Skier weight and ski stability

[François Pugh]

General consensus on internet forums about skier weight seems to be that a lighter skier will find a ski more stable than a heavier skier skiing that same ski. For example, it has been suggested that a skier weighing 200 lbs would find ski X unstable at speed, but a 160 lb skier would not.

I've varied my weight from 140 to 180 lbs (it was for science ), and have found no such dependence of ski stability at speed on skier weight. Easier to bend into a tighter carve with more skier weight, yes. Less stable at speed with more skier weight, no. What I did notice is that when I am way past a skis' speed limit, it is easier to cope at 180 lbs than 140 lbs, but the ski still acts like a paint shaker on crack at that speed no matter my weight.

For those who have experienced the ski being more stable for lighter skier weight, can you please explain? What do you mean by stable, and what do you think causes the stability to be dependent on your weight?

 

[Brian Finch]

I’m with you! I’ll add that as a lighter skier, it is more important to have the flex of the boot/ski combo dialed in. Even the mount is more critical for a lighter folk.

2 thoughts: I’m always amazed to see folks larger than myself straight line or huck with no issues & then I feel like a squirrel on meth on the same terrain.

Second- again for the idk 10th season.... sigh I’m trying to go sub 180cm on my skis..... I always feel that shorties death rattle & I return to 186-196 lengths, yet that just seems silly at 5’9” / 140. I almost died last week when a lesser skier told me how it was a technical issue bc his 170s were iron solid at speed.

 

[Steve]

I've been wondering what to expect come ski season, particularly with my WC SL skis. My weight will have gone from about 177 to about 152. I'm not a racer but I never had any problems bending those stiff 165 skis. I wonder if it will be harder to bend them with 25lbs less weight. I'm not worried about stability at speed as much as short radius turns.

Honestly I'm not really worried because I still think that if my weight is utilized properly it will be plenty sufficient to bend the skis, but it's going to be interesting.

 

[Alba Adventures]

I've varied my weight from 140 to 180 lbs (it was for science )

....
@François Pugh
This line made me spit my coffee up!

 

[Tricia]

I honestly think it depends on the ski and the skier.
The other question is, how do you define stability?

From my personal experience -
When I was 20 lbs lighter (I gained 20 for science ) and was a self taught skier with little skill, I liked a longer, stiffer ski because it felt stable. I couldn't bend it, so I couldn't turn it but it gave me a platform to ride out of bad situations and stay upright.

After spending a lot of time learning to ski well (or at least better than I used to) I found that stability is relative to strength, skill, conditions and ski construction

 

[HDSkiing]

For those who have experienced the ski being more stable for lighter skier weight, can you please explain? What do you mean by stable, and what do you think causes the stability to be dependent on your weight?

Gosh so many variables. The one thing that your ski knows about you is your weight, so the one variable you can control before you get on snow is length, a longer ski in a given model line is going to have more mass, more surface area etc. there is probably some math formula out there that you can apply using weight X velocity to derive some type of relative force but I won’t even attempt to go farther because it’s also how one leverages the ski (starting at the boot).

A power skier (higher edge angles, feet farther from the midline think racing turn with wide stance leaving 2 trenches) vs a finesse skier (feet more or less stays under the shoulders, carved but probably not throughout turn resulting in more of a Z shape) get different results out of the ski and need different equipment, or at least it helps. A 140 pound power skier may bend the same ski more than a 225 pound finesse skier. To that power skier the same ski may feel less stable than the heavier finesse skier.

So when it comes to stability what does that mean? I dunno but I’ll give it a shot anyway

Few recreational skiers are likely to achieve the kind of speeds where stability is a huge issue, at least not before form and technique as what is often described as a stability problem is really a stance or form problem. That aside “ski chatter” is usually what is described and I suppose if we are talking about high speed, super-G turning runs the lighter skier might feel it later than the heavier one as their heavier weight would pressure the ski more making the tips bounce to a greater degree than the lighter skier?


Someone should do another science experiment

 

[mdf]

When I talk about skis being stable or not, I think of their response to highly irregular terrain (refrozen coral reef, variable-density crud, etc) at speed. Which is probably related to the amount of damping and whether the frequency response of the skis happens to work with or against the frequency response (active or passive) of my body. Since the spring constants don't change (for the same set of equipment) a change in load will make a big change in resonant frequency. But whether lower freq is better or worse is a mystery to be explored empirically.

For the other way of talking about stablily, namely "am I going to hook up unexpectedly and die while going fast in a straight line?", I think that is 70% sidecut and 30% flex.

 

[SSSdave]

Minus skier muscle motion exerted forces, the greater gravity weight on top of a ski, the more force it is going to exert down into snow. The more a ski is down into snow, the more its direction may be affected and the more friction resistance aka drag force it will have against the snow to slow it down. Thus one's speed is a balance between weight forces due to gravity (mass*gravity) against friction forces. If there is no resistance, then speed would be mgsin@ while with resistance minus (coefficient of friction)mgcos@. The reason a heavier weight atop a ski will end up faster down a slope is due to the differential between acceleration of different weights. A heavier object has more net force that is the difference between its mgsin@ and the drag force, that continually accelerates it more. Though the drag force is greater for the heavier weight, the differential net force quickly becomes greater.

A heavier skier's net forces overcome frictional forces more than a light skier thus they have more control as long as they dump more speed to maintain same speeds. Another common sense way to look at this is a ski with a 200 pound person down an irregular somewhat bumpy surface will move through the surface smoother than a 70 pound child that will be bounced around more with every little feature.

 

[KingGrump]

A power skier (higher edge angles, feet farther from the midline think racing turn with wide stance leaving 2 trenches) vs a finesse skier (feet more or less stays under the shoulders, carved but probably not throughout turn resulting in more of a Z shape)

Interesting definition of power and finesse skier.

 

[markojp]

F=MA... one's low mass might be well compensated for with more F and A a la Francois P, and that affects ski and boot preferences/needs (as if anything in the ski universe is an actual need) . It's also why folks in good shops ask so many questions. Penciling in a basic idea of the variables in the equation will help get us into the most suitable gear for a given narrative.

 

[Pequenita]

For those who have experienced the ski being more stable for lighter skier weight, can you please explain? What do you mean by stable, and what do you think causes the stability to be dependent on your weight?

Probably an oversimplification, but I've always thought of "stable for a lighter weight skier" as the skier's ability to balance on the ski because they are moving at a lower velocity due to mass and not hitting the speed limit.

 

[Eleeski]

"General consensus on internet forums about skier weight seems to be that a lighter skier will find a ski more stable than a heavier skier skiing that same ski."

I'm not sure that I agree with that. Having a ski that reacts the way you are comfortable with will allow your balance to be better - and hence more stable. Sounds more specific to matching a ski to a skier's skills than weight.

Eric

 

[dbostedo]

For the other way of talking about stablily, namely "am I going to hook up unexpectedly and die while going fast in a straight line?", I think that is 70% sidecut and 30% flex.

That's what I always thought "stable" meant... I.e. it's not going to do something unexpected - it won't "over-react" to either rough terrain, or skier inputs.

 

[Doug Briggs]

I think it is more a matter of overpowering the ski rather than inherent stability of the ski. You can put a 150# skier on a women's188 GS ski and they'll be able to ski it beautifully as will a 200# skier. The problem is that the 200# skier might overpower/overflex the ski because it's too soft longitudinally for him. Conversely, you could put a 150# skier on a men's 188 GS ski and they may find it very stable (too stable?), but unskiable since they can't bend it like the 200#er can.

 

[silverback]

Interesting definition of power and finesse skier.

https://www.realskiers.com/revelations/power-vs-finesse

 

[Tony S]

Interesting definition of power and finesse skier.

Yeah. I'm not down with it. Sounds like Jackson Hogen (as validated by gorilla guy farther down thread), notwithstanding his token reference to Anna Veith. (Though thanks for that thrill, Jackson.) Thinly veiled equating of size with skill. It's all Hogen can do not to use the phrase "the little lady" when talking about skis for women. Hello? Mikaela? Finesse skier. Too bad she can't get her feet out from under her. Sheesh.

 

[Tony S]

Probably an oversimplification, but I've always thought of "stable for a lighter weight skier" as the skier's ability to balance on the ski because they are moving at a lower velocity due to mass and not hitting the speed limit.

Yup. I'm light, therefore I'm slow.

It's true. Big guys definitely tend to beat me in the course when it's one that doesn't require actual turning or getting a ski to hold on ice.​

 

[Tony S]

I almost died last week when a lesser skier told me how it was a technical issue bc his 170s were iron solid at speed.

Yeah, well, there's speed and there's speed, right? Dunning Kruger. Just let it go, and keep paying your health insurance.

 

[KingGrump]

https://www.realskiers.com/revelations/power-vs-finesse

That is just a bad definition of power vs finesse. It's more like he is defining functional skiing vs stylized skiing (ski like Stein).

Yup. I'm light, therefore I'm slow.

Yeah, BS you're slow. I've skied with you.

 

[silverback]

That is just a bad definition of power vs finesse. It's more like he is defining functional skiing vs stylized skiing (ski like Stein).

Stein didn't ski with his skis under his shoulders. He was a power skier.