Is tip-rocker always a good thing?
Posted: Sun Jan 15, 2017 3:34 pm
I am wondering whether others have thought about tip-rocker with a critical mind.
Rocker is an amazing thing. I am not suggesting it isn’t. But, is it an asset to every ski, in every context?
I have always been blown away with the simply wonderful performance of skis with tip rocker when downhill skiing- especially on deep, soft, fresh snow. Even on hardpack, a rockered tip reduces the effective edge and facilitates turn initiation (my boot feels like it is mounted further forward than it actually is), and as a result it also reduces the turn radius of the ski. A rockered tip also helps prevent tip-dive when skiing on deep snow, with a forward mounting point.
When it comes to early tip rise though, I have realized that a ski must be floating high enough in the deep snow in order for the rockered tip to be effective. In a down-hill context, this is rarely an issue, because you are travelling at enough speed, that even a modest-width ski is going to rise and plane in deep snow if it has a fully-rockered tip.
But- what about breaking trail through truly deep soft snow in a backcountry cross-country context? What I am discovering is that unless a ski has enough surface area to float near the surface of the snow- a rockered tip can actually be a liability when XC skiing through truly deep soft snow. When XC breaking trail through the deep pow, one is rarely travelling fast enough for the ski plane- therefore, a ski that does not have enough surface area to float- sinks. And, if the ski sinks, and has a rockered tip that wants to rise, the ski becomes completely unstable, and is often stuck in strange, unstable and completely inefficient angles.
Some examples with the kits I am currently skiing on in my local hilly backcountry (bear in my mind that I weigh 185lbs without any gear):
1) My 145cm Hoks float very effectively, and as such the rockered tips do rise and help keep the entire ski floating on top of the snow as they XC glide.
2) My 195cm Annums float quite effectively, but as the tip is low-profile, and not rockered, the tip usually stays beneath the snow if I am XC breaking trail through very deep, soft snow.
3) My 205cm Eons do not float on very deep soft snow. This ski has a soft flex overall- but, the tip and tail are very soft. When XC trail-breaking in deep soft snow, the waist of the Eon sinks deep into the snow, with the tip and tail floating higher up in the snow- YUCK- HATE IT.
4) My 205cm E-109s do not float on very deep soft snow. This ski has considerable Nordic rocker in the tip, but has a stiffer, flat tail. In very deep soft snow, the open tips want to rise, leaving the rest of the ski buried in the snow. It creates a sensation as if you are always on a slight incline, trying to climb your way up and out on to the top of the snow. I keep feeling- “if I could only glide fast enough, these skis would plane and rise up to the top”. Of course I never XC ski fast enough in very deep snow for the E-109 to plane- you are left feeling like you are breaking trail with the waist of the ski. YUCK.
5) My 210cm E-99s actually feel more stable than the E-109 in very deep soft snow. I think it is a product of the narrower tip not floating and rising as much. But- on the flip side, the extra camber and stiffness underfoot is more difficult to control than the softer flex of the E-109 in very deep soft snow.
6) My 210cm Combat Natos do not float on very deep soft snow either. They have no tip rocker of any kind. This ski- though having a softer tip and tail than its cambered midsection- has an overall flex that offers stability throughout its length. Although this ski still sinks in very deep soft snow, it is very stable, along its entire length- therefore, it breaks trail very effectively. (As an aside- its kick-ass broad, raised tip also helps- ALOT).
The physics of this are obviously both complicated and complex. But- ski manufactures seem to be adding tip rocker to most every ski these days- and I wonder whether it is always an asset to every ski. What do you think?
Rocker is an amazing thing. I am not suggesting it isn’t. But, is it an asset to every ski, in every context?
I have always been blown away with the simply wonderful performance of skis with tip rocker when downhill skiing- especially on deep, soft, fresh snow. Even on hardpack, a rockered tip reduces the effective edge and facilitates turn initiation (my boot feels like it is mounted further forward than it actually is), and as a result it also reduces the turn radius of the ski. A rockered tip also helps prevent tip-dive when skiing on deep snow, with a forward mounting point.
When it comes to early tip rise though, I have realized that a ski must be floating high enough in the deep snow in order for the rockered tip to be effective. In a down-hill context, this is rarely an issue, because you are travelling at enough speed, that even a modest-width ski is going to rise and plane in deep snow if it has a fully-rockered tip.
But- what about breaking trail through truly deep soft snow in a backcountry cross-country context? What I am discovering is that unless a ski has enough surface area to float near the surface of the snow- a rockered tip can actually be a liability when XC skiing through truly deep soft snow. When XC breaking trail through the deep pow, one is rarely travelling fast enough for the ski plane- therefore, a ski that does not have enough surface area to float- sinks. And, if the ski sinks, and has a rockered tip that wants to rise, the ski becomes completely unstable, and is often stuck in strange, unstable and completely inefficient angles.
Some examples with the kits I am currently skiing on in my local hilly backcountry (bear in my mind that I weigh 185lbs without any gear):
1) My 145cm Hoks float very effectively, and as such the rockered tips do rise and help keep the entire ski floating on top of the snow as they XC glide.
2) My 195cm Annums float quite effectively, but as the tip is low-profile, and not rockered, the tip usually stays beneath the snow if I am XC breaking trail through very deep, soft snow.
3) My 205cm Eons do not float on very deep soft snow. This ski has a soft flex overall- but, the tip and tail are very soft. When XC trail-breaking in deep soft snow, the waist of the Eon sinks deep into the snow, with the tip and tail floating higher up in the snow- YUCK- HATE IT.
4) My 205cm E-109s do not float on very deep soft snow. This ski has considerable Nordic rocker in the tip, but has a stiffer, flat tail. In very deep soft snow, the open tips want to rise, leaving the rest of the ski buried in the snow. It creates a sensation as if you are always on a slight incline, trying to climb your way up and out on to the top of the snow. I keep feeling- “if I could only glide fast enough, these skis would plane and rise up to the top”. Of course I never XC ski fast enough in very deep snow for the E-109 to plane- you are left feeling like you are breaking trail with the waist of the ski. YUCK.
5) My 210cm E-99s actually feel more stable than the E-109 in very deep soft snow. I think it is a product of the narrower tip not floating and rising as much. But- on the flip side, the extra camber and stiffness underfoot is more difficult to control than the softer flex of the E-109 in very deep soft snow.
6) My 210cm Combat Natos do not float on very deep soft snow either. They have no tip rocker of any kind. This ski- though having a softer tip and tail than its cambered midsection- has an overall flex that offers stability throughout its length. Although this ski still sinks in very deep soft snow, it is very stable, along its entire length- therefore, it breaks trail very effectively. (As an aside- its kick-ass broad, raised tip also helps- ALOT).
The physics of this are obviously both complicated and complex. But- ski manufactures seem to be adding tip rocker to most every ski these days- and I wonder whether it is always an asset to every ski. What do you think?
