How Sidecut Still Matters in The Age of Rocker
I don’t want to come off as some geezer who gets misty recalling the olden days, but there was a time when a ski was expected to make contact with the snow from tip to tail, give or take a few centimeters. Now that we are firmly entrenched in the era of rockered skis, this notion sounds quaint if not downright antediluvian. Many modern tips aren’t made to engage with a flat snow surface, as if disdaining any snow that didn’t have the decency to rise to their elevation. Some bob around looking for loose snow like a bloodhound snuffling around for a scent, while others jut sharply out of the snow like the imperturbable prow of the Queen Mary rising above the waves.
The best rocker forebodies don’t call attention to themselves in any way – they simply assist in riding over uneven terrain in any of its incarnations. The rockered forebody blends with the rest of the ski when tipped and flexed, creating the impression that the ski is connecting with the snow throughout its length, just as in days of yore. But this is relatively rare behavior; most rockered skis steer as though the connection with the tip has been disabled, particularly at the top of the turn.
Now Rossignol has gone the next logical step and turned the entire tip into a decorative feature. The front ends on the new 7 series models look like they’ve been perforated by the same folks who designed the latticework on cathedral windows. It’s not that the new tips do nothing – they do, after all, intercept the snow surface in advance of one’s boots – but their contribution to a carved turn occurs below the level of human sensation. In every palpable sense, a reasonably executed ski turn begins only where the ultralight tip ends. This may sound like a serious demerit, but the wider skis in this series, the Super 7 and Soul 7, handle exquisitely. The implication is that as long as you build a great ski behind it, you can make the tip out of whatever sort of lightweight bumper material you like.
Not content to disarm one extremity, Rossi converts the last 10% or so of the ski into the same honeycomb construction used on the tip and, just to make sure it stays out of trouble, tucks the translucent tail inward. The radical taper at the end of the ski ensures that the effective sidecut radius (17m in a 180cm) ends where the tapered tail piece begins.
If you flip a Soul 7 over, it’s easier to see that the sidecut that engages the edge underfoot ends abruptly where the cathedral-window tip and tail begin, essentially excusing the tip from its traditional role in leading the rest of the ski into the arc and releasing the tail from the turn before running out of surface area. Now that some sort of rocker is de rigeur on any ski fatter than 80mm underfoot, how sidecut and rocker interrelate – as in the case of the Soul 7 – provides an interesting predictor of behavior. On this ski, nearly ¼ of the length of a 188cm is devoted to tip and tail sections that play no role in its turn engagement, creating big-ski flotation without requiring major acreage to complete a turn. Clever.
Let’s take the case of another ski with distinctive tip, mid-body and tail performance behaviors, the Dynastar Cham series. Take a look at the tail of the Cham 107: the last 25cm of a 190cm has no influence on turn shape, unless you count running for the barn as a turning motion. As with the 7 series, the sidecut the skier actually engages creates a tighter radius than what the ski’s length would normally indicate. Again, not a problem, but it’s something to be aware of: the Cham skis, particularly those with metal, want to stay in the fall line where they have a GS platform blended with SL turn-shape DNA.
Speaking of twisted threads, the point of this monogram is that the Age of Rocker has not totally nullified the importance of sidecut in determining ski behavior. True, rockered skis do not perform like the carving skis of a decade ago, but while a ski’s sidecut may no longer start at the tip and end at the tail, what sidecut remains is still a predictor of a ski’s behavioral preferences. But only a predictor. At the end of the day, a ski is more than the sum of its sidecut plus its rocker plus its stiffness; i.e., it’s not just a shape that flexes. A ski is everything that goes into it. Witness the case of the aforementioned Cham series from Dynastar. The Cham 107 sports two sheets of metal, while the High Mountain iteration of the same ski deletes them to create a lighter option. That one change creates a multitude of feedback differences, allowing the High Mountain model to be more supple and forgiving. There is no voodoo in ski design; everything happens for a reason. The recipe for a great ski is like any great recipe: change any one detail and a flavor is lost or added. And regardless of the recipe, it takes a great chef to bring it to brilliant life.
– Jackson Hogen
