belay devices to make them lighter: Do you really want to start jeopardizing the integrity of one of the most critical components in the belay chain? Many, like the ATC-Guide and ATC-XP, already have the sides cut out for those weight conscious folks.
  • Adding an additional belay loop to your harness: Belay loops are burly strong. You don't need a belay-loop backup—it just adds more clutter and opportunity to mis-clip, and have weird loading on your belay loop. Check out this previous QC Lab post here: Worn Belay Loops and Retiring a Harness. Sure, some harnesses, usually big wall harnesses (like our Big Gun), come with two belay loops. That's so you can keep the excessive amount of gear you're using nice and organized—NOT for you to belay using two belay loops.
  • Adding additional gear loops to your harness: Sewing into a structural component of your harness is not recommended. If you want more gear loops, get a different harness.
  • Modifying one manufacturer's picks to fit in another's ice tools: The pick/tool interface is pretty critical. Tools are tested as a system and using a pick that isn't designed for that tool compromises the entire system.
  • Using aluminum rear rails to save weight on steel crampons: The risk here is even though it's a rear crampon rail, the aluminum down points aren't nearly as durable as steel and will quickly wear to being too dull to do you much good. Weight savings always costs something, and in this case it's performance.

These are just a few random examples among many we've encountered, but we decided to choose three instances of modification that we've seen come up lately and test them here in the lab. Many modifications fall under the category of "not a good idea," but the examples below are ones we think might actually be legitimately dangerous in situations of consequence.



Open-loop replacement.This one has been covered before but it's worth revisiting. Re-slinging Camalots with open loop or extendable slings—one of our most frequent questions. Could we replace our slings with either an open-loop sling/runner or an extendable sling? Sure. But we don't, and we don't recommend it. Open loop slings, narrower spectra slings or extendable sling configurations result in a higher likelihood of tweaking your thumb loop under normal falls, and in the worst case, cutting the slings at lower than originally intended loads.

Older-style Camalots had an open-loop sling; C4s, C3s and X4s have a sewn sling that is double thick where it contacts the wire cable of the cam. This is for two reasons:

1) Ultimate Strength

These slings are designed to attain the strength ratings we desired. During loading, the cable thumb loop pinches down, and in-effect eventually cuts through a single thick sling at between 9kN-10kN. The double thick sling distributes the load, and allows the sling to meet higher load—up to 14kN.

2) Tweaked thumb loops

During a loading situation, the single layer of webbing isn't firm enough, and the thumb loop pinches down resulting in a slightly kinked cable. The double-thick sling alleviates this.

The double thick sling distributes the load, and allows the sling to meet higher load—up to 14kN.Tweaked thumb loop.













Double loop replacement (aka, extendable sling).Lots of people seem to think an extendable sling on a cam is a good idea. There are three reasons why we don't use extendable slings on our cams and why we don't recommend replacing BD cam slings with extendable slings:

1) Extendable slings are bulky and just make a mess of your rack. Plus, if you look at a typical extendable cam sling vs. a non-extendable, it's only about 1 carabiner height longer. Use a shoulder length sling when you want to extend the sling and avoid cams walking and/or rope drag.

2) When used in extended mode, they result in lower strength values than standard slings

3) Again, there is a high possibility of tweaking the cable in the event of a fall



Not all manufacturers use the same diameter of toe and heel bail wire, flats on the ends of the wire, or holes which they fit into on the front and rear rails. Use a smaller wire with the larger hole, and the crampon won't meet the CE and UIAA strength-of-bail-attachment requirement of 1kN. More importantly, you risk the possibility of the bail popping out mid-pitch.

This test involves pulling or prying the bail wires away from the crampon rail. Check out the following link to see how we set up the test:

[Note: test performed on BD rails. EN893 requirement (section 4.3.3 transverse strength bails) = 1000N (224.8lbf) proof load.]

The above data shows that using mix-matched bail wires and crampon rails can result in it being pretty darn easy for the bails to pop out. Not ideal.



Word on the street is that some folks believe ice tool tethers are capable of arresting a fall. News flash: they're not, and that's not what they're for. It seems that I've already been through this, however, I've still had a few people ask if they replaced the attachment points with "full-strength" biners, would that cut it? No.

Click to zoom. I've even caught wind of some creative folks out there wanting to incorporate a "Screamer" into their tether system, so it reduces the load, acting more like a via feratta. Still not a good idea. Don't believe me? A few of the crew headed down to the drop tower to demonstrate. We connected a spinner leash to two ice tools and rigged up a Screamer to the mass in our drop tower and did a few realistic drops—representing either one or both arms of the tether taking the load should your feet pop.

Therefore this showed that even with an energy absorption system in the mix, it doesn't matter. The load generated is still high enough to break the tether. Short falls onto static material send the loads through the roof.











To reiterate for the umpteenth time. Ice tool tethers are to stop your leashless tool from falling into oblivion should you drop it. They are NOT designed, tested, nor intended to catch you should you slip and fall.


Bottom Line

Any time you modify your gear you're potentially affecting something that you may not be aware of. Cutting off some excess straps off your pack to save some weight is one thing, but modifying PPE (personal protective equipment) is another. Most gear manufacturers have gone through great lengths to provide the equipment in the way it was intended, so it's likely better to just leave it that way.

Climb Safe,



Kolin Powick (KP) is a mechanical engineer hailing from Calgary, Canada. He has over 20 years of experience in the engineering field and served as Black Diamond’s Director of Quality for over 11 years. He is currently their Climbing Category Director. If you have a technical question for KP, please email him at and he will TRY to respond.

To help make more climbers safer climbers, Rock and Ice has teamed up with Black Diamond Equipment to present the information here.

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