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Durability, NNormal, and Our Rating System
When we noticed that NNormal’s Tomir 02 shoe scored a 2.5 out of 5 in our sustainability rating system, we wondered whether we were missing something. NNormal claims its other shoe, the Kjerag, is built to last over 1350 kilometers (about 840 miles)—double the distance of your average trail running shoe. And NNormal’s marketing is all about sustainability, but its Tomir 02 shoe (reviewed here) didn’t seem to live up to its lofty mission. NNormal’s sustainability claims hinge on one key factor we don’t account for: durability.
In our sustainability ratings, we dive deep into every material and process used to make each piece of gear we review, evaluating products and companies holistically. We use multiple categories to ensure we capture a wide range of factors that contribute to a company’s sustainability. Neither the Tomir 02 nor the Kjerag feature recycled or Bluesign materials, and the brand doesn’t use recycled packaging or produce an impact report. Other shoes that we rate highly in sustainability include the features lacking in the Tomir and Kjerag, and those brands also tend to have transparent data on their annual emissions reduction efforts, showing a commitment to sustainability across their businesses. NNormal’s site states, “The fewer products we wear out and replace, the lower the impact on our shared planet.” While NNormal stresses that durability is sustainability, we think there’s more to the equation.
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Longevity
Choosing durable outdoor gear and keeping it in use for longer is one of the best ways to reduce environmental impact. Our proprietary longevity rating assesses factors like overall build quality, materials, fabric denier, component durability, and real-world performance. A green check indicates that we expect the product to be long-lasting relative to its peers, a yellow check mark indicates average longevity, and a red X indicates a product that may have a limited lifespan.
Recycled Materials
Recycled materials are prevalent in outdoor gear, with nylon, polyester, wool, and down among the most common, but the composition varies widely. A green check mark indicates the product is made with a substantial amount of recycled materials (100% recycled or the core fabric that makes up most of the product is recycled), a yellow check means it contains a moderate to small amount of recycled materials, while a red X means there are no recycled materials in the product.
Bluesign Approved
Bluesign Technologies, based in Switzerland, operates a third-party textile management system that ensures materials are manufactured to strict environmental, chemical, and worker safety standards. A green check mark indicates a product is either a Bluesign Product (contains at least 90% Bluesign-approved fabrics and 20-30% Bluesign-approved accessories) or features a significant amount of Bluesign-approved materials. A yellow check mark means it uses some Bluesign-approved materials but less than the aforementioned category, and a red X means there are no Bluesign-approved materials in the product.
Responsible Manufacturing
This criterion evaluates a brand’s commitment to fair wages, safe working conditions, and reducing environmental impact through certifications and programs like Fair Trade Certified, Fair Wear Foundation, Worldwide Responsible Accredited Production (WRAP), and the Fair Labor Association, while also recognizing brands that manufacture primarily in the U.S. or Europe under strict labor and environmental regulations. A green check mark indicates a brand meets our responsible manufacturing criteria, while a red X means it does not.
Recycled and/or Reduced Packaging
Packaging can add significant waste to outdoor gear purchases, so many brands work to reduce its impact by using recycled materials, incorporating Forest Stewardship Council-certified paper products, and minimizing plastic and paper use. A green check mark indicates a brand uses recycled or reduced materials across all of its packaging, a yellow check indicates moderate or limited use of recycled or reduced packaging, and a red X indicates the brand does not make either of these efforts.
Resale and/or Recycling Services
Resale and recycling programs help keep outdoor gear in circulation longer and out of landfills, ranging from trade-in resale platforms that offer store credit to take-back initiatives that recycle products at the end of their usable life. A green check mark indicates a brand offers both resale and recycling programs, a yellow check mark indicates it offers one or the two, and a red X indicates it offers neither.
Carbon Footprint Tracking
This criterion evaluates whether a brand measures, reports, and works to reduce its greenhouse gas emissions using established frameworks such as the Higg Index, Greenhouse Gas Protocol, or The Change Climate Project. A green check mark indicates a brand publicly reports greenhouse gas emissions data, sets clearly defined reduction targets, and uses established tracking frameworks such as Higg or The Change Climate Project. A yellow check mark indicates the brand tracks emissions and outlines reduction goals but provides limited data, lacks science-based verification, or does not clearly report progress. A red X indicates the brand does not appear to track greenhouse gas emissions or provides so little information that its efforts cannot be verified.
Annual Impact Report
Annual impact reports provide transparency and accountability by outlining a brand’s sustainability efforts across areas such as material sourcing, greenhouse gas emissions, waste, water use, supply chains, and packaging. A green check mark indicates a brand publishes a detailed, brand-specific impact report that closely aligns with our sustainability criteria and leaves little room for ambiguity. A yellow check indicates a brand provides some relevant sustainability reporting but lacks detail in key areas or is covered only briefly within a parent company report. A red X indicates a brand does not regularly publish an impact report.
What Do We Mean by Durability?
Let’s take a step back and talk about what durability is. When you buy gear, you expect it to last. You don’t want hiking shoes that tear in the upper within a month of running in them or a pair of ski pants that soak through after a few days at the hill. Durability comprises both the duration a product is usable and the condition in which it lasts.
Some durability failures are minor, like a small nick in a shoe’s outsole, while others are major, like the complete loss of midsole cushioning. We can expect that most products will break down over time, but it’s difficult to predict a catastrophic failure leading to a product’s end of life. Some won’t ever truly fail despite gradual degradation. Some products are repairable, and others are not.
A huge unknown in the durability equation lies in consumer use and care: The person who uses their shoes to hike a 200-mile, off-trail route is likely to see different deterioration patterns than someone who road-runs 200 miles in the same shoes. And if you’re like professional runner and NNormal ambassador CJ Carter, your shoes are poised to deteriorate even faster. He explains, “I run on limestone and sharp granite. And I use my trail runners for light climbing and mountaineering.” These unknowns of consumer use make it challenging to definitively say that one product is more durable than another.
Where Durability Meets Sustainability
Carter has tried both shoes NNormal makes—the Tomir 02 and Kjerag shoes. He’s had great experience with both. “I've been training for mountaineering and running since I was a teenager, and I regularly go through three or four pairs of shoes a year,” he says. “Now, I still haven't gone through one, and the repairability factor is huge.”
Although I’m no pro runner, I relate to Carter’s past struggles—I seem to destroy trail runners. I often run in them over 40 miles per week and frequently subject them to scree-skiing down mountain passes and long days of off-trail missions. I try to buy sustainably and use my shoes as long as possible, but eventually, they reach their end of life. My trail of worn-out shoes has been donated, recycled, or, in most cases, consigned to a landfill, whether I sent them there or not—twenty billion pairs of shoes are produced annually worldwide, and 95% of those shoes are disposed of in a landfill. Few companies recycle used shoes because they’re often made from many blended materials that cannot be recycled. Because the outdoor industry lags in developing comprehensive end-of-life solutions for gear, buying fewer shoes equates to producing less trash.
NNormal, however, is one of a handful of shoe brands with its own recycling program. Its website states that the company will take any gear from any brand for recycling or repurposing. However, it does not say how much of each shoe actually gets recycled, is destined for the trash, or if the company simply stores the shoe until the technology is there to recycle blended materials. While recycling programs are an important step, they are limited in their capacity to give materials new life effectively. What’s not limited is simply repairing products to extend the life they already have. In Europe, NNormal offers a host of comprehensive repair services in conjunction with cobblers across the continent (they hope to expand their network to the U.S. in 2025). It comes back to simple principles: reduce, repair, recycle—in that order.
Related to the idea of waste reduction is emissions reduction. Every piece of gear has a carbon footprint associated with its materials, production, and transportation. NNormal estimates that the footprint for its Kjerag and Tomir 02 totals 7.5 kilograms, or 16.5 pounds, of carbon dioxide emissions per pair of shoes. Multiply that by the number of shoes you’re buying annually, and it’s quite a heavy footprint if you’re buying multiple pairs. Typically, trail running shoes last 300 to 500 miles. NNormal’s site states that Kilian Jornet, the site’s founder and one of the world’s best mountain athletes, made his first pair of Kjerag trail runners last twice as long—over 800 miles. Carter has thus far logged over 600 miles on his Kjerag runners and over 250 miles on his Tomir 02s. Both pairs, he says, are still going strong. While it’s obvious that fewer NNormal shoes per year means a smaller footprint and fewer emissions, it’s worth keeping in mind that shoes made from competing brands with recycled or Bluesign-approved materials would likely have a smaller initial carbon footprint.
Repairability as Durability
While gear recycling programs improve the circularity of the supply chain, it’s also important for brands to design repairable gear and offer easy-to-use, comprehensive repair services. When gear isn’t designed with repairability in mind, minor failures can severely shorten the product’s lifespan. NNormal excels in repairable design, only producing shoes that can be resoled when the outsole wears out and that use patchable ripstop upper materials. In Europe, the company partners with cobblers who can pull the sole of a shoe off and replace its Vibram Litebase rubber as needed. NNormal plans to launch this repair program in the U.S. in 2025.
What Influences the Durability of Your Gear?
You might be wondering what qualities make a product more or less durable. We can make predictions about a gear’s durability by analyzing its materials, construction, potential failure points, and repairability. But some of these factors are more difficult to predict than others.
There are several ways to test a material’s durability, from long-term gear testing to laboratory experiments. Generally, materials made with high-denier fibers are stronger and more resistant to wear and tear than lower-denier fibers, thanks to their greater weight and thickness. Ripstop materials can also resist tearing better than their traditional counterparts due to additional reinforcement in the material’s weave. Expanded polytetrafluoroethylene, also known as Gore-Tex, can outlast counterparts in water resistance as a result of its high hydrostatic head rating. Ultra-high molecular weight polyethylene, more commonly known as Dyneema, is fifteen times stronger than steel per weight and incredibly abrasion-resistant. Matryx upper materials are becoming more common in shoes and are known to hold up better than traditional uppers. While these materials are often more durable than others, products made with them can still fail due to poor construction, shoddy seams, or other less durable materials used in the product.
NNormal uses a Vibram Litebase outsole in the Kjerag and Tomir 02 shoes. The Litebase compound is long-wearing and, more importantly, repairable. The shoes’ upper is made of abrasion-resistant monofilament polyester and TPE and is craft-stiched to the midsole, which NNormal says offers extra durability. After over 600 miles, Carter has torn the laces of the Kjerags and has gotten a few small holes in the shoe’s upper while climbing in them. But the lugs are still intact, and there are no visible signs of collapsing in the midsole.
Overall, no single test will tell you how durable a product is. While gear testing is a great method of learning about a product, it can be subjective and user-dependent. And laboratory tests don’t always reflect what a piece of gear goes through in the wild. For example, you can perform tests for abrasion resistance and water resistance, but you can’t predict exactly how your waterlogged trail runners will hold up after a week of running through the desert during a storm cycle.
Tradeoffs Between Ultralight Materials and Durability
Notably, durable materials come with tradeoffs, including that they’re often heavier. As ultralight gear becomes increasingly popular, sacrifices in durability are made for weight savings. Companies and consumers alike balance the desire for lightweight gear with the desire for gear that will last over time. It’s worth remembering that ultralight gear can be fairly durable, so long as it’s properly maintained.
What Role Do Consumers Play in the Durability Conundrum?
Every consumer uses their gear for different pursuits—and some use cases are harder on gear than others. Running on sand, for example, is more likely to degrade your outsole than running on pavement. Additionally, some users care for their gear better than others. Arc’teryx estimates that correct product care can extend garment life by an impressive 32%. While one person might leave their shoes sweaty and damp in the car for weeks, another might dry them out and alternate with another pair to allow the midsole foam to decompress between runs.
Furthermore, each person’s tolerance for wear on their gear is different. For this reason, a durability failure might lead one person to throw away their product, while another might keep it in rotation for years to come. The person willing to wear a patched-up puffy has a higher tolerance for wear than someone who decommissions their jacket at the sight of a first tear. That said, some durability failures are more consequential. For example, running in shoes that have lost their support can cause injury. Climbing gear that has passed its usable life can be a safety hazard. There are a variety of legitimate durability failures that might prompt someone to retire a piece of gear. In general, developing a higher tolerance for inconsequential wear and a willingness to continue using repaired gear with cosmetic or minor damage is a part of being a sustainably-minded consumer.
Some gear can be repurposed over time, especially if it is built to be serviceable. Referring to the life of his Kjerag shoes, Carter said, “As soon as you lose that rocker shape, I turn my trail runners into an approach shoe or something else.” Repurposing the shoe works if you can resole it—but it doesn’t work as well if a shoe isn’t repairable. While these services are becoming more common in the outdoor gear world, not all gear is designed to be repairable. And users often don’t know about the services available or can’t wait several weeks to months to get their repaired gear back. The bottom line is that repairable gear can last much, much longer than something durable but unusable once it begins to degrade. However, getting the repairs is an aspect of durability that is entirely within the consumer’s hands.
So, Does Durability = Sustainability?
We agree with NNormal that durability can be an important factor influencing the sustainability of your product. But durability isn’t necessarily an intrinsic quality in a product—it’s hard to truly say that one piece of gear is more durable than another in all use cases. Because of the dynamic nature of durability, it’s not possible to accurately integrate it into our sustainability ratings without highly replicated, long-term testing and a life cycle analysis of each product. What we can say, however, is whether a company will repair your gear or attempt to recycle it at the end of life—and you can read our gear testers’ durability analysis and decide for yourself about the quality of a product. The criteria we use in our sustainability ratings are associated with product lifetime but might not give you the full picture on their own.
Do your research on what companies make long-lasting products and offer repair services, and see how long you can keep your gear in rotation. When it’s time to retire your gear, research your options; if it’s possible to donate, repurpose, or recycle your product, you might give it another life.
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