Leo Chang and Kevin Durant would make a perfect sitcom duo, simply because the differences between them as they stand side by side are so striking. Chang is short, with jet black hair that falls well below his shoulders. His face exudes a consistent look of mild bewilderment, as if he’s not entirely sure how he came to be the lead designer for Nike Basketball. Durant is enormous and slight at the same time, a human stick bug walking the basketball court. His hair is short, and his gaze, though innocent enough on the surface, has intensity and rage behind it, as if he’s ready to go and drop 30 on you at any moment.

Fortunately, Chang and Durant work on shoes together, not television. Chang’s vision, with input and wear-testing from Durant, has shaped the Oklahoma City Thunder star’s signature line, which began in 2009 with the release of the KD1. They’re up to number nine now, and it’s the most radical KD shoe since version IV debuted a strap across the upper.

Incorporating Flyknit technology for the first time in a Durant sneaker, and adding Nike Zoom Air pods on the sole, make the KD 9 starkly different from its predecessors.

We caught up with Chang at the unveiling of the KD 9 in New York City to chat about his favorite part of the shoe, the challenge of creating a new KD model every season, and whether Durant has ever hated something he’s designed.

STACK: You mentioned that Kevin Durant had wanted Flyknit in his shoe ever since it debuted in the Kobe 9. How did you eventually get there?

Chang: I think he and I have a good relationship where he’ll throw ideas at me and I’ll throw ideas at him, and it’s good cooperation. A lot of times he’ll say stuff to me, but he may not know what’s behind the curtains at Nike, the innovations that happen. So I’ll bring that to the table to see if it’s right for him. I’ll filter in and say, “I think that would be amazing for your game.” So that’s the process.

The Flyknit thing, obviously Kobe started it on his shoe, and it was great for him to pioneer that in basketball. Kevin saw that and loved it too. For us, I just wanted to make sure that when we do it, it’s right for him.

What’s your favorite part of the KD 9?

I think I like the overall gesture of the shoe. There’s a rawness to it that I like about it; with the Knit, it feels like there’s such a dimensionality of texture to it that it felt kind of natural and raw. But then mixing it with something technical, like the Zoom bottom. I feel like there’s something unique that came out of that.

Is it hard for you to come up with a new model for Durant every season, especially if he really liked the previous one?

Luckily for [the players], they go through a whole season of wearing a shoe, and I think they’re ready for another one. But, when talking about the 9, we were having discussions about it and I asked him, “What’s your perfect shoe, what does that feel like to you?” Not even a shoe you’ve tried before. He still said the KD 8 at the time.  He was like, “The KD8 to date is still the perfect shoe.” When he first tried it on, it was before his injury happened, he had such a good memory in his head of what that felt like. That’s the one that you’ve got to beat. So that was a good challenge, to try and raise the bar on that one.

Have you found a comfort zone with KD, where you two are very much on the same page in terms of what he wants from his shoes?

Early on he was definitely less vocal. More and more over the years I’ve encouraged him to be more vocal. I want [him] to hate stuff too, you know? It’s OK. So he’s been great about that. When we started on the [KD 5] is when he first told me, like he liked it at first, but I think he was just being nice to me. He was like, “No I think we need to go back to the lab on that one.” It’s good for me to know the goods and the bads, so you have some boundaries and guardrails around that.

What did he want changed?

He wanted an Air Max bag in the heel and he wanted it to be more of a mid-cut. The design I showed him wasn’t any of that [laughing].

Does having Nike shoes for other athletes, like LeBron and Kobe, help in the design process each year?

Oh, of course. All these guys look at each other’s stuff. It’s good. I think it’s nice that they can have comparisons and try it on. And they know what works for them and what doesn’t.