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Runners are a very particular breed of athlete. Always on the hunt to improve their running time and tempo, they tend to stick to what works, especially when it comes to their shoes. I know this first-hand from my experience training for the New York City Marathon and you could not pay me to run in a shoe other than my tried and true, and certainly not an eco-friendly option like Allbirds. But now, I’m happy to say that the tides are turning for runners and athletes when it comes to activewear.
Today, Allbirds releases their most technical running shoe, the Tree Flyer, which is a culmination of the brand’s three passion pillars: sustainability, innovative manufacturing practices and high performance footwear. And developing a high quality running shoe that athletes and hobby runners alike would want to wear is one aspect that the Allbirds team knew was critical.
“As a former professional soccer player, I know that the bar is really high for running shoes,” said Tim Brown, co-founder of Allbirds, during the launch event. “So I knew that this product had to work. People don’t want to buy a sustainable product, they want to buy great products, but for a product to be truly great today, it must also be sustainable. We’ve brought natural materials to the form and we’ve proved that what’s basically been told to us is an impossibility — that natural products can make better performance products.”
And ensuring that the shoe would indeed be high performing to earn its spot among the best running shoes is something that Brown and his team took incredibly seriously — and to a large degree, through trial and error. Throughout the Tree Flyer’s two year development — which, considering the brand has been around for six years, is a considerable time investment — Allbirds tapped 115 runners to test each iteration of the Tree Flyer and report back on its look, feel and performance. Their feedback, gathered from running more than 7,000 miles in the shoes, guided each refinement and new update, until they finally got it just right.
“This is the best shoe we’ve ever made, in my opinion,” says Brown, who admitted that it was a challenging journey, but “a true labor of love” that he believed in deeply.
What is the Allbirds Tree Flyer Shoe?
Allbirds Tree Flyer shoe is a brand-new shoe designed specifically for running longer distances. It combines the comfort and sustainable materials that Allbirds is known for with the technical details needed for a great running shoe. Introduced as the brand’s most technical shoe to date, the Tree Flyer is composed of castor beans, which are the primary performance ingredient, versus relying on oil-based raw materials made from fossil fuels.
One of the Tree Flyer’s most important features is the new midsole, which is incredibly lightweight, clocking in as 30% lighter than SweetFoam, to provide a serious amount of cushioning, stability and support, as well as a serious bounce effect with each step — a detail that is crucial for most runners. The flared external heel gives even more support while the toe spring eases the gait’s transition between the back of the foot to the front.
How I Tested the Allbirds Tree Flyer Running Shoe
- Product Tested: Allbirds Tree Flyer shoe
- Notable Materials: Material is made from castor beans
- Period of Testing: I tested for 10 days. I went on four 45-minute runs and spent three afternoons walking around wearing the shoes.
- Price of Product: $160
- Testing Verdict: While there’s no such thing as a universal running shoe (yet), the Tree Flyer has many attractive qualities and features and once I added the support that my foot anatomy needed, it was a pleasure to run in. To get an expert’s take on the new design, I consulted my former running coach, Yusuf Jeffers, who provided his professional opinion.
After hearing Brown and his team speak about their passion for this boundary-breaking Tree Flyer shoe, I couldn’t wait to get my hands on it and test it for myself. I was given the Allbirds Tree Flyer running shoe in a size 10.5 in bright neon orange (which just so happens to be one of my favorite colors). I went running in the shoe four times, and I also wore it walking around the city running errands, meeting friends for brunch and perusing the Brooklyn Museum. All in all, I’d estimate that I spent a total of 3.5 hours running in the shoe and 18 hours walking.
Adam Mansuroglu, WWD’s Director of Commerce, also took the Tree Flyers out for a spin.
How is the Allbirds Tree Flyer Shoe More Sustainable Than Other Running Shoes?
Allbirds was founded by Brown based on a commitment to sustainability. To create a sustainable running shoe that won’t compromise quality or performance, Brown turned to Dr. Romesh Patel, the head of Materials Innovation at Allbirds.
“We are breaking barriers on two fronts,” explained Dr. Patel at the launch event. “First is on materials. Instead of relying on materials made from fossil fuels, we’re using castor beans as the primary performance ingredient. The second is on processing for the cushioning.”
Dr. Patel explained that manufacturing athletic shoes is a “multi-step, high energy waste process,” yet his team was able to “shrink all of the steps down to a single, low carbon step” and even reused the waste which this one step created. “My favorite part is the insert circularity; we took the waste from the high-performance foam and repurposed it into another high-performance component: the external heel for extra stability.”
By working closely with the test runners and their feedback, Dr. Patel’s team was able to continue to improve and refine the sneaker “without ever losing sight of performance.”
Some of their design tweaks are surprising — the lack of a shoe tongue to customize shoe fit and the absence of stitching to keep the structure securely intact, for example — but their inclusion would have added onto the total carbon footprint, and were innovated around.
To celebrate their achievement of producing this low-carbon, sustainable running shoe, the number 9.92 — signifying each pair of shoes’ carbon footprint — is emblazoned on the back of every shoe. Considering that most other running shoes fall within the 14 or 15 kilograms range, this is indeed a feat to be celebrated.
My First Impression of the Allbirds Tree Flyer Shoe During My First Run
Like most runners, I’m very loyal to the footwear brand I’ve been wearing for more than a decade. My gait has a moderate pronation, especially on my right side, for which I wear an insole to balance out. Most runners have some kind of underlying gait or foot issue, whether they need to wear insoles, or choose a hair of sneakers with high arches, low arches, extra cushion, less cushion, and so on. I prefer a decent amount of cushion, and nearly everyone enjoys a bounce, which feels like a literal pep in your step, so I was happy about the 1.5 inch foamy bottom. The front of the shoe looked rather narrow to me, but once I slipped it on, it felt nice and roomy. Unlike a traditional running shoe which has a lot of firm structure, from the tongue to the lacing sides, the Tree Flyer was bendy, and the shoe doesn’t have a tongue at all.
Since I’d never seen such a stretchy, fabric material — or lack of a tongue — in a running shoe before, I tapped my old running coach, Yusuf Jeffers, a USA Track & Field-certified running and conditioning coach with more than 14 years of experience and trained me for the New York City marathon. “Upper construction and material affects width, durability, how well your foot fits into and is held in place by the shoe,” says Jeffers, which is dependent on a runner’s particular anatomy and gait pattern.
“Someone with a flat foot strike when running will most likely need more cushioning than a runner with a midfoot strike,” he explains. “Too much cushioning can cause a runner to bounce and displace vertically wasting energy and too little cushioning and more impact will have to be absorbed by the body.”
For the first run, I chose to use the shoe as-is, meaning I didn’t use my insole, so I could see what kind of baseline I was working with. On my 45 minute run, the shoes felt springy, soft, and mostly flexible, although the area right above the shoe tie began to rub and irritate my skin towards the end. Yet according to Jeffers, that’s totally normal. “All shoes have a period of time when they will need to be broken in and conform to your foot,” he says.
I also noticed that there is minimal arch support; I felt pretty flat-footed while wearing the shoes and about halfway through, I knew I would need to use my insole on the next test run, or if I were running a longer distance.
How the Allbirds Tree Flyer Shoe Performed During Subsequent Runs
Keeping in mind that I was still mid-break-in period, I was curious how the shoes would fare during our second outing. I took my insoles from my regular running shoes and easily popped them into the Allbirds. I was surprised that I was met with no resistance when pulling out the Tree Flyer’s insole, as with traditional running shoes, you literally have to rip it out with the stitching. And in fact, there was no stitching or glue on the insole at all to keep it secure. While it was strange at first, it makes sense, as additional fabrics and adhesives would add to the carbon footprint, and likely the reason why they eliminated the shoe tongue altogether.
The next run was more comfortable than the first, likely thanks to the insole. My springy steps felt light and actually caused me to run a little faster than normal, according to my tracker.
How the Allbirds Tree Flyer Performed During Long Walks
While the Tree Flyer was made for running, there’s something to be said about a shoe that can withstand a day of standing and walking around without triggering an achy foot. I’m happy to report that my arches felt plenty supported throughout the day, and the shoes remained comfortable. It was also while I was walking around that I noticed the pleasant breathability of the fabric that kept my foot cool.
Who Should Wear the Allbirds Tree Flyer Shoe?
There’s a wide variety of runners out there and every anatomy is unique. We hate to say it, but there’s no such thing as a universal running shoe that will be a great fit for every body, preference and running style.
That said, Jeffers says that the Allbirds Tree Flyer shoe is a fantastic fit for a few specific types of runners. “The sole looks good and very cushiony, which makes it a supportive shoe for neutral runners and those who overpronate,” he says. On the flip side though, he adds that the cushiony midsole will absorb the most impact, causing the foam to compress over time and become less bouncy.
The contours of the shoe also have specific functions to assist runners, aside from just looking cool and sleek. “The curve of the sole ensures a mid-foot strike,” he says, “which will help people who have a heel to midfoot strike balance out their stride.”
The supportive, cushioned heel is another major pro he says, before adding that the shoe sizing needs to be exact. “The top of the shoe, because of the fabric material, is expandable, meaning you can slide around in the shoe if it is too big for you; you want it to feel snug around your foot.”
Are the Allbirds Tree Flyer Shoe Worth It?
As I thought about my final takeaway, I couldn’t help but go back to the facts Brown and his team shared at the launch event. Fast fashion is a serious problem and one that is being highlighted more and more in the media and among communities. I love that this shoe has a carbon footprint of 9.92 and that it is made of castor beans. I’m in awe of the research, innovation and grit of Brown’s team to develop such a shoe, between two full years of perfecting the design, to tapping hundreds of testers to run literally thousands of miles, to the uncompromising commitment to performance. Allbirds achieved a major feat with the Tree Flyer running shoe, ushering in a new chapter in both sustainability and high performance footwear, and one that I’d bet will keep improving over time.
While I don’t think I’ll abandon my old running shoes, I will definitely continue to run in the Allbirds Tree Flyer shoe and observe, as Jeffers said, how my foot continues to conform to the shoe over time. This running sneaker may not be for everyone, especially if you’re flat footed or don’t like significant cushioning, but for those who are committed to making choices that positively impact our environment and don’t mind a little trial and error to see how you can adapt the shoe to your needs, like using an insert, then this shoe is worth every penny — or at the very least, a serious consideration.
Meet the Experts
Yusuf Jeffers is a former Division I Track & Field and basketball athlete with more than 14 years experience as a running and conditioning coach. He is certified by USA Track & Field and coached his high school team to state and national-level championships. He is a Head Coach Trainer at Tone House and Coach for Mile High Run Club, co-managing their training programs for half and full marathons. He is based in New York City.
Meet the Author
Kaitlin Clark is the beauty + style commerce editor at WWD. She’s also an avid runner. Over the last several years, she ran the New York City Marathon, as well as 20 half marathons, and is currently debating whether she has it in her to run another full marathon.