Alright, yeah. This shit has already been kinda cleared up, but as another shop employee, I feel compelled to contribute and just clear everything up based upon my knowledge. It was stated that cap skis have nothing supporting them except for the topsheet contacting the edge, while sidewall skis have a layer of wood or epoxy in between the topsheet and base. I know this is stupid, but are you implying that cap skis basically don't have a core? All skis, cap or sidewall have a core that provides all of the rigidity both lengthwise and torsionally through the ski. The only exception are Salomon skis which have their monocoque construction. This bascially means that the topsheet is strong enough to support the full weight of the skier which is bonded to the edges. This is the only case in which a ski could in theory work without a core. They do use a foam core which acts as a big shock absorber, the topsheet handles the flex and stiffness. Any other company with cap construction relies on the core to handle most of the flex, the construction itself does some, but very little for the flex. The only reasons they are using cap is because it allows them to use a little less material (fiberglass, epoxy, ptex, and/or ABS), it tends to ride softer because of the reduced materials (i.e. making it a perfect design for pricepoint skiers, beginner skiers, and for buttering skis), and it's easier and sometimes cheaper to press depending on what factory they are made in. Sidewall is the most popular, and desired, design today. It still has a core which handles the flex pattern. It usually also has a slight amount of dampening along the edges due to the fact that the edges are supported by a softer, synthetic material (the sidewalls). This makes it perfect for keeping an edge in icy snow at speed, or for rail durability. There is still more torsional rigidity than fully capped skis because of added material like fiberglass to the core. Sidewall skis can also be repaired to an extent due to the fact that the sidewalls can be removed and reglued after that repair is made. This is difficult for capped skis due to the fact that the topsheet is bonded into the ski and is one big part. This makes capped skis more prone to delams, and the severity of a delam is greater in a capped ski since it can be harder to repair. Sidewall skis have a sidewall protecting the topsheet from getting banged off by edges or obstacles. And if they do delam, everything can easily be glued back into place. Main point- cap skis are softer and a little more prone to damage, but they are cheaper and provide some "edge feel." Sidewall skis are stiffer, stronger, easier to repair, but usually more expensive. These are the factors companies take into consideration when designing a ski. That is why they use a certain design, or a mix of both, for certain different models of skis. This is what happens when you have a 2-hour break in college with nothing to do. Hopefully this can clear some stuff up.
