Ski design and length - design matters

[filojib]

After researching powder skis, looking at standard designs and new designs, I've come to the conclusion that you can't decide on length unless you take the design into account.  The trouble is that the available stats are usually not sufficient to tell you what you need to know.  For example, if you are looking at a "rocker" or "invert" design, such as a Spatula (Volant, rare), 11 (Birdos), Lotus 138 (dp), or Scoop (Goode), you need to know the running length (edge length) and another measurement, the name of which I don't know, but you can call it the flat surface contact length (bottom of ski in contact with a flat surface).  The same is true if you have a hybrid design, such as a Lotus 120 or a Pontoon (K2).  When you look at the lengths of some of the new design skis, you begin to understand that a 179 cm ski can ski like a 170, etc.  For example, Lotus 120s in 179 cm have a flat surface contact length of only 137 cm and Lotus 138s at 192 cm are nearer to 85 cm flat surface contact length (this is a guess).  Thinking about skis this way will help you decide on length, I hope.

Does anyone agree or disagree?

[jim-ratliff]

I agree and disagree.  I agree that some skis "ski longer" or "ski shorter" than their overall length, but I don't agree that you can measure that in any way other than skiing them.  Certainly, length of running surface gives some indication when you are on hard snow.  For example, 4-5 years ago Head changed their all-mountain skis to have a shorter upturned section in the shovel.  This caused a given length to have a running surface a centimeter or two longer.

However, when you are off the trail (on in soft snow even if you are on the trail), the entire length of the ski may be in contact with the snow.  Especially the Lotus design (to the extent that Michael can make me understand it), the entire length of the ski is in contact with the powder, and in fact the upturned tip and tail facilitate turns on soft snow by creating the camber associated with a turning ski (while the center section provides the normal decambered section that helps create grip on hard snow).

As far as determining flotation, Michael has posted formula's from Physics Man over on Epic that help calculate ski surface and therefore helps calculate relative flotation for different size skis and skiers and weights.  In those formulas, the running length is probably the more accurate number even though the contact surface on hard snow is quite a bit less.

[jbotti]

I agree totally. I think this effect is much greater in reverse camber skis. When these skis are on hard surfaces only the mid part of the ski is touching the snow. I think this effect is evident to a smaller degree in twin tip designs which also ski smaller than the stated length.

If you look at ?DP www.dpskis.com they do actaully give meausrements. They say the running lenghth of the Lotus 138 is 164.5cm and that the forebody is 60cm and the tail body is 50cm and the tail length is 3.8cm. I actually don't know what any of these measurements actually mean other than running length (which I think is what most should focus on when choosing a ski of this sort). I have odered a pair and I understand that they do ski short. Hopefully I will have mine in 2 weeks and I can post a review. JB.

[filojib]

I'm expecting 120s sometime in December.  Still thinking about the 138s.  Would you mind commenting when you ski 'em? I'll do the same.  Like to see a company like this make it!  Even with the info that dp provides, you have to do some guesswork to determine what part of the ski is on the snow.  jbotti is right about the kind of snow making a difference, too.  The cool thing is that you want extra length in the deep and don't need as much in the less deep, and these designs, especially the hybrid rocker tip, seem to deliver on that.

[scottpetill]

I'm 5'11" 155lbs. I like to move at medium speed on loose and soft snow/soft bumps I like to pick my way through, hitting as many *soft bumps* as possible. I prefer less than GS speeds on groomed and instead seeks the edges near trees and make a lot of medium radius turns, playinig with the snow. I also seek out chutes when they're not hard packed, but again I don't *charge* through.

I recently demo'd Dynastar 8800's at the Bird in both 168cm and 178cm. I immediately found the 168 size to ski similiarly to my Troublemakers (175cm) in terms of quickness, lightness and speed but much more stable on hard pack/run-offs and the ice grip was much better. When I ran the 178's I found them much speedier and less nimble in the bumps than the 168's. The difference was suprisingly obvious. The bigger ski really moved while the 168's stayed more in my comfort zone. I tried to ski them all through the same lines as best I could.

While the 168cm felt really nice I did not get to try them in untracked powder. Will the shorter ski perform less than ideal for me at my height/weight in the fresh? I'm thinking of purchasinig the 8800's at 168cm, though most tech's would recommend the 178's based on my height.

Thanks

[filojib]

Scott

I think that the longer skis will definitely serve you better in fresh.  They might help you move your "comfort zone" a little to the right, if you are so inclined
.  I am 5'5" and weigh 135 lbs.  I am 58 yrs. old and cut down some years ago to skis in the 165-168 zone.  They helped me step up my skiing considerably.  Stockli Stormriders, 1080 Guns.  Eventually, I wanted to up my style factor to add more speed and more dicey moves in crud and steeps.  So, I bought a pair of 174 K2 Apache Outlaws (125/88/110).  They measure more like 179, but have some tip rocker and ski shorter.  I eventually added some DPS Lotus 120s at 179, a pretty pure powder ski with minimum sidecut.  What a difference.  I found the Outlaws work fine in bumps, powder and groomed. They absorb piles of crud, bumps, etc. much better than the shorties.  They go fast if you want them to, but are surprisingly nimble.  The extra length actually controlls speed in bumps if you keep them on the snow.  The DPs are a completely different story.  A specialized design for deep snow, "for the best days" as DP says.

When there hasn't been any new snow for a while, like we are experiencing now in Utah, I like to go back to the Stocklis and have some fun in the bumps.  Shorter is definitely more fun and safer on steep, hard snow or icy bumps, where there are consequences to falling and sliding.  With your height and weight, I think 178 qualifies as "not long", but it depends on your ski style and what you are trying to achieve with your skiing.  Hey, nobody says you have to push.  Have fun out there.  Hope this helps.

[scottpetill]

Thanks for the insightful reply.

I think I need to demo more skis at various lengths and perhaps I just need to give the longer 8800's, or similar fast skis, a little more time to acclimate myself to them.

My short-term goal is to replace my T'makers ASAP with something more stable and I remember my first turns on the 8800's at 168cm made me feel more confident on hard packed steeps and crud as they held where the T'makers would slip or flutter. Perhaps they would make a good transition to a longer and faster ski for as you've noted they allowed you to step up your skiing. The Dynastar Mythic Rider sounds interesting, too. Same waist and construction as the 8800 but more side cut.

Thanks again.

[filojib]

Right on all counts.  Note that curved tips and tails, typical on "big mountain" and "powder" skis will make the the stix ski "shorter" than a conventionally designed ski of the same "length".  Thus, "design matters."  The real question is, as always, "compared to what?"  It's very difficult to compare skis, except in the store where you can actually put them up bottom to bottom and look at them.  I suggest doing this for fun - assuming you like looking at skis in stores.  Who doesn't?  Of course, demoing is going to make a difference, but that's hard to do unless you live near a great reasort.  Happy skiing!