I have read that shoes - more specifically the foam in shoes - "expire".
Is this true?
I have read that shoes - more specifically the foam in shoes - "expire".
Is this true?
They don't 'expire' like food does.
But if you use them enough, the materials (like the foam) will compress. And eventually the cushioning is toast because it has compressed to a point where it no longer cushions.
You can also wear down the outer sole so that it loses tread or starts peeling off.
You can wear through the mesh upper and get holes which erode the snug fit keeping your foot on the footbed.
So, I supposed they "expire" after many miles of use. I think the rule of thumb is 300-500 miles, or 200-400 for a racing flat. Many people begin to feel aches and pains when the shoe starts to wear out. I know I've used my shoes too much when the knees/hips/back/shins start hurting.
Thanks.
Now I know this might sound crazy, but I've heard that the foam itself can release air or something as it sits around for years, so that if you tried on shoes that are 5 years old but unused that the cushioning would't be as good.
Is this total nonsense?
I knew a guy who ran in college in the early '70s, and when we had a college alumni reunion fun run, he ran in an old pair of trainers he had from college. halfway through the run the midsole tore apart and the foam was "rotting" apart on the inside.
I put "rotting" in quotes because it wasn't really rot, it was probably just deterioration from decades of storage and maybe exposure to humidity. I do not know if modern foams deteriorate in the same way. You can bet that the shelf life of a shoe is AT LEAST several years - think about how long it takes for the shoe's midsole to make it from the factory floor to your feet: it needs to be manufactured, formed, incorporated into a shoe, shipped to the other side of the world, probably via container ship, unloaded, sent to a warehouse, distributed to running stores via truck, and then stored at the shoe store until you finally show up and buy it. That whole process could easily be over a year, and if shoes started going bad, you'd hear about it all the time (and designers would fix it).
All conventional running shoes manufacturers says so (and in their wake all the running magazines say it too), but as of yet I have never seen any data proving it's true or showing how long this process takes.
Let's just conclude that it's quite convenient for the shoe brands…
You have to buy new shoes after a few hundred miles 'because the dampening material is worn out after that'.
You have to buy new shoes every year 'because the dampening material loses it's quality with age'.
You have to use several pairs of shoes 'becuase the dampening material needs some time to recover before it can be used again'.
Many years ago Nike's Air shoes were supposed to battle all that, because the air cushions didn't suffer from the same thing. But hey, Nike somehow stopped using Air in most of their shoes. Wonder why that is…
I stopped using conventional running shoes many years ago and never looked back. I simply run my minimalistic ('barefoot') shoes until they either fall apart or until my foot sticks through the rubber sole. But hey, keep buying those shortlived super shoes everybody! :-)
I have a 5-7 years old Mizuno with ~150M on it. I keep it in my parents house so that I can do a run when I visit them. I noticed that the cushioning is very strange, it definitively wasnt so a couple of years ago. Moreover, the shoe still looks nice but the running feel is not what I would expect. It is difficult to say.
asdfasdfdsf wrote:
I do not know if modern foams deteriorate in the same way. You can bet that the shelf life of a shoe is AT LEAST several years - think about how long it takes for the shoe's midsole to make it from the factory floor to your feet: it needs to be manufactured, formed, incorporated into a shoe, shipped to the other side of the world, probably via container ship, unloaded, sent to a warehouse, distributed to running stores via truck, and then stored at the shoe store until you finally show up and buy it. That whole process could easily be over a year, and if shoes started going bad, you'd hear about it all the time (and designers would fix it).
I've wondered about this when looking at shoes that have obviously sat in a shop for a long time (old models).
Chemist here.
Running shoes do expire.
I doubt any expire in less than 5 years. The problem is telling when they were actually made.
lknjs7wq4 wrote:
The problem is telling when they were actually made.
It seems like quality running shoes go through model updates every year or two so one should have a well constrained window (a year or two) of when a particular shoe was the current model. Manufacturers and distributors don't like to sit on excess inventory any longer than they have to for obvious economic reasons, so the lag between manufacture and first availability on market is likely no more than a few months.
Anecdotally, when I've found a shoe I like, I've kept a couple "new" pairs in my personal inventory, often buying up stock of a previous generation when a distributor is clearing old stock. Thus I've run on shoes that are probably 3-4 years from date of manufacture and have never experienced noticeable degradation. I have noticed with court shoe that the soles get hard and lose grip, but those are more than a few years old. In my usage running shoes get worn out long before they age out.
I used to keep a pair of racing flats in my car trunk in case I needed to get somewhere after an auto incident. When it was time to retire the car, I removed the flats and wore them for a track workout. They felt horrible--stiff, dead, like running in Chuck Taylors. This was after maybe 5 years in the car.
I would guess the deterioration would be even more noticeable in a more cushioned training shoe.
Midsoles do deteriorate over time as they are mostly foam (EVA) based. It can vary depending on many factors such as heat, humidity, air flow where they are stored, how frequently they're used, overall age, ect. It won't happen in a few years, and rarely is the shoe completely useless, but if you take a brand new shoe and put it in the closet for 5 years, you probably won't get the normal 300-500 miles out of it. There have been extreme cases, mostly in people who collect sneakers like Jordans where you pull it out of the closet and the midsole has completely crumbled (see link) http://sneakertalk.yuku.com/topic/328954#.VVyWtPlViko. Also the glue can harden and go bad causing the outsole, midsole, or upper to separate. If you just use your shoes normally this will probably not happen, but if you buy 20 pairs of your favorite model to stock up, unless you're doing 100 mile weeks, they will probably not last.