Adizero Adios Pro Evo 2 – 5% more energy return, 10% higher stack, weight.

At Road to records this surely will be worn.

Can't believe how thin the upper looks!

It was #2 and #3 at Boston. But for 500 $ it should have won.

If the best athletes are already signed up by Nike, On or Asics what can Adidas do?

The men's Olympic marathon champ is an Adidas athlete; women's silver also is. Are they elite enough for you?

Well numbers can be thrown around without context so here is some.

"10% higher stack" - well it still has to fall under World Athletics guidelines which are 40mm max in certain positions of the midsole. So even if it's now right on 40mm (whats deemed to be the most "beneficial" height, hence why it's the limit) it means the midsole went from maybe 36mm up to 40mm? Not certain how much an extra 3.6mm of foam is helping you in a practical sense.

"5% more energy return" - so that is referring to the compression and rebound of the foam. But that doesn't mean that your effective energy return is 5% better. There is a difference between the lab result of the foam on a instron machine (which is what they are using) and the energy return you get. If you are putting 2500N of force into the road, in a real world application you aren't simply getting an extra 125N (5% of 2500) back. The basic force, impulse (rate at which you apply the force) etc etc is all different from the lab to reality and across individual athletes.

So numbers are cool - but it's always good to understand in context what they actually mean. Otherwise it's just very good (misleading) marketing.

The Evo 2 was a flop in my opinion. A decent amount of Adidas athletes favored the Evo 1 over it and reviews say it's basically just a slightly bouncier and lighter Pro 4, so nothing revolutionary.

For $500, most will just opt for the lighter Metaspeed Ray at $300.

Not sure why anyone buys adidas running shoes. Their upper is terrible - digs into the heel and ankle.

You want to know exactly why that is? A handful of reasons.

1) The brands (in this case adidas) can talk all they want about lightweight foams etc, but the reality is when you start getting to these substantial stack heights the weight of the product just starts adding up. So to counter this, they need to reduce as much weight in other places. That's why all these products use these crappy thin woven nylon meshes that are saggy and don't hold their shape, and why in areas like the heel they have moved away from quality construction techniques liked stitch and turned collars with good amounts of padding etc etc.

2) It's also a visual/design thing. These are still race products but fat, bloated midsoles don't look intuitively very fast - especially if you had a standard upper on them. So you have to make everything thing and sleek, so forget about your comfort.

3) Biggest thing though? Money. Think about a racing shoe 25 years ago - it was a thin piece of EVA, a rubber outsole and maybe a small injected part in the midfoot for stability (but a lot of the time not even that). Now you have expensive foams that have expensive molds and manufacturing processes (a lot of autoclave, nitrogen gas expansion etc). You have expensive plates or inserts that are all carbon fiber content (not full carbon fiber, just "powder" in the nylon mix) but still expensive, and that's why the shoes are $250-$300. But to keep their margins the brands need to compromise somewhere on the product so similar to the weight issue, the only place they can is on the uppers. So it's cheap meshes, poor construction, no padding - everything on the cheap. Just with adidas alone, if you could ever get your hands on some of the original adizero stuff from around 08 and looked at the uppers you would immediately see the difference.

Hope that helps explain!