A lot of nonsence and overhype about Vaporfly/Next

marshal wrote:

Pebax foam (aka ZoomX foam) has been used in premium racing shoes by leading shoe manufacturers for close to a decade now.

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Carbon plate has been in the track spikes fmuch longer since 90s. To name a few shoes that use pebax foam – Adidas Boost, Reebok Floatride, Under Armour Speedform, Asics Nimbus, Mizuno Wave, Kalenji Kiprun, On Cloudflash etc.

First you have to realise Pebax is both a type of polymers developped by chemical company Arkema (which is funny because INEOS is actually a concurrent company), and a trademark owned by Arkema.

I don't exactly remember the formula, or the way they are protected against concurrents, but I have reached the conclusion than you cannot obtain the exact same from anyone else. Selling points relevant to running are :

- very good elasticity (energy return)

- mechanical behaviour a lot less affected by temperature and humidity changes than other polymers

But second, as far as I know, it is the high density form (as opposed to the low density foam that is zoom X) that as been an industry standard in sport shoes, meaning it was used more for designing plates (instead of using carbon, which is kinda funny), stability posts, etc...

What I do believe is Nike, maybe helped by the application lab of the provider (that's what these guy do typically, just like they helped develop the usage of Pebax in skimo boots like 15-20 years ago) came out with the right density of Pebax foam to have just the right frequency of oscillation needed for the typical elite foot ground time and the typical elite marathoner weight to rebound at the right time, which does 2 things: It still reduces impact just as any very "cushioned" shoe would do and instead of waisting away that energy, it gives it back during push-off. They probably also custom design either the density or the thickness to their superelites custom models to the exact athlete they are destined to. If they have a brain, they should have a non disclosure agreement about whatever exact grade of pebax they are using, and maybe even managed an agreement to make sure they have exclusivity for that exact grade/density.

About the carbon plate, I think it serves 2 purposes:

1° bringing some stability despite the soft feeling foam so the the athlete have a stable plateform to push against

2° maybe it also flexes just ever so slightly. What carbon is great at is returning all of the energy of a flexion in a very snappy way. Just try to ollie a snowboard with standard biax glass fiber, then do the same with a similar model with a layer of carbon fiber if you don't know the difference yet. I still have some trouble getting my mind around the possibility that a carbon plate this thick surrounded by so much soft foam could significantly flex, but after all part of the magic of carbon, is its hability to store a lot of elastic energy in very low amplitude of flexions.

Where you are right is that none of these are either rocket science or ground breaking technology. So it's a question of time only until some other shoe manufacturer could replicate whatever gain exists in the vaporfly against older shoes.

Most will try to use the exact same ingredients, but I would venture into the idea that you could use different receipes to obtain similar results. I really think it's just the idea of taking care of the frequency of oscillation of the system (shoe + runner), just as a racing car engineer would tune the suspension system with that idea in mind.

Wouldn’t that just slow you down?

marshal wrote:

To name a few shoes that use pebax foam – Adidas Boost, Reebok Floatride, Under Armour Speedform, Asics Nimbus, Mizuno Wave, Kalenji Kiprun, On Cloudflash etc.

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When Denis Kimetto ran his WR in Adidas Boost, he did get unfair advantage over any previous runner who ran in shoes without pebax foam. And the same applies now. It's called a technological evolution.

Boost isn't Pebax. Boost is a TPU manufactured by BASF. Pebax is a TPE manufactured by Arkema.

Some of those other shoes you've listed do use Pebax, but not as a foam. From what I understand, Mizuno uses a harder formulation of Pebax for their waveplates (but not the surrounding foam).

This isn't to say Pebax foam is not available to other shoe companies than Nike. Reebok uses it in some (but not all) of their Floatride shoes (and Reebok is owned by Adidas so Adidas is effectively using it in part of their group).

Nike probably has exclusivity on the exact formulation of Pebax they use in ZoomX (as Adidas does with BASF for boost). It definitely appears to be mushier than the Pebax used by other companies and probably only works in that thickness in the Vaporflys becasue the carbon plate adds a load of stiffness. (In the Peg turbo they use a much thinner layer coupled with a layer of React foam).

The *simple* breakthrough Nike made was to combine a load of very lightweight and cushioned foam with a stiff plate.

Previously midsole technology always involved a three way trade off between weight, cushioning and responsiveness. You could pick two of the three to optimise but not all of them. Racing flats are light and responsive but not cushioned. Boost is cushioned and responsive but heavy. Some maximalist shoes like Hoka Cliftons managed to be heavily cushioned and lightweight but are not particularly responsive. Vaporflys are the first shoe to manage all three; as light and responsive as a racing flat but they also provide a load of soft cushioning.

I say it was a *simple* breakthrough - and with hindsight it is conceptually simple but to get there they must have gone through a ridiculous amount of testing of different formulations to get it right. They will get copied and eventually another company will come up with something even better. But for now they have a big lead on everyone else.

OP, I realize that you did a google search for "Pebax Shoes", but all Pebax isn't created equally. The Pebax that has been "used for decades" is processed as a firm shank, not as the springy foam seen in Zoom X. Apples and avocados.

HyperBurst is just as responsive from Skechers if not more

It isn't about the materials used necessarily. It is how the materials are used which Nike has a patent on. Therefore other companies won't be able to fully reproduce the effects of the materials the way Nike has done.

Care to link to the patent you have in mind? WO2016179265A1 seems too restrictive to protect any of the VP versions. It specifically refers to shoes where the spring plate is non destructively removable from the rest of the shoe so that it can be tuned to runner's weight. But maybe you had another one in mind?