Ultreya and nmblFoam®

Direct Injection and Dual Density make a difference for runners and the environment

In producing the nbmlFoam® sole for the Ultreya, Joe Nimble was the first running shoe manufacturer in the world to bring a revolutionary process to production maturity: we produce our energy return soles using a combination of Direct Injection and Dual Density.

Direct Injection: Injection instead of gluing

Direct Injection means that the soles are no longer glued, as has been common in the industry up to now, but injected directly into a mold. This has advantages for runners and for the environment:

  • we save water and energy because the sole no longer has to be heated or melted
  • we do not use adhesives, which can have a negative impact on the cushioning in the shoe due to an additional intermediate layer or the stiffening of bonded materials
  • we improve the connection between the sole and the upper because the midsole is firmly bonded to the upper during production

Dual Density: With the right density in the right place for a stable running experience

An absolute novelty in the industry is also to combine Direct Injection with Dual Density. This enables us to inject the sole automatically in two densities:

  • the frame of the sole for a stable landing phase
  • the inside of the sole guarantees soft cushioning

As a result, runners benefit from greater stability than with classic midsole foams, in which the running experience can often feel spongy.

PU instead of EVA: Better compression set and longer durability

We chose PU as the basis for our nmblFoam®. It is true that the so-called “supercritical” EVA-based foams offer the highest recovery force. However, they often have the disadvantage that the material fatigues more with each load.

This triggers a vicious circle: When a runner overpronates due to their body or foot structure, they put more stress on the sole at that point and the foam fatigues faster. And this fatigue promotes the weak point in the runner’s body structure and can lead to negative movement patterns.

For this reason, we looked for alternatives to EVA-based foams for our nmblFoam® and chose PU. The advantages:

  • the continuously dense foam is characterized by a deep and, above all, permanently consistent energy return
  • ten times higher compression set (ability to return to its original shape) than conventional EVA foams
  • longer durability
  • hydrolysis free (advantage in hotter or more humid climates)

Automation reduces carbon footprint

Highly automated manufacturing also allows Joe Nimble to profitably move production of the Ultreya back to Europe and Germany. This makes us less dependent on supply chains. And it brings us closer to the goal we aim for with every new development step: to produce our shoes in a CO2-neutral way for the foreseeable future.