Height vs Weight...

[coachmdd]

Better than average skier but am an expert/elite coach of a non-winter sport and have a very strong command of basic sports science. Despite my knowledge I am struggling with the following question:

What is the distinction between one’s height vs weight as regards ski length?

Ice vs Powder, tight Eastern trail vs Western bowl aside, what sets optimal ski length?

For example length for a 6’6” 180 guy vs a 5’9” 240 guy both with similar skills. Better still, me at 6’2” 260 and my wife also 6’2” 160 but her with a 4” longer leg length (I am all torso)

Taller & heavier = longer ski in general
But asking about the relative contribution of each factor to ski length....

Any thoughts?

 

[surfsnowgirl]

I'm not tall at 5'6" but I weigh about 170 well distributed pounds. My skis range from 163-170cm. I tend to not like the Head Super Joys of the world. All but 3 pairs of my skis have metal in them but it's not required so long as the ski has some meat to it. I do know some folks who prefer lighter or beefier skis so I think personal preference can play alot into it as well.

 

[Bill Talbot]

Skis need to bend. Weight, aggressiveness and snow type are the key players. Height is a smaller factor in my opinion.

 

[Mike Thomas]

In general, I'd say height and leverage trump weight or mass... but that's a really general statement. Skiing, as a recreational pursuit, is about fun. Fun isn't dictated by algorithms. There is no 'right' or 'wrong' on preference with things like ski lengths. How you like to ski, what speeds you ski at, how much you use the ski to turn vs trying to turn the ski... it all matters more than absolutes based on physical size. Go have fun, try different things, see what works for you and don't worry about what anyone thinks.

 

[François Pugh]

Weight is the most significant factor, speed is the second most important factor and height it the third most important factor.

When you are turning, the turn forces vary inversely as the radius of the turn, vary directly with the mass and vary as the speed squared. The ski is the beam that carries the load. In soft snow, the more load (more M, more V, less R) the longer ski you need; try to ski too fast around a given turn with too short a ski for your weight and the load will cause the snow platform to break loose.

You may think speed trumps weight, as the turn forces vary with speed squared, but only linearly with mass, and it would except for one thing: the force that holds the ski to the snow results from gravity and varies directly with your weight, regardless of all other factors. Try to turn on ice and the ski needs pressure to cut into the ice. Ski too long a ski for your weight and the pressure on the edge will be insufficient.

Height allows you to work the ski by directing more force to the front and back of the ski, augmenting what the ski can do. Weight and height are equal factors in this aspect of ski manipulation.

 

[Analisa]

All just part of a very complicated formula. Trees? Bumps? Open bowls? I've also been skeptical of some threads here where a heavier beginner-intermediate gets a ton of responses like "you're a CLYDE. You need a CLYDE ski" - if you're still learning the basic coordination for skiing, you aren't putting the same force on the ski compared to when you're able to commit to a turn. I think body composition, proportions & strength matters too. I tend to like a longer ski than a lot of similarly sizes women I ski with, and I think it's because I have a gymnast background & did D1 cheer in college. Both sports require a lot of fast-twitch muscle strength, coordination, and favor short, muscular limbs.

Add on the fact that each ski is made differently, where a 180 Sky7 will ski super differently than a 180 Bonafide, it complicates the "algorithm" even more.

I agree with @Mike Thomas 's sentiment that the best place to start is a demo day. It'll take less time to play with construction and length for youself than it would to collect enough data points to "math" it out for the general population.

 

[geepers]

Here's a factoid - the ski sizing table at snowpro for Rossignol.

Notice it is stated up top: optimal ski length is determined by the following order: weight, ability, height and aggressiveness. The chart has only weight ranges for ski lengths. If you are on the border (e.g. 169-170lbs for many skis above) then you might want to try both sizes if one suits better.

Personally I always go for the shortest ski I can get away with. Less weight on the end of the leg and less effort to pivot means more vertical feet per day for the same level of exhaustion.

 

[Coach13]

I think everyone is covering this quite well. There are obviously a lot of different factors including the various ski choices. I’m 6’ 4” 250 or so and I like skis that are light, have a lot of energy and not overly damp. In my everyday skis (77-86mm waist) I like something in the 178-185 range. Any wider I go up to whatever is the longest size in the ski of choice.

 

[François Pugh]

I've noticed, that for me the 2nd longest length seems to be the ideal compromise.

The math isn't that complicated. Skis are made for skiers in a weight range for people from lightest person that ski is designed for to the heaviest skiers. Where you stand in regards to your weight relative to the range of weights other skiers who might use that ski determies where you should be with regards to the range of lengths the ski comes in. Go up by one length if you ski very fast, or make high-g turns on soft snow. Go down by one length if you ski slowly and don't demand high g forces from the ski on soft snow.

 

[Noodler]

Many variables play into the correct length selection. These include your height, weight (and how your weight is distributed), and even your BSL. There is no single formula that will work and recommendations are merely that. The type of ski also has a significant impact. I have narrow 165cm SL race skis that have a longer contact length and effective edge than my 190cm powder skis (when skied in 2D groomed conditions). Testing/demos are best, without those you have to go on your past experiences and/or ski review recommendations that may help.

 

[SSSdave]

At 135# 66" BMI 21/22 all 3 of my current skis fit squarely in the Rossignol chart for comparable ski type. Would suspect with a higher BMI than average, one has to pay more attention to weight and with lower BMI than average, one will need to consider somewhat longer ski lengths. Additionally all ski lengths for a specific model may use the same size of internal materials such that say the end of a metal layer is closer to ski ends with shorter lengths versus the longer lengths at the prime design length. That supposedly is not as often the situation in this era versus decades ago. However I don't tend to trust ski reviews on men's ski models as I 'm always at the short end so might get "stiffed". And why for instance when I may buy within a few weeks an 88mm at boot mid fat, will probably go with a well reviewed women's model.

 

[AngryAnalyst]

I think the people above have given you a lot of useful feedback. My attempt to summarize is that a lot of ski length is individual preference driven and there are probably a range of acceptable lengths for most skiers and uses. It’s ok to be unsure which of two lengths you should choose and different people have different rules of thumb.

My own two cents is that what sort of mass you have (muscle or fat) does influence things at the margin but mostly I agree with a lot of what’s already been said. Back when I was lighter and leaner I could really work big heavy skis. That is more tiring for me now. So partly it’s a fitness test.

 

[Noodler]

Another consideration is that skis "change" more than just the raw length measurement with the different available lengths for the ski model. That change could include their flex pattern, overall flex stiffness, sidecut, etc. This means that selecting a ski length can be more about what you need or want from the ski and the way you will ski it. This isn't as simple as it may initially seem.

 

[Wilhelmson]

I go with the longest ski I can turn quickly which is low 180s. I do fine on my old narrow 188 skis. When I demo newer crudbusters at 188 they're lots of fun on piste but I can tell they might get me into trouble in other situations.

 

[HardDaysNight]

Weight is the most significant factor, speed is the second most important factor and height it the third most important factor.

When you are turning, the turn forces vary inversely as the radius of the turn, vary directly with the mass and vary as the speed squared. The ski is the beam that carries the load. In soft snow, the more load (more M, more V, less R) the longer ski you need; try to ski too fast around a given turn with too short a ski for your weight and the load will cause the snow platform to break loose.

You may think speed trumps weight, as the turn forces vary with speed squared, but only linearly with mass, and it would except for one thing: the force that holds the ski to the snow results from gravity and varies directly with your weight, regardless of all other factors. Try to turn on ice and the ski needs pressure to cut into the ice. Ski too long a ski for your weight and the pressure on the edge will be insufficient.

Height allows you to work the ski by directing more force to the front and back of the ski, augmenting what the ski can do. Weight and height are equal factors in this aspect of ski manipulation.

The most significant factor is skill. The idea that mass or height is related to the ability to bend a ski ignores the fact that ski bend is related to edge angle and balance (which means pressure) on the outside ski and that is driven by how good a skier you are. It doesn’t take much pressure to bend a ski if you know how to use it. My 110lb, very skilled wife can bend a 188cm, 30m radius FIS GS ski that a 250lb male gaper couldn’t begin to stand up on.

 

[Tom K.]

I think everyone is covering this quite well. There are obviously a lot of different factors including the various ski choices. I’m 6’ 4” 250 or so and I like skis that are light, have a lot of energy and not overly damp. In my everyday skis (77-86mm waist) I like something in the 178-185 range. Any wider I go up to whatever is the longest size in the ski of choice.

Same here. I'm not as big as the OP (6'2" and 200) but in a narrower ski, I'm fine around 180. In a wider ski, I like longer, maybe for float, and definitely because I exert more fore and aft leverage on a ski than a 200 pounder who stands 5'6".

 

[coachmdd]

All interesting perspectives and good information. Too many variables to think that there would be one, “Golden Rule” so all feedback has been good to read.

This venue has been and remains a favorite to participate in and follow. Thank you all....

 

[skix]

Someone will need to explain to me why height is an important factor in choosing ski length. Weight and skill/aggressiveness make perfect sense since both influence the load upon the ski and hence the ability to bend the ski. Fast skiing and body weight generate forces that get ideally get vectored through our arch and bend the ski into a curve. But height being a factor implies we want to bend the ski with mechanical leverage and that having your head further from your boots helps in that. Is that true? Misstated?

Put another way ... why should a 3-foot tall 200-pounder not ski a stiff 180 cm for all-mountain use? Having height be more important than weight would put them on something much shorter. What's truly the most important factor here?

 

[cantunamunch]

. But height being a factor implies we want to bend the ski with mechanical leverage and that having your head further from your boots helps in that. Is that true? Misstated?

Not mis-stated. But you're not thinking through the angles involved. The shorter the person the greater the angle they have to shift through to balance while pressuring shovel or tail - and the greater the workout on their core, and the greater the demands on their brains' compensation mechanism. And even with forged steel core muscles and supercomputer brains, there are still limits from the boot and from the foot size - the skier has to stay within their base of support.

Your conceptual three footer simply couldn't swing their body weight through an arc great enough to pressure tip and tail while still staying within their base of support.
Could they ski a 180cm? Yes.
Would they be doing anything other than arc and park? NO.
It would be analogous to a 6' person attempting to ski a 360cm ski.

It IS a mis-statement to ask for 'most important factor'. What we're up against is limits.

Asking for a generic answer of which limit is most important is like asking for a generic answer to which wall of a house is most important.

 

[Noodler]

Not mis-stated. But you're not thinking through the angles involved. The shorter the person the greater the angle they have to shift through to balance while pressuring shovel or tail - and the greater the workout on their core, and the greater the demands on their brains' compensation mechanism. And even with forged steel core muscles and supercomputer brains, there are still limits from the boot and from the foot size - the skier has to stay within their base of support.

Your conceptual three footer simply couldn't swing their body weight through an arc great enough to pressure tip and tail while still staying within their base of support.
Could they ski a 180cm? Yes.
Would they be doing anything other than arc and park? NO.
It would be analogous to a 6' person attempting to ski a 360cm ski.

It IS a mis-statement to ask for 'most important factor'. What we're up against is limits.

Asking for a generic answer of which limit is most important is like asking for a generic answer to which wall of a house is most important.

Saved me a whole bunch of typing.

The simple one word answer is "physics". Where you carry your weight has a direct impact on how it will impact your boots and skis (as described above). Height is a simplistic way of noting that the CM is most likely in a different position than another person of different height. This all goes out the window when you have a skier that does not have a more typical body morphology. Most people know their height. Most people do not know where their body's CM is exactly situated.