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  • Writer's picturePaul Lorenz


The most commonly asked question of trainers is “what skis should I buy to use for training and/or instructor exams”? With so many brands, radiuses, widths and lengths to choose from, it is a tricky decision, whether you are an advanced skier, first time instructor or a seasoned ski professional.

Identifying the primary use of the skis is the first step. Once this is determined, there are 4 main characteristics to consider that will affect the ski's ability to perform its objective: ski radius, width, length and stiffness. In this article I will shed some light on these areas and give you some information to help make the decision when the time comes.

Ski Radius Firstly let’s tackle the radius. Unfortunately there is no radius that is perfect for everything. A shorter slalom radius (12-13m) will always be better suited to a shorter radius turn, and a longer radius (19 - 30m) to a medium/longer radius turn. A common thought is that slalom skis (SL skis) are the ideal ski as most instructors, trainers and examiners are skiing around on them. A shorter radius ski does show very dynamic skiing and can be a useful training ski for those learning to pure carve. A lot of people say that a skier can become lazy on this type of ski by becoming heavily reliant on the short radius sidecut to turn. If these skis are skied properly, I find them more of a workout than any other radius ski as they can create a lot of pressure very quickly.

Shorter radius skis have certain drawbacks though. When demonstrating slower moving tasks (for instructors), it is very easy to get caught on the edge and “rail”, or “carve” what should be a “steered” performance turn. Not adhering to the performance guidelines in an instructor exam is an automatic fail. At the high end of skiing, a shorter radius ski makes it very easy to park and ride (or “rail”) longer turns rather than bending or “working” the ski. This short radius can also be a hinderance in the bumps, creating additional pressure on top of the forces already created by the moguls. With skill and a lot of training, slalom skis can perform very well for most technical tasks (with the exception of longer radius turns) and also for instructor exams but are not an ideal ski for overall versatility.

The slalom skis’ longer radius counterpart, Giant Slalom (GS) skis, are great for purely carving longer radius turns at speed on the groomed trails. This radius is a little more versatile for skiing the moguls and does not have the SL issues for instructors performing low end demos. However, this radius requires much stronger leg turning and skill blending to produce tasks that are not purely carved (i.e. for steep skiing, short turning etc.) These skis can be good to demonstrate these tasks (for instructor exam purposes) if you are confident, but like the slalom skis, are not ideal for exams.

While both of the above skis are perfect for a specific performance and turn type, an “in between” radius ski (14-19m) is a good compromise for high end recreational skiers and also for instructors sitting exams. It has enough shape to perform short turns but not so much that it inhibits medium to long turns. It allows for reasonably dynamic skiing across the board and also allows the demonstration of the appropriate skills for instructors showing slower moving tasks. This “all mountain/skierX” radius is a good compromise for those teaching skiing or participating in instructor exams, as versatility is the key.

For the higher level recreational skiers, this in between ski will allow you to ski the entire resort. Remember though that this radius is a compromise and will never compete with and SL radius for shorts or GS radius for longs. If you are lucky enough to acquire a quiver of skis, then the feeling of laying freshly tuned GS skis over on perfect corduroy is extremely exhilarating, as is the kick created from short turning a pair of SL skis down a steep face.

Racers will of course use the specific radius ski to suit the event they are racing, as this will help minimise the loss of speed. There are also strict regulations as to the radius of skis used for all FIS ski racing events. Some skiers competing in technical skiing competitions will in fact carry 2 or 3 sets of skis for better results in each specific task (e.g. SL for short turning tasks and GS for longs).

For those who are interested in purchasing a powder ski and are wondering which radius to select, similar guidelines apply. That said, these days most powder skiers are going for speed and wider turn shapes, meaning that a slightly longer radius ski (e.g. 18-27m) would be the most beneficial.

Width Trends in ski widths these days have changed drastically from those of the skinny straight skis of the 80's/90's. People are tending to ski a lot more off piste, back, and side country, and as such everything has gone wide! When looking at the width of skis there are 3 measurements that are important: the width of the ski tip, the width under foot, and the width of the tail. The relationships between these 3 widths dictate the shape or radius of the ski also. However, most of the time when someone refers to a single measurement they are referring to the “under foot” measurement. This width has the most effect on the ski's ability to edge, twist and also on its ability to float in powder or heavy snow.

Most technical or race skis are very narrow under foot (66mm – 72mm) as this allows the skier to tip the ski from edge to edge more quickly and with less effort. A good analogy for this is if you picture 2 triangles: 1 with a wide base and one with a narrow base. The top point of the triangle is the centre of your ankle and the lower points are both ski edges, with the base being the ski base. It makes sense that the triangle with the narrower base would require a lot less effort to tip over. This same principle applies when skiing. As such, I would suggest this narrower width for anyone participating in instructor exams, racing or high level skiers wanting to ski technically in bounds.

The downside to this width ski is that it is much more difficult to ski powder or heavier snow conditions as the ski tends to sink. For the bottomless powder fields of Japan or the big mountain back country of North America a much wider ski is required (100mm – 130mm under foot). This will give the base more surface area and consequently allow the ski to float more on top of the powder without getting bogged down. As you can imagine though, this width ski is rather useless on groomed trails as it is very difficult to edge.

A common trait of wider skis is skidding, particularly the first half of the turn. On the other hand, narrower skis can sometimes have the opposite effect of catching edges or producing a higher performance than desired (particularly for instructors performing slower demonstrations).

A compromise that covers all areas reasonably well is a “mid-fat” which has a width of  80mm – 100mm underfoot. As with the radius compromise, this ski does everything well but is not as good as a specific width for a specific task. The wider the better for off piste and powder, and the narrower the better for carving and dynamic skiing. For those participating in ski instructor exams or teaching skiing, I would suggest anything under 80mm, unless specifically teaching powder and off piste.

Length This can be a tricky one as we are all different weights and heights. Generally a shorter ski will be more manoeuvrable, easier to twist, lighter and more agile. This would mean that a shorter ski would be more suitable for a short radius turn. However, shorter skis tend to be less stable at higher speeds and less useful in deeper snow. Longer length skis usually pose the exact opposite pros and cons to the shorter length ski.

Typically GS style skis for men are a little longer (185cm  - 195cm) as they require stability at speed. This longer ski also provides a longer edge to maintain grip and pressure. An SL style men's ski would be 165cm – 170cm and would allow easier short radius turns. As with the different widths, for powder I suggest something slightly longer, to give more surface area to the base and subsequently better float.

Those going for a compromise should look at a length in between. Often a good length is slightly shorter than their own height (e.g. I ski 170cm - 174cm and I am 180cm tall). My suggestion is that you try skiing a few different lengths and find a length that best suits your skiing, teaching and any instructor exam tasks you are sitting.

Stiffness No matter what type of skiing you are doing the goal is to let the ski do as much of the work as possible. For this to happen, the ski must be tipped on edge and consequently bent into an arc to turn efficiently. There are 2 areas of stiffness that affect the ski's ability to do this: Flex along the length of the ski (usually referred to as “the stiffness” or “flex” of the ski) and the torsional stiffness/flex.

At faster speeds a ski will have more pressure acting on it. As such, it will require more longitudinal stiffness so that it doesn't collapse and bend into a noodle. Instead, a stiffer ski will give something back when under load in the way of rebound or spring. The torsional stiffness affects how well the whole ski stays true to its edge angle. When you tip the ski onto edge with your boot, you want the tip and tail of the ski to also tip up on edge. A torsionally soft ski will not do this very well and subsequently will have less edge angle at the tip and tail than it does at the boot. This is not so great as it provides less grip, less stability and decreases the ski's ability to bend into an arc. For all advanced skiers, regardless of the ski or terrain, I strongly suggest that you ski on a ski with strong torsional stiffness as you are going for grip and speed, and a torsionally stiffer ski facilitates this.

I often overhear instructors boasting about the stiffness of their equipment. Let me tell you right now that stiffer (longitudinal) does not always mean better. A ski that is too stiff will send you to the back seat, overwork your quads and generally feel uncontrollable. “World cup” race skis are made to be skied at “world cup” speeds and deal with “World Cup” amounts of pressure. These skis are far too stiff for recreational skiing and amateur racing.

For powder, a softer ski is more beneficial as it will bend more easily at slower speeds and also allow the tip to bend and stay afloat. The same rules apply to powder skis, as the speed increases so must the stiffness.

Stiffness is a difficult one to offer general advice on and describe. The best thing for every skier is to demo a few different skis to see what sort of stiffness is suitable for their skiing.

Summary I hope this information helps you when deciding a suitable ski for you. It is important to point out that I have included “the compromise” for each example, which a lot of ski brands market as the “all mountain” ski. Be aware that this ski will allow you to do everything at a consistently mediocre level. It doesn't let you down in any area but will never allow you to compete with your friend skiing the specific ski for that specific turn/terrain. On the flip side, those specific skis will let you down when performing anything that they are not specifically made for.

As for the brand: all ski brands make similar skis to their competitors. Some brands are slightly stiffer than others due to their construction and for this reason it is a good idea to demo a few different brands before you buy. No matter what ski you have, it is useless if it is not tuned and properly maintained. I try to wax and sharpen my skis at least once a week for best results. My race skis are waxed and tuned after every single use and my powder skis are tuned the least but regularly waxed. I usually carry a diamond stone with me at all times to knock off burs or marks on the ski edge that may occur throughout the day.

For those that are instructing, every snowsports school has ski reps within the school that will offer pro deals on the latest skis. Pro deals can work well for both parties, and certainly assist with significant savings off the general retail price.

Good luck with your ski selection, the right ski will make the world of difference to your skiing and enjoyment of the sport!

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