Design Decisions:
Exploring the Minimus HI-REZ Upper

If the heart of Minimus HI-REZ is its revolutionary outsole— that individually-podded piece of fabric helping maximize underfoot sensation—then its upper is the brains: a delicately constructed testament to precision, strategy and balance between competing, and often conflicting ideologies. As New Balance Lead Designer Chris Wawrousek puts it, designing it was an exercise in determining "how little we could get away with." We sat down with Chris as he guided us through the decisions that were made in constructing HI-REZ's upper.

Building the upper was a constant battle of opposing design decisions: materials versus protection; stretch versus structure; breathability versus support. The New Balance design team had to be strategic in balancing minimalism with practicality.

Chris: Because of the complications in stitching the bottom to the upper—the operator has to actually be quite skilled to sew those two pieces together—it makes sense to have the upper be very streamlined and not have too many materials.

The uniqueness of the HI-REZ outsole begged for an upper to match it, which forced them to think about the kind of foot experience they wanted people to have. Early concepts revolved around a "no lace" version that was more about stretch and hugging the foot. Ultimately they decided laces were the way to go.

Chris: It started as a stretch-fit upper but there's a certain comfort level with laces. They provide a remarkable amount of adjustability that's hard to replicate any other way.

As a base material, the designers chose a flexible, light synthetic performance mesh, which allowed them to eliminate irritation points inside and keep support elements on the outside.

Chris: The nice thing about Fantom Fit is that it allowed us to use a very clean interior construction and provide that support through surface treatment.

In deciding where to put the seams, the designers identified certain areas that would allow them to shape the shoe correctly and also minimize the number of seams needed throughout.

Chris: It's really a matter of finding that perfect, "If we cut it right here, is that going to give us the most 'bang for the seam', so to speak?"

As was the case with the outsole, designing the upper was a trial and error process that took the team through more than a few iterations before they felt they were on the right track.

Chris: This prototype is probably representative of the breakthrough point, where we started to feel like, "Alright, we've really got something here." There's always these ups and downs in the design process, and this one was an affirmation that we were getting close.

A close inspection of the HI-REZ upper reveals a thin rubber layer used to reinforce the side seams, as well as a rubber tape overlay throughout that preserves the integrity of the mesh.

Chris: That's another reason why we actually chose the rubber tape overlay, because should someone actually start to roll out and run on the side, there's a buffer of protection that's more than if it was just fabric and stitch.

Constructing the upper in this way let the designers target specific zones around the shoe to have a certain amount of stretch in one area and a very specific amount of support in another.

Chris: Rather than it be either "support" or "no support", it's sort of blending those support elements in a unique way to provide what you'd consider to be a more ideal upper configuration.

For Chris, the most interesting part of this project was gauging people's reactions when they first try on the shoe. Due to the outsole's unique design, the upper moves in a way that a normal shoe wouldn't—giving people a totally unique sensation that they might not otherwise expect from a running shoe.

Chris: In a normal shoe, the upper is fixed in one position, and the bottom moves [in one linear position]. Whereas for HI-REZ, the bottom is totally loose, so the upper moves along with the shoe, and parts of it bend and flex toward you.

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