New Skis Concave

[Noodler]

Per Eric Pollard of Line Skis: With this convex contouring, we’re able to loosen the overall feel when the tip or tail is pressured. Similar to a surfboard, the convexity adds dimensionality to the ways is which you can pressure, feather, and stand on a ski. The end result is a ski that slashes better, butters with more control, improves float, and adds speed.

Not my wheelhouse, but it sounds intriguing.

Sounds interesting, BUT only as long as you're in untracked deep 3D snow. In anything else I wonder how much of a liability that design becomes. Kind of like Shane on the water skis doing big lines in AK. You wouldn't want those to use for inbounds resort skiing.

 

[neonorchid]

At the shop I'm around most, this spring, every wider Volkl V-Werks in stock (Katanas and Mantras), and a new pair of such Mantras I brought in myself, were badly concave. On close inspection, we found they were warped, uneven, right up to the edge without being particularly "edge high," by Doug's definition. The bases thus "peaked" at the edges in waves or ripples, the whole way: enough that when a ski was worked on for base flattening, it formed what are known as "bird bath" ovals, in "pools" along the base, and in smaller metal ovals along the side edges. At least 1 mm deep concave also.

All current in stock 18/19 Volkl V-Werks- half new Mantras and half Katanas.

And, with the pair we inspected more closely, my own, the skis were both irregularly off in the same way, as if out of the same lopsided mold from the factory, or the same "off" tuning machine/technician.

Did the shop send all of them back to Volkl?

 

[Ross Biff]

They should market convexivity as "side rocker"..

I see what you did there! How would a shop set up a grinder to maintain side rocker during a machine tune?

 

[ARL67]

DSP has been offering a few wide pow-specific skis for several years with their convex base at the tip, they call the feature "Spoon".

A review from Blister:
https://blisterreview.com/gear-reviews/2013-2014-dps-spoon

 

[neonorchid]

Line Outline Convex tip and tail - https://blisterreview.com/gear-reviews/2019-2020-line-outline

 

[Jacques]

@Tom K. what would be the benefit of convexity?

Here would be an example of a convex benefit. Also good for powder skiing.

 

[LiquidFeet]

Nevermind; I misread and thus miscommented.

 

[ski otter 2]

As I can see in that video, a bit of convexity tip and tail adds mild forgiveness, call it the "boat prow effect." Nice "sailing," @Jacques!

It is good in old snow conditions too, for day to day skiing, and yet - go, Jacques!!!!!!

 

[Jacques]

As I can see in that video, a bit of convexity tip and tail adds mild forgiveness, call it the "boat prow effect." Nice "sailing," @Jacques!

It is good in old snow conditions too, for day to day skiing, and yet - go, Jacques!!!!!!

Yea, I don't mind a ski with a bit of convex tip and tail. I do like them good and flat under foot though.

Know what you like. Know when you like what you have to choose from. Choose what you like for the conditions at hand.

 

[Noodler]

Yea, I don't mind a ski with a bit of convex tip and tail. I do like them good and flat under foot though.

Know what you like. Know when you like what you have to choose from. Choose what you like for the conditions at hand.

Good point that hasn't been stressed in this thread. It is critical that the ski be dead flat underfoot; at least a couple inches ahead of and behind the binding components.

 

[Jacques]

Good point that hasn't been stressed in this thread. It is critical that the ski be dead flat underfoot; at least a couple inches ahead of and behind the binding components.

Good advice. I'd mostly agree.

 

[ski otter 2]

With fat skis, this is almost never the case, for the length of the skis even more so. But they often ski fine, if enough base in from the edges is flat. (I suspect @Jacques might agree with this, but not sure.) Not sure if it's critical that underfoot on a fat ski be dead flat instead of flat in a fair distance from the edges, but maybe. Guess I'll learn something if I've been wrong about this.

I am a real fan of flat base skis. Especially thinner skis. And I've known the hard way repeatedly what a rail high ski feels like - no fun.

But in my experience, what fat skis often need is what @Doug Briggs said above, post #3. From half inch to an inch in from the edges flat usually works well, depending on the ski. Maybe try that to see if that is effective; so as not to take too much off the base, and shorten the life of the ski unnecessarily. (See post @jmeb #2 on base thickness.) In many cases, insisting on really flat bases with a fat ski will just mean premature aging of the ski needlessly, often.

Yes, ideally, maybe dead flat underfoot, mostly. But fat skis especially are just routinely uneven, with rail high places often too deep to flatten completely, practically speaking; and they often ski just fine when flattened enough.

Note: Having bases flattened by hand (as @Jacques does - or used to, at least - in his business), or base flattening one's own skis, are good ways to end up with skis that are base flat or closer to base flat, when practical. Too many shops routinely hand back machine flattened skis that are rail high and poor performing, in my experience, as I mentioned above.

 

[Noodler]

With fat skis, this is almost never the case, for the length of the skis even more so. But they often ski fine, if enough base in from the edges is flat. (I suspect @Jacques might agree with this, but not sure.) Not sure if it's critical that underfoot on a fat ski be dead flat instead of flat in a fair distance from the edges, but maybe. Guess I'll learn something if I've been wrong about this.

I am a real fan of flat base skis. Especially thinner skis. And I've known the hard way repeatedly what a rail high ski feels like - no fun.

But in my experience, what fat skis often need is what @Doug Briggs said above, post #3. From half inch to an inch in from the edges flat usually works well, depending on the ski. Maybe try that to see if that is effective; so as not to take too much off the base, and shorten the life of the ski unnecessarily. (See post @jmeb #2 on base thickness.) In many cases, insisting on really flat bases with a fat ski will just mean premature aging of the ski needlessly, often.

Yes, ideally, maybe dead flat underfoot, mostly. But fat skis especially are just routinely uneven, with rail high places often too deep to flatten completely, practically speaking; and they often ski just fine when flattened enough.

Note: Having bases flattened by hand (as @Jacques does - or used to, at least - in his business), or base flattening one's own skis, are good ways to end up with skis that are base flat or closer to base flat, when practical. Too many shops routinely hand back machine flattened skis that are rail high and poor performing, in my experience, as I mentioned above.

Please define "fat".

 

[James]

Worst ski I've ever demoed was 94mm. Unskiable and dangerous.

 

[CalG]

Worst ski I've ever demoed was 94mm. Unskiable and dangerous.

revealing......

 

[LiquidFeet]

Worst ski I've ever demoed was 94mm. Unskiable and dangerous.

More info, please.

 

[Dakine]

I have a pair of 2006 factory race Atomic LT-12's and they are constructed conventionally.
Atomic routed a small channel in the tops and rounded the corners so they look like Beta construction.
176 and >21m radius, a great pair of GS skis.
I still use them sometimes when I have a need for speed.
They are as flat as a pancake.

 

[Jacques]

With fat skis, this is almost never the case, for the length of the skis even more so. But they often ski fine, if enough base in from the edges is flat. (I suspect @Jacques might agree with this, but not sure.) Not sure if it's critical that underfoot on a fat ski be dead flat instead of flat in a fair distance from the edges, but maybe. Guess I'll learn something if I've been wrong about this.

I am a real fan of flat base skis. Especially thinner skis. And I've known the hard way repeatedly what a rail high ski feels like - no fun.

But in my experience, what fat skis often need is what @Doug Briggs said above, post #3. From half inch to an inch in from the edges flat usually works well, depending on the ski. Maybe try that to see if that is effective; so as not to take too much off the base, and shorten the life of the ski unnecessarily. (See post @jmeb #2 on base thickness.) In many cases, insisting on really flat bases with a fat ski will just mean premature aging of the ski needlessly, often.

Yes, ideally, maybe dead flat underfoot, mostly. But fat skis especially are just routinely uneven, with rail high places often too deep to flatten completely, practically speaking; and they often ski just fine when flattened enough.

Note: Having bases flattened by hand (as @Jacques does - or used to, at least - in his business), or base flattening one's own skis, are good ways to end up with skis that are base flat or closer to base flat, when practical. Too many shops routinely hand back machine flattened skis that are rail high and poor performing, in my experience, as I mentioned above.

I still routinely flatten bases with a steel scraper. (a very sharp one!)
I think your post is pretty much true.
A dedicated powder ski can be just fine even if it is convex.

 

[Dakine]

Jacques...do you burr your scraper when you flatten?

 

[James]

More info, please.

Originally posted here, but I've changed it a bit.

Rented a pair of 180 Bizzard Rustler 9's, 94 underfoot, in Chamonix. Went skiing after a 5 min walk plus 15-20 min bus ride to Prarion in Les Houches It's taining till about halfway up. Then graupel. .

Got off the gondola and descended down a flat traverse. Immediately the skis force themselves into a wedge. I thought maybe there's ice on the boots. Stop, clean them off. Skis just as bad. They don't want to turn, have a chaotic mind of their own. The snow is graupel coming down an inch and a half , over compressed wet snow with a glaze and endless random small bumps. So it's also sticky. I stop again and go over all base edges with a diamond stone.I've carried it for a week for this situation and never used it. Maybe it's a hanging burr.

No, the skis are just as bad. Basically unskiable, dangerous. Especially since I'm tired after 7 straight days plus travel. Often with grippy bases you can throw them forcefully feom edge to edge, minimizing any low angles at transition. That doesn't work here partly because of the snow too. Dangerous because I really don't know what the ski will do. Even a quick hockey stop could be a big problem.

It's raining at the bottom, but I go all the way down to the bottom, walk across the street and pay a different ahop to rent a pair of 168 Stockli Ax. At least they worked.

Probably the worst tuned ski I've ever demoed, and there've been some bad ones. Maybe it was a combo of convex, concave with some edge high spots. Don't know. This situation is difficult to get across in English, never mind in bad French. General tuning knowledge is even lower in France/Switzerland I've found.

It's also occurrd to me since maybe the bindings were off center or skewed to the center line. Because of the instant wedge behavior. In addition to the base issues.