Huarache International: Phylon midsole
Skylon TC: Phylon midsole
Air max: Poly-midsole
The first two pair of shoes, the Skylons (91) and the Huarache International (93), are perfectly wearable.. i already have worn both without a problem… the air maxes (92) and the Pegasus (90) will crack, without a doubt…So, i wondered why do some of these runners crack, while others are perfectly wearable (like my huaraches, skylons, …)
I am sure the answer is the type of midsole used… Nike used mainly two types of midsoles on their runners…
the first type is called Phylon, and is the material used on the skylons, huarache internationals, huarache lights, huarache’s LE, air icarus, air analogs, etcetera….
the second type is Polyurethane and is the material used on all the air maxes, but also the Pegasus, the tailwinds, air classic BWs,….
well, just out of experience, shoes that belong to the phylon group, i have never seen crack… (it could happen, but i atleast haven’t seen it yet), and secondly, they almost never show midsole discoloration (again, can happen, but haven’t seen it yet)
shoes of the second group, the polyurethanemidsoled shoes, they are almost guaranteed to crack, and will turn yellow after a while….
conclusion: don’t worry when you buy some original base’s or huaraches, or skylons probably they are good to wear
Only problem is that it is sometimes difficult to say which material is used on which shoes. The nike catalogs could be a help, because they always states the materials used on the shoes. but let’s say that midsole discoloration mostly isn’t a good sign.