How To Select Skis

Phil Smith, director of Snoworks reports on how to select the most suitable skis.

It’s simple to select a pair of skis. The first thing to remember is they’re all good, all turned up at the front, all have slippery soles and all have metal edges. But it can go horribly wrong and you can end up with a pair of skis that just do nothing for your skiing. On the other hand, get it right and you could see your skiing literally take off.

To select the most suitable skis for your skiing you need to ask yourself just two simple questions:

What sort of terrain do I like to ski?
What sort of speeds do I like to ski at?

Terrain can be split into three categories – Piste, All-Terrain, Off-Piste
Speed can be split into three categories – Slower, Medium, Faster

1. Firstly decide on the type of terrain you wish to ski and match this to the width of the ski underfoot.
On the skis or the manufacturers website the dimensions of the tip middle and tail are shown in mm. Take a ski with these dimensions  128 / 87 / 115. The middle number is always the width underfoot, in this case 87mm. We have divided the width under foot into three categories and matched this to the type of terrain you wish to ski.

Less than 85mm underfoot
The narrower the ski the more suited for on-piste. Slalom skis and racing skis are normally around 65-67mm underfoot. Many piste skis are around the 70mm to 80mm width. The closer you get to 85mm the more suited to all-terrain the ski becomes. You can still ski narrower skis in all-terrain and off-piste if you are really experienced but the narrower the ski the more difficult it is to use as the snow become soft or deep.

85mm to 100mm underfoot
The majority of all-terrain skis sit in this category along with many skis that are recommended for off-piste. Don’t forget off-piste is part of all-terrain. So if you looking for an off-piste ski that you also want to use everywhere then it will come in this category.  The closer to 85mm the more suited for piste skiing, the closer to 100mm the more suited for off-piste.

Over 100mm underfoot
Anything over 100mm and you’re looking at out and out off-piste (deep snow). The closer to 100mm the more suited to all-terrain. The wider the ski underfoot the more suited to deep snow and these days you can go wider and wider and wider. Don’t forget the wider the ski the less suitable for all-terrain and pistes. If using very wide skis on piste there is a more leverage on the knees as the skis try to flatten on the firm snow. So remember really wide skis are for off-piste where you are skiing in the snow rather than on it.

2. Secondly decide on the speed you like to ski at and match this to the sidecut radius of the ski.
The sidecut radius is shown on the skis or the manufacturers website. The sidecut radius is not the turn radius but affects it. The sidecut radius is purely the geometrical shape of the side of the ski. We’ve split the sidecut radius into three categories and matched it to the differences in speed.

This is a generalisation as many slalom skiers ski pretty fast on skis with sidecuts less then 15m. It’s also possible to ski slower on skis with sidecuts over 30m. We’ve purely used this framework as a guideline and created the template from racing using the disciplines of Slalom, Giant slalom, Super G and Downhill. Both the speed and sidecut radius increase as you move from Slalom to Giant Slalom to Super G to Downhill.

Sidecuts vary immensely depending on the length of the ski. So the same ski in different lengths will have a different sidecut radius. So all you may need to do to change the sidecut radius is change the length of the ski.

Less then 15m Sidecut Radius
This is a pretty tight sidecut radius and is great for anyone interested in carving tighter curves or skiing at slower speeds. If you’re a pretty competent skiers you can use these skis to travel at higher speeds as well. Out and out slalom skis for adults have sidecuts around 12m. Don’t forget there are always exceptions to the rule.

15m to 20m Sidecut Radius
Great for anyone who likes to carve medium radius curves and travel at medium speeds. Again if you’re pretty competent you can ski slower or faster on skis with this sidecut. A Giant Slalom ski for adults can be anything from 15m to 30m. 30m is World Cup. I ski on GS skis that have a 15m radius. I know, I’m a whimp! But I like my skis to come around easily.

Over 20m Sidecut Radius
Big turning skis for those that like to travel at high speeds and carve big curves. You can always travel at slower speeds on these skis but you won’t be able to ‘carve’ tight curves. Trying to ‘carve’ tight curves on these is like using a giant slalom ski to ski slalom – it doesn’t work well. But if you want to ski fast, then these are for you.

Selecting A Suitable Ski
So putting the three types of terrain with the three different speeds you have nine categories. What you do is simply match the two criteria ‘width underfoot’ and ‘sidecut radius’ and come out with the suitable skis. It’s not an exact science so you can make adjustments wherever you choose.

Exceptions To The Rule
As always there are exceptions to the rule and the more competent skier you become the more skis you can use competently in the different types of terrain and at different speeds.

Ski Stiffness
One extra design to bear in mind is ski stiffness. When skiing deep snow and not on a firm base the sidecut radius does not affect the turning radius. It’s the stiffness of the ski. Therefore the slower you wish to ski in deep snow the softer the ski needs to be, and the faster you wish to ski in deep snow the stiffer the ski needs to be. (Don’t forget there are always exceptions to the rule). This applies in all types of terrain and especially on firm snow when looking for great edge grip. Racing is an example of this. The stiffer the ski the better it is at gripping on firm snow (providing you have sharp edges) but the more difficult they are too turn.
Unfortunately there’s not a universal measurement for ski stiffness yet so we’ve not included ski stiffness into these guidelines! We’ll let you know when there is one.

Length
Another variable to bear in mind. But these days we ski on all different lengths. For example my 14 year old son skis on 157 Slalom, 182 Giant Slalom and 200 Super G. Don’t forget simply by changing the length of the skis you change the side cut radius. So often a skier may say they did not get on with a particular model or make of ski but it may have been purely the wrong length.

Want to learn how to use different skis. Join a Snoworks Course.

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