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Cap v. Sandwich: Please explain functional difference

post #1 of 16
Thread Starter 
I've never come across a good explanation as to the pros/cons of cap construction v. traditional sandwich construction and would appreciate some clarification & education. I've had a number of skis of either construction and have never really considered either structure to be important to me when choosing a ski.

Also, what is the advantage of "vertical sidewalls"?

Thanks
post #2 of 16
It's become more of a selling point than anything. In the past few years, many companies have been producing their race room skis with a sandwich layup, not because it's better, but because it's easier and cheaper to modify a sandwich ski during testing, a critical feature for a ski company's race R & D department. World cup racers test multiple variations of a ski to find one that it fast, and ease of modification is important.

Race department-inspired skis have hit the market, featuring sandwich construction and, as such, sandwich has become associated with performance. On a consumer level this is more marketing than anything. A top-quality ski can be made in cap, proven by looking at Atomic and Salomon's race stock skis, but sandwich sells skis.

All this being said, a sandwich ski usually suggests that the construction has trickled down from the race lineup, but if the race ski was cap, you wouldn't want to be buying the sandwich ski a company's lineup if you were looking for performance.
post #3 of 16
Traditionally, sandwich was much stiffer in torsion than cap (talking about the eraly Salomon caps). One of the reasons, and probably the main reason, was that many of these ski used lighter foam rather than wood as their main ingredient in order to cut production cost and make the skis cheaper to produce and ship (the Axiendo series, for example, were very light, while still being lively).

The older Dynastar consumer race skis, or the Omecarve, featured a best of both world construction: cap in front and behind the boot, sandwich beneath the boot, in order to have a stiff ski underfoot that would be softer (and easier to initiate/skid) in the tip and tails.

Nowadays, "real" cap construction, the monocoque deal where the skis has an exoskeleton instead of a proper core followed by layers of wood/metal/foam to change its characteristics, is practically gone and we have skis like Atomic and Salomon race stock that can be very stiff, even stiffer than other sandwich race skis. The Atomic venture into cap dowhill race skis last season proved that you could make a comparable, or even a better, race ski, even in the speed events, wich still is 100% sandwich.

PS: There's more to the discussion than just cap and sandwich, there's also torsion box, oversized sidewalls, different materials (Head's liquimetal for example) and technologies (Frequency tuning, Chip, dampening system, Beta lobes, etc.). The difference is much more tradition and personal preference than performance nowadays.
post #4 of 16
Theres a distinct difference in feel when you compare a sandwich vert sidewall ski to a cap ski at least there is to me and I think if you cant feel the difference you either dont care about ski feel or you arent perceptive or you arent skilled enough but to me theres definitely a difference the cap skis tend to hug the terrain less at least in my opinion they do.
post #5 of 16
Thread Starter 
So let me see if I've got this right....

Other factors, such as beta lobes, torsion box, etc. aside - cap construction is ostensibly designed to soften longitudinal flex whereas sandwhich construction increases torsional stiffness?
post #6 of 16
Sandwich construction is considered "core" and cap is not.



I recall when all skis were sandwich construction down to rental models. Now, I think it's funny how a pair or my race skis says "World Cup Sandwich Technology" like it's some kind of bleeding edge construction technique or something.
post #7 of 16
This discussion is way more complicated than simply making generalizations about "cap vs. sandwich."

There are countless exceptions to any generalization one could make. There are many skis out there that look like a "sandwich," but are actually fairly cheesy constructions. Conversely, there are many skis that appear to be "caps," but are actually strong, traditional, constructions that just happened to have the sidewalls covered with a one-piece topheet.

You really need to be specific about which manufacturers & models you are talking about.
post #8 of 16
Quote:
Originally Posted by The Squeaky Wheel View Post
So let me see if I've got this right....

Other factors, such as beta lobes, torsion box, etc. aside - cap construction is ostensibly designed to soften longitudinal flex whereas sandwhich construction increases torsional stiffness?
An extreme oversimplification. More than any other component of ski construction, stiffness is controlled by fiberglass - the amount, how it is weaved, and where in the ski it is located.

In other words, if you were able to make identical, standard core layups - wood core, epoxy, fiberglass, and maybe some titanal - the resulting flex between a "cap" ski and a "sandwich" ski would be difficult for most skiers to feel. It's negligible.

Bottom line, for most manufacturers, cap vs. sandwich vs. beta vs monocoque vs double grip vs whatever is all a dog and pony show. It's what's inside that counts.
post #9 of 16
^^^What He Said^^^

+ The 'general rule of thumb' is that cap construction resists compression. Meaning when you decamber the ski, it stores the energy and returns it at turn completion yielding a snappier, livlier ski.
Sandwich construction allows a slight shearing action between the layers, allowing the ski to track terrain a bit smoother making for excellent edge to snow contact and good grip.

Everything else really needs to be the same in order for either statement to hold any water.
post #10 of 16
Thread Starter 
Great info guys. Thanks.
post #11 of 16
Quote:
Originally Posted by ramshackle View Post
Theres a distinct difference in feel when you compare a sandwich vert sidewall ski to a cap ski at least there is to me and I think if you cant feel the difference you either dont care about ski feel or you arent perceptive or you arent skilled enough but to me theres definitely a difference the cap skis tend to hug the terrain less at least in my opinion they do.
I'm a little curious how you can really say that. AFAIK, there are not two skis on the market, and haven't been in the past several years that are exactly the same, except one is cap and one is sandwich. If you don't have all the other variables controlled, you can't really say what the difference is. As discussed elsewhere in the thread, there are simply too many variables in ski construction to say that "cap construction does this, and sandwich does that."

Having said that, I'd say that you're right in your perceptions that sandwich skis tend to be damper (ie 'hug' the terrain more), but you can't really say that feeling is just because of the sandwich construction when you consider that most sandwich skis on the market are race or race-inspired skis, and hence by definition will be damper than most skis.
post #12 of 16
They way I see it, and correct me if I'm wrong, is that cap and sandwich ski construction, everything else considered equal start at two ends of a flex spectrum. The cap ski being more lively and free flexing, while the sandwich constructed ski being more damp and static. Then the ski manufacturer's add/change things about the ski to change it's flexing properties. The can change the core material of the sandwich construction to make it feel more lively wood->foam or something more dynamic. The cap constructed ski can be made stiffer, or more damp by adding metal or fiberglass or changing the core material. The reality of cap vs. sandwich becomes much more blurred and probably difficult to distinguish.

One other note, I have heard that there are delam problems with sandwich skis, and there are durability issues, but there are durability issues with both construction and it probably rests in the manufacturing rather than the type of construction.
post #13 of 16
Actually there are no 'inherent flex characteristics' of either construction method, the manufacturer has a blank slate to start with, the materials that are chosen will determine flex. The construction method will add a bit of 'spice' to the finished product.
post #14 of 16
Quote:
Originally Posted by Whiteroom View Post
^^^What He Said^^^

+ The 'general rule of thumb' is that cap construction resists compression. Meaning when you decamber the ski, it stores the energy and returns it at turn completion yielding a snappier, livlier ski.
Sandwich construction allows a slight shearing action between the layers, allowing the ski to track terrain a bit smoother making for excellent edge to snow contact and good grip.

Everything else really needs to be the same in order for either statement to hold any water.
Well put.
post #15 of 16
Quote:
Originally Posted by CanuckInstructor View Post
I'm a little curious how you can really say that.
Well I thought it would be obvious but to beat a dead horse heres how I can really say that I just type the words and they come out on the screen in front of you through the magic of computers that can turn keystrokes and electicity into words on a screen and those words even can be transported through telephone lines to a server in some remote location and your computer can access them which is how you came to see what I said.
post #16 of 16
I'm in with ramshackle on this one. There was a "window" of about five years where if you didn't have access to race stock skis, you were on a cap. I switched to Stockli straight sidewall skis after getting pissed at my "civilian race" Volkl and Rossi (a few GS and SL's) .... I got happy again and never looked back.

I have never been on a cap ski that I liked.

Two years ago, you started seeing straight sidewall (Fishers), back on the civilian racks so apparently that "market perception" was shared by others.
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EpicSki › The Barking Bear Forums › On the Snow (Skiing Forums) › Ski Gear Discussion › Cap v. Sandwich: Please explain functional difference