Skis w/ metal vs. skis w/o metal

[David Chaus]

ON3P Wrenegade 108 is pretty stout. The regular version does not have metal.

With it's bamboo core any of the ON3P skis are damp for their respective category: Wrenegade -> directional charger, Woodsman -> All Mountain, Jeffrey -> Freestyle

I had the opportunity to demo the Woodsman 108 while in Big Sky (East Slope in the Town Center carries ON3P), definitely a solid ski, less of a charger than the Wrenegade, definitely more nimble in tight places, trees, bumps, and comes alive in soft snow, however still very solid and damp.

 

[cantunamunch]

With metal layers = almost always damp
Without metal layers = cannot be assumed that it is not damp

The Hart Pulse is another example of a ski without metal that is remarkably damp.

Sure, but the causation has been presented bass ackward in this thread.

Metal doesn't damp squat by itself and every tuning fork and every bell proves it.

If we see metal as a tool to give feel and response to otherwise lifeless or limply damp skis, your conclusions drop out pretty naturally as a consequence.

 

[AngryAnalyst]

Sure, but the causation has been presented bass ackward in this thread.

Metal doesn't damp squat by itself and every tuning fork and every bell proves it.

If we see metal as a tool to give feel and response to otherwise lifeless or limply damp skis, your conclusions drop out pretty naturally as a consequence.

I doubt many people believe metal by itself does anything. Skis are, by nature, composite objects.

I do believe pretty strongly that skis with all of rubber or another elastomeric layer, metal, fiberglass and wood are usually damper than skis without at least one of those ingredients. Given the practical impossibility of trying any significant fraction of the skis that exist and which might work for me, I think I need a heuristic to give some general guidance for what skis to try. That said, I’m always open to suggestions for possible exceptions to my heuristic.

 

[cantunamunch]

I do believe pretty strongly that skis with all of rubber or another elastomeric layer, metal, fiberglass and wood are usually damper than skis without at least one of those ingredients. Given the practical impossibility of trying any significant fraction of the skis that exist and which might work for me, I think I need a heuristic to give some general guidance for what skis to try. That said, I’m always open to suggestions for possible exceptions to my heuristic.

This thread is a knife edge away from cargo cult thinking about metal.

"If metal must be damp" is entirely parallel to "If we clear grass landing strip and make a tower with wooden aerials, airplanes will land again"

I believe pretty strongly that most skiers can't tell a highly damp stiff ski from a stiff ski with low rebound - and no one even pretends to like highly damp soft skis.

As an example - the elastomers you mention - well, they're in just about every alpine ski made (except for the very cheapest), between the edges and the core. Except, funny enough, they have a preferred damping frequency (somewhere in between 100 and 150 Hz) and they get worse (less damp) as temperatures drop. Have you seen anyone in any thread ever mention their skis getting less damp as the temps drop down below 5F? Me neither. And yet the material with by far the strongest damping characteristic in their skis -put in for exactly that purpose - has just such a rolloff.

Note that if skiers aren't sensing damping at all but are sensing stiffness and rebound speed, your heuristic may actually be a better fit.

 

[KingGrump]

Have you seen anyone in any thread ever mention their skis getting less damp as the temps drop down below 5F?

Don't know whether my skis get less damp below 5F. I know my body definitely stiffen up below 5F.

 

[David Chaus]

Funny, my body really started stiffening after 50.

 

[cantunamunch]

Funny, my body really started stiffening after 50.

Yeh, we really don't want to hear about how much damper it got tho.

 

[Fuller]

This thread is a knife edge away from cargo cult thinking about metal.

I had to look it up but I learned something today!

 

[Jimski]

This thread is a knife edge away from cargo cult thinking about metal.

Huh, so in 2015, when I switched from a Blizzard Bushwacker to a Volkl Kendo, and the latter was much more quiet and less vibrating on steep hardpack, that difference was not due to the titanal in the Kendo? Wow!

 

[cantunamunch]

Huh, so in 2015, when I switched from a Blizzard Bushwacker to a Volkl Kendo, and the latter was much more quiet and less vibrating on steep hardpack, that difference was not due to the titanal in the Kendo? Wow!

A completely un-damped 6 foot piece of #18 rebar will vibrate less than your Kendo when struck by the same impact.

Thank you for demonstrating my above point - that skiers do not differentiate between the quantity "damping" and the combined quantities "stiffness and rebound".

 

[Jimski]

Thank you for demonstrating my above point - that skiers do not differentiate between the quantity "damping" and the combined quantities "stiffness and rebound".

With respect, how did I prove your point? In my previous post, I said nothing about rebound. In fact (IIRC), the Bushwacker rebounded fine. The issue for me was that they chattered on steep hardpack and didn't absorb "jolts" in mixed snow as well as the Kendo. I (and most ski reviewers, who know more than me) call that characteristic "damping". If you want to call it something else, go for it.

 

[cantunamunch]

With respect, how did I prove your point? In my previous post, I said nothing about rebound. In fact (IIRC), the Bushwacker rebounded fine. The issue for me was that they chattered on steep hardpack and didn't absorb "jolts" in mixed snow as well as the Kendo.

Right there, you did it again. A stiffer ski with a slower rebound speed does all that - even though it might dissipate less energy per vibration cycle than the softer ski. Damping only tells you how much energy is lost per vibration cycle. https://en.wikipedia.org/wiki/Damping_ratio

I (and most ski reviewers, who know more than me) call that characteristic "damping".

Proving my point yet again. Notice that the ski designers I linked to above do not call that characteristic "damping"

Vibration Damping and Skis

“Vibration damping” has become a popular, often misused, term in many industries including skiing. The most common mistake is ...

blog.sandwichtechskis.com

Notice:

Finally, the contribution of the metal’s loss factor is negligible since aluminum and titanium both have extremely low loss factors (1/15th that of the epoxy resin used throughout the ski). Titanium has especially poor damping and is used in guitar strings for this very reason. Put all of this together and we can see –despite popular belief– that while the metal laminates do decrease the initial amplitude, the vibrations will last for many more oscillations due to the decreased decay and therefore damping.

and neither do careful ski reviewers. Blister, for example, refer to 'suspension' - with suspension speed, suspension travel and suspension damping being entirely separate quantities.

 

[flbufl]

Some models of the Stockli StormRider are both very soft and quite damp skis. How do you explain that?

To me, damp and low rebound are very different. High rebound is archived by stiffer core + tall camber. Race skis are both damp and high rebound. I am sure a soft full rocker ski will be not damp and low rebound.

Right there, you did it again. A stiffer ski with a slower rebound speed does all that - even though it might dissipate less energy per vibration cycle than the softer ski. Damping only tells you how much energy is lost per vibration cycle.



Proving my point yet again. Notice that the ski designers I linked to above do not call that characteristic "damping"

Vibration Damping and Skis

“Vibration damping” has become a popular, often misused, term in many industries including skiing. The most common mistake is ...

blog.sandwichtechskis.com

Notice:



and neither do careful ski reviewers. Blister, for example, refer to 'suspension' - with suspension speed, suspension travel and suspension damping being entirely separate quantities.

 

[cantunamunch]

Some models of the Stockli StormRider are both very soft and quite damp skis. How do you explain that?

*shrug* They are soft and they are damp, meaning they have high internal losses. It's one of the completely appropriate uses of the word.

It is precisely because such skis exist that we shouldn't lump the Kendo sort in with them.

 

[Uncle-A]

I have not looked at every post but I thought the metal in the ski might add to the life of the ski. The OP said that he is 215 LBS and what are the pro's and con's of metal in the ski. So the pro is it should make the skis last longer.

 

[GregK]

Many skis(especially freestyle/freeride models) including Stockli use rubber layers(usually in the tip, tail and underfoot areas) to absorb impacts from jumps or variable terrain. The sidewall material and length into the tip/tails(full length sidewall vs semi cap) can also change the amount of vibrations felt in a ski. So skis can be softer flexing and “damp” feeling.

A basic article a few years ago from SkiEssentials about adding metal in skis to stiffen them and increase rigidity to reduce chatter as @cantunamunch mentioned. And with regards to skiers weight, a heavier skier will flex a skI more easily, so even a less advanced but larger skier may consider a stiffer ski with metal to compensate for their size.

SkiEssentials

www.skiessentials.com

 

[ted]

Some models of the Stockli StormRider are both very soft and quite damp skis. How do you explain that?

To me, damp and low rebound are very different. High rebound is archived by stiffer core + tall camber. Race skis are both damp and high rebound. I am sure a soft full rocker ski will be not damp and low rebound.

According to our Stockli rep, the adhesive they use has a large amount of rubber additive which is what makes their skis so damp.

 

[tromano]

To draw a MTB analogy, a skis stiffness is analogous to a Fork's spring rate, dampness is analogous to the oil and damper setup which controls how quickly it returns to full extension after absorbing a bump.

A softer flexing ski with good dampness can be a real joy since they feel like they smoothly absorb all sorts of terrain.

OTOH, a light, stiff under-damped ski transmits all sorts of vibrations to the boot which may feel unrefined and noisy.

I personally think that when people talk about chattering on edge, that is not a damping issue with the ski.

 

[Noodler]

Hmmm, I don't see dampness as something I've ever equated with the flex or "suspension" of the ski. For me it's always been about vibration absorption and this quality is seen/felt without needing to bend or flex the ski.

You can easily assess this on a ski just by holding it lightly in the middle and tapping the tip while it's close to your ear. Serious FIS level race skis respond with a "thud" while light hollowed core skis are incredibly "pingy". This almost always translates exactly as you would expect when they're put on snow.

 

[cantunamunch]

You can easily assess this on a ski just by holding it lightly in the middle and tapping the tip while it's close to your ear. Serious FIS level race skis respond with a "thud" while light hollowed core skis are incredibly "pingy". This almost always translates exactly as you would expect when they're put on snow.

You can do even better than 'ear' for the 0-100Hz range just by downloading one of the many NVH accelerometer apps to your phone and clamping it to the ski.