Weight: 8.37oz/ 237.3g (W7), 10.63oz / 301.5g (M9)
Allbirds are trying to solve a big problem in the running shoe world — the global trainer industry produces the same amount of CO2 as the whole of the UK, with the average pair of running shoes generating 14kg of carbon emissions during its lifetime. While the simple solution is to buy a pair of running shoes that’ll last you a long time, Allbirds is making waves in the industry by creating carbon-neutral running shoes.
The Allbirds Tree Flyer 2 is the brand’s second stab at a neutral running shoe, best suited to easy miles, HIIT classes, and gym classes. It replaces the Allbirds Tree Flyer, released last year, and has an even lower carbon footprint than the previous iteration. But how does it compare to some of the best running shoes on the market, and what kind of runner is this shoe best suited for? To find out more, I’ve been running in the Allbirds Tree Flyer 2 for the past month, over a number of different sessions and terrains. Read my Allbirds Tree Flyer 2 review below to find out more.
Allbirds Tree Flyer 2 review: Price and availability
The Allbirds Tree Flyer 2 is available from Allbirds online and in-store now. It costs $160/£150, which is the same as the original shoe, and around the same price point as other everyday running shoes, such as the New Balance 1080v13 and Asics Gel Nimbus 25.
The shoe comes in a number of different colorways and sizes for both men and women. In the men’s shoe, the Tree Flyer 2 comes in sizes US 8-14, including half sizes, in seven colorways, one currently on sale at the time of writing. The women’s shoe comes in sizes US 5-11, as well as half sizes, and comes in seven colorways, again, with the Tan colorway currently on sale.
The Tree Flyer 2 also comes with Allbird’s 30-day return policy, meaning that if you wear them and don’t like them, you can get your money back. Shoes that have light wear and tear are donated to charity.
Allbirds Tree Flyer 2 review: Design and fit
Looks-wise, the Tree Flyer 2 looks very similar to its predecessor, although Allbirds has made some tweaks to its running shoe. It’s an eye-catching design, with a geometric design of the outsole, which offers stability underfoot, and the soft bootie upper, designed to wrap around the foot. The upper has been tweaked slightly to give it a bit more structure and extra support in high wear-and-tear areas.
When it comes to the fit, I’d recommend dropping down half a size in these shoes as they come up pretty long in the foot. I usually run in a UK 5, but opted for a UK 4.5 in the Tree Flyer 2, and still had plenty of room in the toebox.
Another thing you’ll notice right out of the box is that the shoe’s carbon footprint is on the back, which reads 7.21kg CO2e — less than the original Tree Flyer, which was 9.92kg CO2e. This stands for kilograms of carbon dioxide equivalent emissions. By keeping a tally of the greenhouse gases, Allbirds are measuring the environmental impact of their products.
The upper of the Tree Flyer 2 is made from eucalyptus fiber rather than the oil-based polyester or nylon that you usually find in running shoes. The sturdy, exposed heel counter is made from recycled materials from the midsole, and the shoe’s laces are made from recycled plastic bottles. Allbirds has also added some Bio TPU overlays (these look plastic, but are sustainable) around the toe and midfoot to add stability, durability, and lateral support.
The upper on the Tree Flyer 2 is definitely an improvement on that used on the Tree Flyer. It fits the foot a lot better, and there’s less excess material. It’s more structured, and during testing, I had no issues getting a locked-down feel in the shoe
The midsole of the Tree Flyer 2 is made from the brand’s SwiftFoam. The ‘high-performance’ midsole is designed to be "big on cushion and energy return, making long runs easier on your body," according to Allbirds. It’s made from castor beans, and is 48% bio-based, reducing the shoe’s carbon footprint.
That said, if you’re used to running in classic EVA midsole foams, you’ll immediately notice that the plant-based foam in the Tree Flyer 2 is a lot firmer underfoot. I wouldn’t say this foam is soft or bouncy — by no means is it an unpleasant ride, but in a world of max-cushioned big, bouncy shoes, this one is definitely on the firmer side.
As with the previous iteration of this shoe, the heel counter and toe box have a flared, geometric style, which is designed to offer stability underfoot.
Again, the outsole of the Tree Flyer 2 remains largely unchanged. It’s made from natural rubber, and there’s a traction pattern designed to give you a good amount of grip when running on concrete, even when it’s wet. The outsole has also been designed to have a good amount of flexibility for a smooth heel-to-toe transition on the run.
Allbirds Tree Flyer 2 review: Running performance
I’ve been running in the Tree Flyer 2 for the past month, and while I have enjoyed this shoe for easy runs and dog walks, as well as HIIT classes that involve some treadmill sessions in the gym, it feels very similar to the first iteration of this shoe. This is by no means a bad thing — it’s a solid, stable everyday running shoe that could easily take you up to around 10K, but it’s not all that versatile, so if you want a shoe that you can wear for tempo sessions and faster miles, this probably isn’t for you.
On the run, the rocker isn’t very dramatic, so you’re not getting that roll forward you get with other everyday running shoes on the market. That said, the large toebox and the firmer midsole make these shoes extremely stable, making them versatile enough to wear in the gym, or on hikes.
That said, I’d argue Allbirds isn’t positioning this running shoe as one to smash PRs in. Instead, it’s designed for runners who want to help make a difference and a sustainable statement with their footwear choices.
Allbirds Tree Flyer 2 review: Verdict
Once again, I absolutely love the message Allbirds is promoting with the Tree Flyer 2 — as a runner who spends time out in the great outdoors, it’s a reminder I, like a lot of others, should be making more sustainable choices.
That said, as a running shoe, this is still best suited to easy miles, up to around 10K. It’s not a performance running shoe, and if you’re looking for a shoe that’ll keep up with all of the sessions in your marathon training schedule, this probably isn’t the one to reach for. Instead, I’d opt for something like the New Balance 1080v13, or the Asics Gel Nimbus 25.