The Allbirds Tree Flyer is one of the brand’s latest attempts at producing a shoe for performance running. The Tree Flyer is said to be “lightweight, super springy, and wildly comfortable, this distance running shoe makes your extra efforts feel effortless.”. This is delivered through several innovations in the Tree Flyer. For example, the geometric midsole design for stability or the new midsole material, the SwiftFoam. The SwiftFoam is 48% bio-based and seeks to provide cushion and comfort during the runs. The Tree Flyer had also gone through extensive testing and development with over 100 runners in various conditions and climates.

Product Specifications

  • Price: US$160
  • Size: US 11
  • Weight: 311 grams (10.97 oz)
  • Midsole Type: SwiftFoam
  • Stack Height: 23.5 mm to 32 mm (8.5 mm drop)
  • Insole: EVA based insole (3mm thickness)
  • Forefoot Width: 11.5 cm
  • Midfoot Width: 7.0 cm
  • Heel Width: 8.7 cm

Runner’s Profile

Prior to the review, it is important to establish my runner profile to better gauge my opinions on the shoes. For example, a lighter runner will experience differently the effects of midsole compared to a heavier runner. I am on the heavy side for a runner (75kg – 80kg) range and stands at 1.75m tall. My average weekly mileage ranges from 25km to 35km. I am a mid-foot/fore-foot strike with a neutral foot. I am normally a US size 11, with 2E foot width, although it varies depending on brands.


These five main key pointers are based off my first run(s) in the Allbirds Tree Flyer. These key pointers can remain the same as I continue using the footwear or it could change as I go on. In the final review, after 100KM, additional pointers could be added to provide an accurate review of the footwear.

Pointer 1 – Mid-of-the-Pack Weight for Today’s Market

The Tree Flyer isn’t the heaviest running shoes in the market. My key comparisons for the Tree Flyer are the Puma Velocity Nitro 2 and Allbirds own Tree Dasher 2. The Tree Flyer is lighter by 17 grams than my Tree Dasher 2. But we must take note that the Tree Flyer has a taller stack height as well as a more build up outsole. To achieve a lighter weight despite of these does showcase Allbirds capability to innovate and push the boundaries.

In comparison to the Puma Velocity Nitro 2, a very popular model, the Tree Flyer is only about 5 ~ 6 grams heavier. For training and clocking the miles, I think if the weight is close to the Velocity Nitro 2, it is acceptable for me. There are no doubt lighter models such as Novablast 3 and Pegasus 39 but for where Allbirds started off from, it is good progress.  

Pointer 2 – High Durability is Expected Overall.

The overall construction from the upper down to the outsole is expected to provide high durability. This is quite early to say but looking at the outsole material and pattern, I do expect the outsole to last longer than the midsole will. The upper is a single layer eucalyptus fiber coupled with some inner lining which locks the foot in.

Pointer 3 – Firm and Unforgiving SwiftFoam

While Allbirds said that the SwiftFoam is the new high-performance midsole which provides cushion and energy return, I have yet to experience it thus far. The first few runs I had in the Tree Flyer left my legs more tired than I was expected given the distance and effort. The SwiftFoam is very firm and felt blocky during my runs. There is certainly one thing I hope for the SwiftFoam, please soften up after more runs. There are good and bad to a firm foam which breaks in after more runs. One good point is that the durability is expected to be longer, but the bad point is it takes time to break in.

Here is a disclaimer and worthy point to take note. The outsole of the Tree Flyer is very firm, much firmer than the other outsoles which I have seen thus far. This could be a factor causing the very firm underfoot experience for Tree Flyer. This is my hypothesis from my first impression, I will let you all know if it is true or not in my final review.

Pointer 4 – Tough & Durable Outsole expected with FSC-certified Natural Rubber.

The outsole of the Tree Flyer is made from FSC-certified natural rubber ensuring the product maintains its sustainability approach. A tough outsole of the Tree Flyer is expected to provide a good amount of durability over its usage. Additionally, the patterns and size of the lugs for the outsole could provide good traction even over light trails.

Pointer 5 – An Expensive Pair of Running Shoes

For all runners, being green is certainly one of the factors when buying a new pair of running shoes. But performance and cost are other factors that heavily influence the buying decision. The perception of expensive or not is highly dependent on the perceived performance that a pair of running shoes provides. For the Tree Flyer, it is an expensive pair of running shoes in today’s marketplace for the performance it provides. At US$ 160, there are many better performing running shoes (e.g., Triumph 20 or Tempus at US$160, Pegasus 40 at US$130) that serves the runner’s need.

Concluding Remarks

The Allbirds Tree Flyer is an amazing feat to accomplish given the constraints and challenges Allbirds face. It is the brand’s first big attempt at tackling the performance running market. In my opinion, Allbirds had some success with their Tree Dasher 2 and the Tree Flyer could set to fly. However, at the current moment, I think the Tree Flyer fell short overall. This primarily comes from the performance of the SwiftFoam which dragged down the appeal of the Tree Flyer as a serious contender in the performance running market.

There are hopes nonetheless for the Tree Flyer and it is simple, it starts with the midsole. If the SwiftFoam starts breaking in and soften up after more runs in the Tree Flyer, this would greatly increase its appeal. Else, I would suggest that Allbirds tackle this midsole problem and improve on the SwiftFoam as it is a big hurdle to its success.

Personally, I hope that the Tree Flyer will soften up and that it will be the next generation running shoes with sustainability in mind. For it is precisely these challenges which can make for the next level of innovations.

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