Salomon has had a longstanding commitment to socially responsible manufacturing practices, and this spring they are debuting a flagship running shoe that exemplifies this concept. The Index.01 is designed as a high performance road running shoe that is completely recyclable: it is made entirely of repurposed materials and is intended to be completely disassembled and recycled after its lifespan, with the raw materials incorporated into other Salomon products.
The Index.01 is the culmination of three years of research and development at Salomon headquarters in Annecy, France, where their design center looks to minimize material waste and lessen the environmental impact of footwear through circular life cycle principles. However, it wasn’t enough just to produce a recyclable running shoe. The team made every effort to maintain the level of performance that Salomon users expect, particularly because the shoe comes with a hefty price tag, which is often the case with early adoption concept products.
Uppers of the Index.01 consist of a very thin, recycled polyester mesh with large ventilation holes and a small window of fully translucent mesh on the lateral midfoot. There is a bare minimum of cushioning on the tongue and around the heel collar, and a thin TPU protective bumper around the perimeter. It has a super airy and lightweight feel that rides like a sock and ventilates extremely well, with a last that will accommodate most foot sizes. The upper is secured to the midsole with a water-based glue and recyclable polyester thread to minimize material contamination during assembly. Because it is a unisex model, sizing can be a bit tricky, particularly for women: you have to use the guide on the Salomon website which involves tracing your foot and then measuring a line through it to find the proper size. As a general rule, women’s sizes track one full size below men’s, but be sure to double check.
Critical to the success of this shoe is the midsole material, and the Index.01 features a new Infiniride compound made of 100% TPU infused with nitrogen for maximal energy return. The goal for this compound is to balance comfort and durability, while providing a ride quality comparable to other Salomon road shoes. Development of the final compound included real-world testing over hundreds of miles of running, and also lab testing to replicate maximal impacts and stresses. In our testing, the resulting compound feels significantly firmer than most road shoes we’ve used, with strong energy return but very little cushiony feel.
Asymmetric midsole geometry in heel
Another key element of the midsole is its unusual geometry, particularly in the rearfoot where the TPU platform flares outward and has an asymmetric footprint on the medial and lateral sides of the heel. It seems that the intent here is to provide very subtle guidance at foot strike to initiate impact with the lateral side of the heel, then roll naturally through the medial forefoot during the stance phase. Forward propulsion is accentuated by a steep, reverse camber design that functionally rolls your foot toward push-off. This works as advertised, and provides a very smooth transfer of energy after foot impact. With a relatively steep 9mm drop in the midsole platform, the Index.01 is more suitable for heel strikers than midfoot landers.
Rubberized TPU in heel and forefoot; regular TPU in midfoot
Speaking of heel striking, this area of the outsole is reinforced with a thin layer of small rubberized TPU cleats, as is the forefoot. The compound provides better traction in wet and dry conditions than it might appear, but this is also the area where we have seen the most wear. Many of the TPU cleats in the heel wore down to their base within about 50 miles of testing on our pair, and we anticipate this will be the case for most users due to the heel-toe geometry that promotes heel striking. Once the cleats are worn down, the grip on asphalt is still strong, but gravel roads and wet surfaces become a bit uneasy. Salomon classifies the Index.01 as a “2–3 runs per week” shoe, so it’s not intended for higher mileage, although the company’s field testing has validated the outsole durability beyond 200 miles.
Closeup of rubberized TPU cleats in heel (right) and regular TPU in midfoot
Whenever you’re finished with the Index.01, you can contribute to Salomon’s environmental efforts. The company has established regional collection networks across Europe, Asia and North America, and customers can print a free shipping label at www.salomon.com that will direct the shoes to the nearest collection center. Once collected, the shoes are completely disassembled, with the uppers used for new fabric creation, and the TPU unit will be ground down into tiny particles that can then be used for a variety of purposes. Salomon says that chief among these will be construction of TPU shells for alpine ski boots.
As a proof of concept, the Index.01 is a remarkable shoe that hopefully signals a new era in shoe manufacturing and repurposing. As a performance shoe, it’s good but not outstanding and definitely not the best Salomon ride you can get for $200. It would be cool to see some sort of discount or rebate program built in to repeated purchases of the Index.01 so you’re incentivized to stay within the circular life cycle, and the initial investment becomes more justifiable over the long term. This economic model is similar to other disruptive green technologies that ultimately gain traction, and the Index.01 deserves to be considered in the same category.
Features and Specs:
- Weight (unisex): 10.0oz – size 9
- Stack Heights (heel/toe): 28.5mm/19.5mm
- Heel-toe Drop: 9mm
- Color: Any one you want, as long as it’s white
- Uppers: lightweight recycled polyester mesh
- Midsole: Infiniride nitrogen-infused TPU foam
- Outsole: Rubberized TPU
- MSRP: $200
The Salomon Index.01 shoe is now available at www.salomon.com.