If you divide a running shoe into three parts: Upper, Midsole and Outsole, what is eva outsole? If you think of a shoe as a car, then the uppers are the body, the midsole is the suspension, and the outsole is the tire, this shows, in the bottom is the soul of running shoe, also be the core mark that differentiates each big manufacturer, the foundation of business.

The middle base

In the case of this pair of Asics eva sole sport shoes, what’s the eva sole meaning? The white part is the midsole. The function of the midsole is to provide stability, cushioning and springback, absorb the impact of the movement, and provide protection and a more gentle feel for the foot during the movement.

What do you know about the medium base material?

Common foam cushion is EVA products

Ethylene/Vinyl Acetate copolymer, EVA (Ethylene Vinyl Acetate). EVA material has good softness, rubber-like elasticity, and relatively low price has become one of the middle sole materials widely used by major shoe factories.

Generally, the middle sole of entry level running shoes with low price is mostly is make by EVA foam. Such running shoes are usually make directly from EVA materials through cutting and shaping. We believe that many runners have found that a pair of running shoes with EVA medium sole will harden after running a certain distance, this is because after repeated trampling by EVA runners, the air in the foam is force out, then the pressed EVA cannot change back to its original shape, they don’t have the capacity to provide and buffer as much as they used to, so the foot feels hard. If you find shoes like this, it’s time to retire! Just buy, buy, buy!

In order to solve this problem of EVA, EVA was mixed with other polymer materials, and then a variety of different materials were derived. Common names are these:

1. Nike: Cushlon, Phylon, Lunarlon
2. Asics: SPEVA
3. Mizuno: U4iC
4. New Balance: Fresh Foam
5. Brooks: MoGo , BioMoGo
6. Hoka: RMAT, CMEVA
7. Saucony: PowerGrid

Another EVA related material is Phylon, which is a secondary EVA foaming material. In the production process, the raw material is injected into the molding mold, through two high temperature heating, the final firing molding. The density of the material is generally controlled by controlling the temperature during the fabrication process. The higher the temperature, the higher the density and hardness of Phylon. Phylon has a white, wrinkled surface, light texture, good elasticity, and good shock absorption and stability. As a patented technology, most Nike basketball shoes use Phylon midsole.

Some shoes bottom material will be used in PU (polyurethane, polyurethane) and EVA to make the bottom. PU is high density and heavy weight, the advantage is that the durability and buffer capacity is strong. Compared with EVA, PU has no “memory”, it is not easily trample out of shape and detract from buffer performance, the longer life also makes it a common material in the midsole of some high-end shoes.

PU and Phylon can also use together in the same midsole. Generally, soft Phylon is using for the front foot, and stable PU is used for the heel. The gray part of NB1540 is made of PU, while the white part is made of EVA.

Phylite is make y 60% Phylon and 40% rubber, a material used mainly for injection molding. It can using as either a medium base or an outsole. Because it is a mixture of the two materials, Phylite is lighter than rubber, and heavier than Phylon. Running shoes made by this material are characterize through lightness and flexibility, with the disadvantage of poor durability.

We can think of the Free Run+ outsole and the middle sole as one, because they’re both made of Phylite. The black layer above the outsole is BRS 1000 carbon rubber for added stability, as well as the sole.

Lunar is a mixture of EVA and Nitril Rubber (NBR) that is 30% lighter than EVA and Phylon. Nike thinks of ‘Lunar’ as a midsole material, but it doesn’t really make sense. Nike is using ‘Lunar’ more as an aerospace material gimmick.

But unlike traditional midsole materials, they don’t absorb the impact but rather conduct the shock wave, so that distribute the impact is evenly across the foot. Because of its poor durability, Lunar cannot be used alone, so it needs to be in a carrier.

We can think of Lunar as a corpse lying in a coffin, usually made of one of the materials in Phylite or Phylon. Lunarlon if Phylon can use for a carrier; Lunarlite for Phylite, Lunarlite for Phylite, Note that because of its poor durability, Nike doesn’t have any shoes made of Lunarlite, There are a few that have Lunarlite in their name, but they all use Cushlon.

Li-ning Cloud

Li ning’s “cloud” running shoes use the “li ning cloud” midsole, the core of which is “li ning’s unique polymer material formula,” mainly by EVA, rubber and other four different polymer materials polymerization. Li ningyun has different characteristics according to its density. We can roughly understand it as follows: li ningyun with high density has high stable supporting performance of PU, while li ningyun with low density has higher elasticity.

Other materials

The EVA midsole of the most famous is the number of Adidas Boost materials, it USES TPU (plastic rubber, polyurethane elastomer Thermoplastic polyurethanes).

In this part of the midsole, different shoe factories use other materials, for example, Asics’ Gel and Brooks’ DNA, usually put these materials in or on the middle base. The more materials used, the more expensive the shoes will be.

There are also sandals made totally of EVA material.

EVA Clogs and Sandals