TPS Archives

Reprints From The Professional Skier

Fall 1999 - "Tracing Footprints All Over The Mountain" by Dave Merriam and Mike Porter

This article is reprinted from The Professional Skier. All copyrights apply. Please see our copyright and disclaimer notice page.

If you went to your dentist to get a root canal, wouldn't you be a little nervous if he or she looked at the implements lined up on that little tray and said, "Hmmmm, I wonder what this one is for?"

Well, you might elicit that same uneasy feeling among your students if you're not familiar with the general performance characteristics of any given type of ski they may want to try this season. After all, they expect you to know the tools of your trade.

These days there are more equipment choices than ever before, and different skis produce different sensations--and require subtle shifts in skills application--depending on skier ability and the prevailing terrain and snow conditions. But that doesn't mean you have to take every ski on the market out for a test spin.

To navigate through the maze of today's equipment options, start out by becoming more knowledgeable about the three basic design parameters of skis: waist width, turn radius, and taper. Measured in millimeters, waist width is how wide the skis are at their midsection (fig. 1 below). Turn radius represents the skis' optimum carving arc, measured in meters and determined, largely, by the depth of the skis' sidecut. Taper refers to the relationship between the width of the tip and the width of the tail, i.e., a ski with a wide tip and a narrow tail will have a larger taper than a ski with little difference between tip and tail widths. Think of these three things as personality traits that establish the skis' performance characteristics and set the stage for what the skier must do to make them work most efficiently.

In the following charts, we've categorized skis by waist width, turn radius, and performance characteristics, and have also outlined performance characteristics of various tapers. Use this information as a framework to guide your investigations and experimentations, keeping in mind that the characteristics listed are general assumptions rather than hard-and-fast rules.

Racing Skis

Waist Width: 60-64 millimeters
Turn Radius: 24-28 meters
Characteristics:

aAllow quick transition from edge to edge. Small lateral moves create instant edge angle adjustments and elicit immediate reactions from the skis.

aPromote a "skate-like" sensation; the slimmer the waist the more the ski performs like an ice skate.

aRequire precise edge adjustments. With these skis, you will find it more challenging to make fine-tuning adjustments once you've initiated a turn.

aCreate powerful edge hold. The narrow waist allows for a very strong edge grip, but this also can make it more difficult to release the edge to initiate a new turn.

aAre not very "floaty." In other words, the narrow waist limits the ski's ability to float in powder or crud. You'll need to maintain higher speeds to ski in soft snow conditions.

aMay require use of a lifter between the binding and the ski. With these narrow-waisted skis, you'll likely need lifters to keep your boots from dragging in the snow at high edge angles.

aAllow maximum performance from ski design and construction. Of course, to get the most out of these skis, you have to be able to give a lot. Because they require deliberate and accurate movements, you'll need to be in top physical condition to perform at a high level of proficiency all day long.

All-Mountain/Freeride/Midfat Skis

Waist Width: 65-74 millimeters
Turn Radius: 20-26 meters
Characteristics:

aHave a bigger platform. These skis are less sensitive to small lateral movements, making it easier to stay in balance.

aHave more capacity to float in softer conditions, powder, and crud. These skis ride on or close to the surface of the snow.

aAre less responsive to lateral movements than their high-performance counterparts. Because they are less dependent on precise movements, these skis are more forgiving in deep or heavy snow conditions than their narrow-waisted counterparts.

aRequire more lateral movement to edge the ski than narrow-waisted skis. These skis are less responsive than race skis but have more than enough controllability for all-mountain conditions.

aRelease the edge at turn completion more easily than skis with narrow waists. This makes for easier entry into the next turn.

aAre easier to skid than narrow-waisted skis. Off-piste conditions may demand that you "throw 'em sideways," and the wider waist and shallow sidecut give these skis a more balanced sideways skid.

aAre slower in short turns than narrow-waisted race skis. The turn takes longer to develop because they're not as quick from edge to edge, but in most all-mountain terrain, you don't require a racer's quickness.

aRequire less effort. You may have to sacrifice certain performance aspects, but the trade-off is that you don't have to put as much effort into your skiing.

aOffer good to excellent performance in the broadest range of snow types and conditions. Although they might lack some elements of precision, the benefits of forgiveness, float, and overall versatility make these skis the best all-round tools.

Backcountry/Powder-Specific Skis

Waist Width: 75+ millimeters
Turn Radius: 28-40 meters
Characteristics:

aFeature minimal sidecut, which lets the skier rather than the ski create the arc. In very soft snow conditions, these skis don't offer enough resistance for the sidecut to strongly affect turn shape.

aFloat on top of the snow for easy or high-speed skiing. These skis are great for those just learning to, ski powder or for athletes who like to rip long, high-speed arcs in steep terrain.

aPerform less like an ice skate, because the ski's edge is farther from the ankle.

aPerform less efficiently on hard and hard-to-soft transition snow. These skis don't have the edge-holding capability of narrow-waisted skis.

Performance Carving Skis

Waist Width: 60-64 millimeters
Turn Radius: 18 meters or less
Characteristics:

aOffer ample sidecut with a narrow waist. These skis are best used with big lifters. Some skiers use plates that are 30-50 millimeters high.

aAre popular in Europe with the "Boomer" generation. Because so many Europeans favor groomed pistes, these skis get high marks because they really shine when the run is buffed.

aAre "one-trick ponies," essentially. That is, this design lends itself to one size of turn or radius of the turn's arc.

Tip and Tail Relationship/Taper

Many ski designers and manufacturers refer to the relationship between the tip and the tail as the taper. The wider the tip relative to the tail the greater the taper. Narrowing the tip or flaring the tail can reduce taper, and this relationship can have a dramatic effect on how the ski performs.

Traditional Taper
The tip is 9 to 12 millimeters wider than the tail.

Characteristics:
aAllows the tip to pull through the turn; rewarding your forward/lateral movements with a cleaner turn initiation.
aAllow you to adjust turn radius with more or less tip pressure/edge angle.
aMake it easy to release the old turn and start a new one.
aEnable you to easily release the tail of the ski for skidding.
aRequire you to control the ski with fore/aft movements.
aEnable you to make both short-and long-radius turns.

Small Taper
Tip and tail dimensions may be the same. In general, however, the tip is 6 to 8 millimeters wider than the tail.

Characteristics:
aAllow both ends of the ski to support the turn. Both the tip and the tail contribute to turn radius, much like a four-wheel-drive vehicle simultaneously engages all four wheels.
aAllow you to use more of the ski. With the tip and tail both lending more support to the ski's middle section, the ski-to-snow contact is relatively substantial. In other words, much like an oversized tennis racquet or golf club, this type of ski has a large "sweet spot," which is more forgiving of imprecise movements.
aAllow you to stay on task. Once you start a turn the ski seems to want to stay engaged and keep turning. However, these skis tend to have one predominant turn radius.
aAre easy to operate. These skis provide a lot of confidence and security as you feel the skis are working for you rather than against you.

Large Taper
The tip is more than 12 millimeters wider than the tail.

Characteristics:
aOffer an extremely strong tip initiation if desired.
aEnhance the skier's ability to control turn radius, but geared toward experts because they're not very forgiving of imprecise movement.
aAllow you to release out of the turn very quickly.
aRequire precise control of fore/aft balance throughout the turn because they have a smaller sweet spot than small-taper skis.

Conclusion

By becoming more familiar with these general rules of thumb pertaining to waist width, turning radius, and taper--and the impact that variations in each can have on the performance characteristics of a ski--you'll be better prepared to make sense of all the new equipment options available to you and your students. After all, if you don't know the tools of your trade, how will you know if they're being used to their fullest potential?

Dave Merriam is the head coach of PSIA's education teams. He is the ski school director at Vermont's Stowe Mountain Resort.

Mike Porter is an at-large member of the PSIA Steering Committee. Porter is the ski school director at Vail/Beaver Creek Resorts in Colorado.