Why Are Skis So Heavy? Ski Weight Matters
At the end of a long day when you swing your skis up onto your shoulder, you are reminded of just how heavy they are. Why do they need to be so heavy? Surely, they could be made from lighter materials.
Today, skis weigh significantly less than they ever have, but they still average 10-15 pounds a pair. They have to be heavy enough to maintain contact with the snow surface and sustain repeated flexing and bending. Lighter skis are easier to maneuver but tend to reduce performance.
The construction of skis is always a compromise of many factors. In its simplest form, the ski needs to have strength, flexibility, and durability to offer the best performance.
The average pair of skis weigh about 10-15 pounds (4.5-6.8 kg). The materials used in manufacturing vary enormously so it is difficult to be categoric about weight. However, you can assume that the wider and longer the skis are the heavier they will be.
Choosing to ski with a heavy or light ski comes down purely to choice. Some skiers prefer heavy skis, so they feel more connected and confident on the snow or more able to easily ride over chopped-up snow. On the downside, heavy skis are less maneuverable, while lighter skis are very easy to maneuver but the lower weight results in loss of performance, especially when skiing across difficult terrain.
Ski construction has come on in leaps and bounds since the early days of carved, solid hickory skis. Manufacturers use complex composite layers, which are built up to give optimum strength, flexibility, and durability, while not becoming too heavy in the process.
Construction is not an exact science and so each manufacturer chooses their own materials and construction techniques. By looking at the different elements that make up the ski you can get an insight into whether they are heavy or light.
Nearly all skis have a laminated wood core at the center, and it is this core, which gives the ski its longitudinal rigidity and general characteristics. All other parts of the composites are attached to this central core.
Wooden ski cores are generally made from laminated layers of hardwood such as beech, birch, ash, fir, maple, spruce, and poplar. Wood is still popular as a core material as it has the right springiness, durability, and the ability to damp vibrations.
Often other materials are added to the core section to achieve extra benefits depending on the style of skiing being manufactured. The wooden part of the core can vary in length but often the wood will run the entire length. These include:
Aluminum - is light and strong but has poor damping properties
Fiberglass - is strong, light, and cheap
Carbon - is light and strong with good springiness but very expensive
Kevlar - is very strong, light and performs well under tension
Titanium - is very light and strong, good at damping but expensive
Foam - is used less often but can be useful to reduce weight
The core section of the ski is the most complicated with different materials arranged in different patterns to achieve different properties in the ski. It’s not unusual to use different woods, along with other materials such as foam and carbon to create the correct characteristics, such as strength, flexibility, and overall weight.
The composite layers are the next addition going above and below the wooden core. These layers act to protect the core and also contribute to the strength and flexibility of the ski. Often fiberglass is the first choice, its strength, springiness, flexibility, and cheapness make it an all-around winner.
In a similar manner to the wooden core, the composite layers are often made up of a combination of materials to create the characteristics of the overall ski. Normally epoxy resin is used as the adhesive to hold all the different composite layers together.
Once the wooden core and composite layers are assembled the sidewall is attached. The sidewall is an area along the edge of the ski but above the metal edge. There are different sidewall constructions, which play a part in the ski’s performance.
The top sheet on the ski is the uppermost layer, which is visible. It acts as a barrier to stop water and dirt from gaining access to the laminate layers and also supports the brand graphics for the make of the ski. The top sheet is only a thin layer, which is often made of nylon, fiberglass, and composites.
Ski base technology constantly evolves but currently, ultra-high-molecular-weight polyethylene (UHMW-PE) is the most popular choice. This layer is very thin, only about 2mm thick.
Some polyethylene surfaces are treated to create tiny holes in the surface into which wax can absorb making for a better glide. Similarly, carbon can also be added to the polyethylene to reduce static electricity build-up, which is generated by the friction between the ski and snow surface.
The ski edge is a vital part of the ski that takes a considerable pounding. They ensure that the skier can corner and maneuver effectively. For durability, they are made of steel or stainless steel and are housed between the lower composite layer and the base.
There are two types of edge, a full wrap, which is made of one continuous piece of steel which runs around the entire circumference of the ski. In the second type, the partial wrap, the steel edge is only applied along the side of the ski where the sidecut is. There are advantages and disadvantages to both, the partial wrap is lighter, and the full wrap is much more durable.
Why Do Slalom Racers Use Heavy Skis?
When racing competitively slalom racers subject their skis to enormous forces as they repeatedly turn down the course. Their skis are specially made with two metal sheets as part of the composite construction. It’s this extra reinforcement that helps to maintain the torsional rigidity of the ski, which helps the racer to maintain good control. The skis are less flexible and have a denser core providing the necessary stability at speed.