Resling Cams: The Definitive Guide to DIY & Pro Services

Imagine you’re racking up at the base of a long-awaited climb. The air is crisp, the rock is calling your name. As your hand closes around an old, trusted cam—one of your go-to spring-loaded camming devices (SLCDs)—you notice the sling looks faded, maybe a bit fuzzy. A flicker of doubt crosses your mind: Is it still safe? That moment of uncertainty is where true mountain sense is forged. It’s the pause that separates the hopeful from the competent. This guide transforms that doubt into decisive action, providing a definitive roadmap for cam maintenance, specifically how to understand, inspect, and service your cams, ensuring every piece on your rack is one you can trust with your life.

This journey will teach you to see the unseen expiration date on your gear, to understand why time, sun, and wear are the silent enemies of your cam slings. You will learn to inspect your equipment like a seasoned pro, mastering a systematic process for both the textile and mechanical parts. We will draw a clear line between professional reslinging services—the standard for safety—and a temporary DIY resling for emergencies only. Ultimately, you will walk away with an actionable framework to confidently manage the entire lifecycle of your cam slings, turning anxiety into the confident instinct of a responsible climber.

Why is a Cam Sling’s Lifespan So Critical to Understand?

To trust your gear, you must first understand its limitations. The vibrant, supple sling on a brand-new cam is a marvel of material science, but it’s not immortal. This section breaks down the fundamental science behind textile degradation and the non-negotiable safety rationale for sling replacement. This is the foundational knowledge you need to make every subsequent decision correctly.

What factors cause a cam sling to degrade?

The forces that weaken your cam slings are often invisible, working slowly and silently over time. The primary antagonists are UV radiation, abrasion, and chemical contamination. Sunlight is a primary enemy; its UV rays relentlessly break down the polymer chains in nylon webbing and Dyneema fibers, leading to a significant, often imperceptible, loss of strength. Abrasion/rubbing is more obvious—the mechanical wear from dragging over rock surfaces slowly severs outer fibers, creating that tell-tale “fuzzy” appearance that indicates a reduction in the material’s cross-section and strength. Finally, and perhaps most insidiously, is sling contamination. Contact with common chemicals like solvents, battery acid, or even insect repellent can cause catastrophic, invisible damage to synthetic fibers, rendering them dangerously weak.

Beyond these primary threats, the simple act of using your gear contributes to its decline. Repeated loading and unloading cycles, constant flexing, and the infiltration of microscopic dirt and grit all contribute to a gradual, cumulative loss of strength over the sling’s service life. The two primary materials, Nylon and Dyneema (also known as Spectra or UHMWPE), degrade differently. Nylon is more susceptible to UV damage and loses significant strength when it absorbs water, while Dyneema is more vulnerable to heat and strength loss from repeated flexing, especially when knotted. This is why the industry, led by manufacturers like DMM and Wild Country, has adopted widely accepted retirement criteria: a maximum 5-10 year lifespan from the date of manufacture, regardless of use history or even lack of whips. It’s a hard stop designed to protect you from the uncertainties of a material’s hidden history.

Understanding these invisible forces is the first step. Now, let’s translate that knowledge into a tangible skill: how to read the story of wear written on your gear. For more on this, the official UIAA standard for mountaineering slings provides the foundational testing criteria that underscore the critical nature of material integrity. This specific discussion also fits within the broader topic of understanding the full climbing gear lifespan.

How Do You Perform a Definitive Cam Inspection?

A proper visual inspection is a deliberate, systematic process. It’s a conversation you have with your gear, using your eyes and hands to uncover its secrets. This section provides a practical, step-by-step guide to thoroughly inspecting a cam, covering both the textile and metal components to make a holistic safety assessment.

What are the visual and tactile warning signs on a sling?

Your visual inspection begins with a hunt for the obvious and the subtle. Look for areas of Excessive Fuzziness & Thinning, especially where the nylon sling or dyneema sling passes through the hardware or frequently contacts the rock. Meticulously inspect the sling’s entire surface and its edges for any Cuts, Nicks, and Tears. Remember, even small rips or tears in a high-modulus material like Dyneema can dramatically reduce its ultimate strength. Note any significant Discoloration and Fading, as this is a tell-tale sign of UV degradation, while any unusual, localized discoloration could indicate chemical contamination. Finally, look for Glazed or Melted Spots. These hard, shiny patches indicate heat damage, likely from rope friction, which makes the fibers brittle, weak, and untrustworthy.

Next, you must use your sense of touch. Slowly run the entire length of the sling through your fingers, feeling for any inconsistent feeling. Soft/hard spots can indicate heat damage or internal fiber damage, respectively. Any sling that feels stiff, crusty, or brittle has likely suffered significant UV or chemical damage and is no longer safe. Finally, pay close attention to the Bar Tack Stitching on sewn slings. The stitching must be fully intact, with no loose, frayed, or broken threads. This is the structural glue holding it all together. When performing this tactile check, there is one uncompromising principle of climbing gear maintenance: “When in doubt, retire it.” Your life is not worth the gamble.

Pro-Tip: To reveal hidden damage, especially small nicks or cuts on the edges of a sling, bend it sharply into a tight radius over your finger. This forces the outer edge to expand, making even minor fiber damage more visible.

A sound sling is useless on a compromised cam. Before deciding to resling, you must first judge the integrity of the hardware itself. The principles we follow are reinforced by expert-level guidance on technical information on equipment care from industry leaders like Petzl, and they are a key part of holistic hardware and harness maintenance.

Is the cam’s hardware still safe and functional?

Your structural integrity check starts with the cam lobes. Inspect them for cracks, especially around the axle holes, and look for significant gouges or “witness marks”—flat spots that indicate high-impact fall and significant cam lobe wear. Next, check the axles themselves. They must be perfectly straight. A bent axle is a clear sign of severe loading, impairs function, and is grounds for immediate retirement. Examine the main body cable for any frayed or broken wires, sharp kinks, or permanent bends, and ensure any protective sheathing is fully intact. Don’t forget to check the condition of the trigger wires; while often replaceable with a trigger-wire repair kit, frayed wires can signal heavy use.

With the structure confirmed, check its function. The Trigger Action should be smooth and consistent, with the springs providing snappy response. The lobes must snap back instantly and evenly when released. Sticky cams with a gritty or slow action require a thorough cam cleaning. Start with hot water, liquid dishwashing detergent, and a stiff-bristled toothbrush, then use compressed air from a compressor to dry it completely. Apply a dry, wax- or Teflon-based lubricant like Metolius Cam Lube or Lock-Ease, as recommended by experts like Jim Karn in resources such as the Crag Survival Handbook. Avoid penetrating lubricants like WD-40 or Triflow, as they attract dirt and can gum up the action. Finally, carefully inspect the Thumb Loop/Termination and cam stop area where the sling attaches. Any cracks or damage means the cam must be retired. The final verdict is simple: only a cam that passes this comprehensive mechanical inspection is a candidate for a new sling. The rigorous testing requirements detailed in the UIAA standard for camming devices validate the importance of checking for these very issues.

Once your cam has passed inspection, the path forward splits. Let’s first explore the safest and most reliable option: professional servicing. This is a crucial step in building out your first trad rack and maintaining it for a lifetime of adventure.

Which Professional Reslinging Service is Right for You?

When your cam’s hardware is sound but its sling is aged or worn, professional reslinging is the gold standard for safety and performance. This section provides a clear, comparative analysis of available cam reslinging options, helping you make an informed decision based on your rack composition, budget, and location.

Should you use a manufacturer (OEM) or a third-party service?

The first choice is between the Original Equipment Manufacturers (OEMs) who made your gear and specialized third-party services. OEMs like Metolius, Black Diamond, and DMM offer services for their own brands, providing the ultimate peace of mind that the work is being done by the experts who designed and built the equipment. Metolius, in particular, sets the gold standard; their resling service is a comprehensive overhaul that often includes cleaning/lubing and trigger wire replacement for a very low price, making it an unbeatable value for Metolius cams. In contrast, Black Diamond offers a more utilitarian sling and trigger wire replacement for their Camalots and C3s, while DMM provides a full inspection and service model. The primary limitation of OEM services is their “walled garden” approach—they only service their own gear, which can be inconvenient for climbers with mixed-brand racks.

This is where third-party specialists shine. Services like Runout Customs, Mountain Tools, and Wired Bliss thrive by offering a one-stop resling service for mixed-brand racks, saving climbers significant time and shipping costs. Each has its strengths: Runout Customs is known for a quick turnaround and broad brand compatibility; Mountain Tools is the official North American service center for DMM cams, Tricams, and even older passive pro like Hexes; and Rock and Resole made a name for themselves by developing a custom, tested resling solution for Totem cams. Regardless of who you choose, the UIAA safety label program reinforces why OEM and certified services are so reliable—they operate under stringent, globally recognized safety and quality control standards.

Pro-Tip: Before sending your cams in for service, use a small dab of colored nail polish on a non-load-bearing, non-contact part of the metal (like the side of the trigger bar) to uniquely identify your gear. This prevents mix-ups and ensures you get your trusted pieces back.

When preparing your cams, clean them thoroughly, carefully cut off the old slings yourself, fill out the paperwork correctly, and ship them securely in a box with tracking and insurance. But what if professional service isn’t an option, and a sling gets damaged mid-trip? This is where knowing how to create a safe, temporary fix becomes a critical field skill.

How Can You Improvise a Safe, Temporary Sling Replacement?

Let’s be unequivocally clear: this section addresses emergency, field-expedient solutions only. These are temporary measures to get you safely through a climb or back to the trailhead, not permanent, cost-saving alternatives to professional, factory re-slinging.

What is the safest way to attach a pre-sewn runner to a cam?

First, an absolute and non-negotiable safety boundary: never attempt to sew your own cam slings with a domestic sewing machine. Certified climbing slings use industrial sewing machines with specific thread and stitch patterns (bar tacks) to meet the 22 kN strength requirements. A home machine cannot replicate this. With that established, let’s look at field options. The most commonly discussed method, the Girth Hitch, is strongly discouraged. Independent break test data, popularized by testers like Ryan Jenks of HowNOT2 and detailed in reports from the Black Diamond QC Lab, has repeatedly shown that this hitch can cause a strength loss of 50% or more as the webbing cuts into itself under load. It creates a dangerously weak link in your safety chain.

The far superior and acceptably strong method is the Basket Hitch. This is accomplished by passing a pre-sewn runner (a 30cm or 1 foot length is common) through the cam’s wire loop or attachment point and clipping a racking ‘biner through both strands of the runner, forming a clean, redundant “basket.” The strength data is clear: a girth-hitched sling might fail around a terrifyingly low 9 kN, whereas a properly executed basket hitch has been tested on a drop tower to hold over 17.2 kN, maintaining a much higher margin of safety. The simplest temporary solution of all is the Quickdraw Method: cutting the old sling off completely and clipping a short quickdraw directly to the cam’s cable loop or thumb piece. This avoids any strength-reducing knots entirely. However, be aware of an important caveat: on some modern cams (like Black Diamond Camalots), the thumb loop is designed to accommodate a double-layer sling. A single, narrow carabiner from a quickdraw can cause pinching or damage under a significant fall. The bottom line is that any DIY solution is a temporary fix. The cam must be sent for a professional resling as soon as possible.

The method of attachment is only half the equation. The material you choose for that temporary runner—Nylon or Dyneema—has significant safety implications of its own. The data from research on knotted sling configurations provides critical scientific analysis on this topic, and a deep understanding of knots like the water knot or double fisherman’s knot (used for making loops from webbing or accessory cord, respectively) is essential for any climber looking to be mastering essential climbing knots.

Conclusion

The decision to trust a piece of gear begins and ends with rigorous, honest inspection. A compromised cam, whether from a bent axle or a cracked lobe, must be retired immediately, regardless of the sling’s condition. For any mechanically sound cam with a worn or aged sling, professional reslinging is the only recommended permanent solution for guaranteed safety and certified strength. Field fixes, like attaching a pre-sewn runner with a basket hitch or a quickdraw, are acceptable emergency measures, not cost-saving replacements; the dangerously weak girth hitch should always be avoided. When you consider the peace of mind that comes from restoring a critical piece of life-support equipment, the small resling cost—typically between $7-$20 per cam—is an insignificant price to pay. Act decisively.

Share your own experiences with cam maintenance or ask any lingering questions in the comments below to help build our community’s collective knowledge.

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