Word to your moms. Here's Silence and I had an actually intelligent conversation about this in another thread and here's what we seemed to agree on:
I don't think that the durability or performance is
inherent in the cap or sidewall construction. Look at it this way, if
you are going to make a ski, you have planned out its design, its
performance, its marketing, everything down to the last detail, even
its lifespan. So, if you are planning on making a ski that is high
performance and super durable, you are looking at an expensive ski
anyway, so why not go ahead and make it sidewall? plus, then you can
use that as a selling point too. Thus, most durable skis ARE going to
be sidewall, but they aren't durable BECAUSE of the sidewall. They were
going to be a high quality ski anyway, and if they had been made with a
cap they would have performed quite the same and been just as durable.
This is why you DO occasionally see a super performing, super durable
cap ski like the Prophet. If the sidewall was inherently more durable,
then you wouldn't see the occasional fall-apart sidewall like the
Liberties from a couple years ago and the first couple generations of
Silence pointed out that when it comes to park skis this is a moot point, it really matters very little. Even if you get a sidewall ski, banking on the fact that proportionally more of them are high quality, you're still going to break it by abusing it on rails and jumps. This is especially true for softer park skis because constant flexing breaks things. Think about what happens when you really bend a flexible ski: you have several sheets of material laying on top of each other, and when you bend the whole complex, the top layers have to bend more sharply than the bottom layers. This pushes those layers up and makes them slide against the bottom layers. Do and experiment: fold a sheet of paper in half a few times. Then, fold it again, when you fold it, the inner layers of the fold are squeezed up and out. This is what is happening to the top layers of your ski when you flex it, they are being pushed away from the bottom layers: DELAM. So, you can pretty much see how park skis are going to delam over time no matter what method you use to hold them together.
Just to back it all up a little more, according to the K2 website 2 years ago, Pep insisted that his pro model be really cheap. Why? Because he knows that a flexible park ski is going to break no matter how you build it, and if you are going to have to buy a new one in a year or so you don't want to pay a lot. So, caps make sense here because they are a cheaper method. But the ski doesn't break BECAUSE of the cap. If the ski was made with sidewalls, it would break just as fast, but it would be more expensive to replace.
So... everyone cool then?