Choosing the right skis & bindings

[Mike]

This was previously posted:

Choosing a pair of skis to match your ability and physique -

Ski Ability Level
First determine your ability level: Recreational; Advanced or Expert

Your Ski Type
The next step is to determine your skiing style. It is important to choose the right skis for your style in order to get the most enjoyment and progression out of them. Below, the basic factors for each ski type are outlined:

Piste
As the name suggests these skis are designed to perform on the piste. That's not to say you couldn't have some fun after a fresh snowfall, but really the skis are set up to help you progress your skiing towards perfect carved turns.

Piste Prestige
This fast carving skis will let you dominate the fast lane or sit back and enjoy the view. Usually based on race ski construction but tuned to be slightly less demanding and more versatile.

Freestyle
Freestyle is the ‘new-school’ style that is currently the coolest thing in skiing. The skis are all twin tip for easy spins and fakie (backwards) moves. The freestyle skis also work well in deep snow due to their increased surface area.

Freeride
The all-terrain ski, perfect for people who want to go everywhere that snow can take them. Off-piste is the main focus; the increased surface area gives greater floatation in deep snow. The side-cuts are deep for stable carving and quick responses when skiing on the piste.

Big Mountain
For those who want to search out the most challenging off piste terrain. Big mountain skis have a huge surface area that provides excellent flotation in all conditions, from fresh powder to crud and are a real advantage when learning to ski deep snow.

Skier Cross
These skis are based on race skis, generally using a Giant Slalom ski construction and length with a deeper, more radical sidecut and shape. This results in a high performance ski that is incredibly manoeuvrable with excellent stability and edge grip on hard pack and icy snow. These skis also perform off piste due to their large surface area.

Race
For the skier that likes to ski hard and fast with confidence and control and demands absolute performance from their skis. Race skis provide excellent edge grip for skiing at speed but require energy and constant technical input from the skiers. Designed for skiing on-piste, they are for expert skiers and racers

Choosing The Right Skis
Through experience, one thing I have learned is that whether you are a beginner in the ski world or a professional, you need to have the right skis. Knowing what to look for will help you make the right choice. Length, shape and stiffness are all factors that need to be considered when choosing skis. Most ski rental places will gladly advise you on what type of ski you need, but they may be busy and not volunteer the information unless you ask. Here are some tips on what to look for:

Length is the first thing we will look at. Shorter skis are easier to carry because, of course, they are lighter and shorter skis can generally turn quicker but they are not as user-friendly at high speeds than longer skis. It is widely recommended that you pick a ski that is anywhere from chin level to head high depending on your level of skiing ability. Advanced skiers use skis equal to their height or within three inches below their height. Beginners or intermediate skiers use skis that reach the chin or nose.

Shape is also a factor to think about when choosing a ski. For better response on shorter, tighter turns, choose a ski with a deep side-cut (narrower at the waist or middle of the ski). Beginners should pick a ski with a shallower side-cut (wider at the waist) that will provide more stability and a smoother ride.

Ski stiffness determines a little of how much control the skier has when skiing. Skis come in several levels of stiffness. A stiffer ski is not as ideal for beginners as a softer ski because they require a greater amount of control. You can test stiffness by trying to flex the ski and if you try several, you will soon see the difference in stiffness.

So you see that length, shape and stiffness all affect how we ski.

Confused by all the new skis out there …
Today there is a tremendous array of ski to pick from. Many, many good skis and a few great skis. many skiers ask the age old question, what is the difference between a beginner ski , an intermediate ski, an advance or experts ski.

Outwardly, on the surface to most folks it may appear that there are no differences and combine with the seemingly overwhelming selection out there. So, how does one pick a ski?

First of all, there differences between a beginner ski and the intermediates and advance skiers’ski is the construction, internally and externally.

But before we get into that, we need to consider the three basic recreational functional categories: carve, all terrain and powder. The construction and side-cut is quite different for each.

Let's clarify some mysteries here, numerically speaking, the sidecut is the curve of the side of the ski. There are three numbers associated with this. These are the metric measurements of the widths of the ski at the top or shovel, the waist and the tail of the ski. These numbers dictate the turning radius of the ski. Typical shovel measurements would be just over a 100mm to the high 110mm's (unless you look at pure powder skis, where in the case of the Salomon Pocket Rocket, the shovel is 122mm and the waist is 90mm).

You will see waist measurements from the mid 60's to about 70mm for carve skis. Waists from 70-80mm may be consider all mountain or all terrain skis, which would provide more floatation in powder than a carve ski. Then skis with a waist of 80 to over 100mm may be consider as a ski for powder, since the greater surface will allow the skier to ride higher to the surface of the snow. You will find that the wider waist ski will have a longer turning radius (higher effort for tight turns).

The tail width measurements are typically about 10mm less than the shovel. From say just under 100mm to a few mm over a 100mm.

Next is the stiffness of each section, shovel waist (sweet spot) and the tail. How these variables are applied will determine how easily the ski initiates a turn, how forgiving it is and how stable it is at speeds, how comfortable it is over crud, grip on ice and etc.

General rule of thumb for length, mid-ear to top of head, remember, longer skis may not always be right for you and almost always means more work.

To obtain a more specific ski length, please refer to the chart underneath. It is also necessary to adjust the length for your ability level and aggressiveness. Please use this chart as a guideline only:

Weight under 49kg use 140cm skis
Weight 50 -56kg use 145cm skis
Weight 57-62kg use 150cm skis
Weight 63-68kg use 155cm skis
Weight 69-75kg use 160cm skis
Weight 76-81kg use 165cm skis

The given length from the chart will provide your ideal ski length for Piste skis. However, as our visual aid of the skier suggests, different styles of skiing will also affect the length of your skis. Below are outlines of how to adapt your ski length accordingly for other ski types:

• For Freeride skis add between 5 and 10cm in length for better flotation and stability in powder.
• For Big Mountain skis add between 5 and 20cm, depending on how much off piste you ski and for improved flotation and stability in the steep and deep.
• For skis designed to be skied in shorter lengths (Salomon Streetracer, Atomic Metron and any slalom ski), you should reduce the measurement by 10 to 15cm, in accordance with the specific manufacturer’s guidelines.
• For Freestyle and Skiercross skis, use the same length as for Piste skis.


Women have a different body build where their center of mass is lower than with men. This causes women to have the tendency to lean back more. Women also weigh less than men, which means that their Skis need to be more flexible to gain the same flex in turns as men do. If you are a woman, it is wise to buy Skis specifically designed for women. They are lighter in weight, more flexible and the Ski Bindings are set more to the front to accommodate the lower centre of mass

[Mike]

Having chosen (and tried out) your choice of skis, what about the ski binding?

Just as boots affect how your skis respond, bindings are also elemental to skiing control and safety. Skis, boots and bindings work in unison, and a good pair of bindings can even help you ski better. They absorb shock, filter out vibration and reduce fatigue.

Bindings consist of both a toe piece and a heel piece; ski brakes are prongs attached to the bindings, under the boots and anti-friction devices (AFDs) are metal or Teflon pads mounted on the ski under the forefeet.

In today's market there are many bindings to select from. The first step in determining the best binding for you is to answer the following questions:
• What type of skier are you — beginner, intermediate, or expert?
• Are you aggressive on the slopes? Will you try just about anything? Or are you more cautious?
• What are your height and weight?
• What is your budget?

Skiing Ability, Weight and DIN
Bindings are made with specific DIN ranges or tension release settings — the amount of force needed for the boots to be released. DIN (Deutsche Industrie Normen) that sets standards for binding release tensions, but the term is used to refer to the release settings as well.

The lower the DIN setting, the more easily the binding releases while a higher DIN setting is harder to get out of. Beginners fall frequently, so a lower release tension is necessary for them to avoid injury. Experts, on the other hand, need a higher DIN setting so that the vibrations and jarring of a fast downhill run don't release the boots and cause a crash. Body weight also affects your DIN setting. A heavier skier puts more force on bindings during a fall, and requires a higher DIN, whereas a lighter person should go with a lower setting. In general, DIN settings are as follows:
Beginner — 3 to 6
Intermediate — 5 to 9
Advanced — 6 to 12
Racer — up to 24

Front and rear bindings tend to be set on the same number and both skis are usually set the same. Injuries may affect these.

As a guideline the following chart can be used:

ADULT DIN CHART (UNDER 50)
Weight 35Kg use DIN setting 3
Weight 40Kg use DIN setting 3.5
Weight 45Kg use DIN setting 4
Weight 50Kg use DIN setting 4.5
Weight 60Kg use DIN setting 5
Weight 65Kg use DIN setting 5.5
Weight 70Kg use DIN setting 6
Weight 80Kg use DIN setting 7

Release is as important as the holding function of a binding. When screaming down a mountain, you don't want your boot to slip out of the binding, but you don't want your boot to stay attached in a crash, either. A binding with a DIN of up to 24 is great for racing, but it could cause injury to a casual skier if it doesn't release during a fall. Buy a binding that's designed for your ability. If it's set properly, you can be confident it will release properly.

The binding itself makes a big difference in ski performance, but so does how and where it's mounted on the ski. Generally, the farther back the binding is mounted, the stiffer the ski response. Most ski manufacturers recommend a mounting position, and a qualified ski shop will mount them correctly. Because women have a different centre of gravity than men, their bindings are often mounted slightly forward of centre. This allows for less fatigue and better control when skiing.

There is no medal for being macho! :D

Nowadays, majority of the skis offered by major brands are designed to incorporate (and sold with) integrated bindings and interfaces.
Integrated systems generally provide a more natural flex, better power transmission, and a larger sweet spot, they also add more distance between the boot and the ski.
In theory, easier flex means even, balanced edge pressure to the snow surface. Leading to better control through precise pressure distribution over the length of the edge, and hence better performance. When the ski is bent into more or less a true arc, the upper of the ski is compressed. The distance between the toe piece and the heel piece of the binding decreases naturally. However, when the ski is in use with a boot bound in, the middle of the ski cannot be bent naturally as the boot length does not change.

[Mike]

And for ski poles

Ski pole length is the most important factor to consider, and it is important to have ski poles with the length suitable to you. These days, poles are made of old-fashioned aluminum and modern-day composites like graphite. Some have useful features such as length adjustability and releasable straps to protect your wrists and thumbs.

• Ski Poles that are too short will make you bend forward too much, resulting to an overly flexed stance. This will further lead to an unnatural, reaching pole swing if you slightly flex and try to have a solid pole plant on the snow ski surface. Very long ski poles will force you to an overly tall position, and they can also affect your smooth pole swing manoeuvres.

• To find the ski pole with the ski pole length suitable for you, do the following steps:
1. Turn the ski pole upside down, with the ski pole grip touching the ground and the basket resting on the top of your fist.
2. Put your body in a skiing stance. Place the grip in front of your feet. You hands must also be in a skiing position.
3. At this point, your forearm and upper arm should be positioned at a 90 degree angle. When this is the case, the ski pole has the correct ski pole length for you. If not, try another one.

[teahorse]

so Mike, I am 200lb and 167cm, intermediate level skier, what is your recommendation regarding ski length and width? Many thanks!
I am considering getting a secondhand pair of atomic metron B5, 152cm

[skier]

so Mike, I am 200lb and 167cm, intermediate level skier, what is your recommendation regarding ski length and width? Many thanks!
I am considering getting a second pair of atomic metron B5, 152cm

I think you should get a little longer length skis then 152 cm (say 160 cm +) and a bit softer than Atomic B5.

I recommend you go for skis around 124/76/107, and not too much fatter.

But best of all, you should try out skis (rental demo skis) before your buy any skis since you may not have the experience just reading the reviews.

[eLeung]

But best of all, you should try out skis (rental demo skis) before your buy any skis since you may not have the experience just reading the reviews.

Totally agree :)

[Mike]

I think you should get a little longer length skis then 152 cm (say 160 cm +) and a bit softer than Atomic B5.

I recommend you go for skis around 124/76/107, and not too much fatter.

But best of all, you should try out skis (rental demo skis) before your buy any skis since you may not have the experience just reading the reviews.

As "Skier" said, you should try around 160 in length.

[teahorse]

Thank you guys! I will be going to Niseko 11jan for one week of skiing.
Just got my boots sorted out ( my right foot is almost 1cm longer, and a lot broader) at Sheung Wan. Now they feel comfortably tight, rather than painfully tight. :)

[sirius]

Thank you guys! I will be going to Niseko 11jan for one week of skiing.
Just got my boots sorted out ( my right foot is almost 1cm longer, and a lot broader) at Sheung Wan. Now they feel comfortably tight, rather than painfully tight. :)

if you don't mind, how much did you pay?

[teahorse]

if you don't mind, how much did you pay?
My first pair of boots / ski / poles costed me HK$3000, bought in Seoul.
It turned out that the boot was 3 size ( 29 ) too large for my feet, the ski was too long and soft ( a very basic atomic ), the only equipment I could still use are the poles...

Now I wear a 25.5 boots, with proper fitting and stretched according to my foot's shape and sizes. Look forward to skiing next month.

Cost : ~ 5K. Boot fitting charges included.
Sheungwan is quite costly, but where else can you find boot fitting service???

[teahorse]

As "Skier" said, you should try around 160 in length.
Dear Mike,

Do you know of any joint in Niseko where I can rent and try out different skis before even considering buying?

[Mike]

Dear Mike,

Do you know of any joint in Niseko where I can rent and try out different skis before even considering buying?

Sorry, I do not know any, I think "Freeskier" is in a better position to help you on this.

[Mike]

I think you should get a little longer length skis then 152 cm (say 160 cm +) and a bit softer than Atomic B5.

I recommend you go for skis around 124/76/107, and not too much fatter.

But best of all, you should try out skis (rental demo skis) before your buy any skis since you may not have the experience just reading the reviews.

76mm waist to me is mid-fat, they are fine.

My Volkl is 67mm in waist and Stockli is only 63mm ;)

We have been saying that one should try the skis before buying, but it is so tempting to buy based on reviews (especially when they are offered with a decent discount). :D

[sirius]

My first pair of boots / ski / poles costed me HK$3000, bought in Seoul.
It turned out that the boot was 3 size ( 29 ) too large for my feet, the ski was too long and soft ( a very basic atomic ), the only equipment I could still use are the poles...

Now I wear a 25.5 boots, with proper fitting and stretched according to my foot's shape and sizes. Look forward to skiing next month.

Cost : ~ 5K. Boot fitting charges included.
Sheungwan is quite costly, but where else can you find boot fitting service???

wa... so expensive.... better than rob... :eek:

[skier]

76mm waist to me is mid-fat, they are fine.

My Volkl is 67mm in waist and Stockli is only 63mm ;)

We have been saying that one should try the skis before buying, but it is so tempting to buy based on reviews (especially when they are offered with a decent discount). :D


Actually 76mm and 67mm is only 9mm in difference -- which is less than 0.5cm wider on each side of ones boot, and that should not be too noticeable when skied.

But the float should be better (together with the wider tips) in powder. Will let you know how my new Blizzard magnum 7.6 IQ with 124/76/107 dimensions work out.

[Mike]

Actually 76mm and 67mm is only 9mm in difference -- which is less than 0.5cm wider on each side of ones boot, and that should not be too noticeable when skied.

But the float should be better (together with the wider tips) in powder.

Using the "ski surface calculator" available on-line, I calculated the ski surface area of my Vokl Supersport and Stockli Laser SC, the surface area for the Volkl is 1626 sq.cm. and that for the Stockli is 1498 sq.cm. (my Volkl is 4cm longer than the Stockli)

[skier]

Using the "ski surface calculator" available on-line, I calculated the ski surface area of my Vokl Supersport and Stockli Laser SC, the surface area for the Volkl is 1626 sq.cm. and that for the Stockli is 1498 sq.cm. (my Volkl is 4cm longer than the Stockli)


Hmm....That's odd

My ski: 170 cm and 124/76/107 calulates out to be only 1520 sq. cm which is 100 sq. cm less than your Volkl.

What is your Volkl length and spec.?

[Mike]

My ski: 170 cm and 124/76/107 calulates out to be only 1520 sq. cm which is 100 sq. cm less than your Volkl.

What is your Volkl length and spec.?

It is 112 / 67 / 97 and it is 161cm in length.

It is odd, isn't it?

[skier]

It is 112 / 67 / 97 and it is 161cm in length.

It is odd, isn't it?


Yours should be 1283 sq. cm

[Mike]

Yours should be 1283 sq. cm

Oh, I have input the vital statistics in the wrong order.

[Mike]

hi Mike and Skier

i read some of yours posts and learning ski in WOW
i want to buy a pair of ski boot and will you advice me how much i should spend on my first pair.

boot fitting service is it necessary for beginer??
beside what is the address in Sheungwan providing boot fitting service??

thx very much

knighttmfox, I have moved your question to another thread on how to choose ski boots -

http://www.hkssa.net/showthread.php?t=9518

Your questions will be followed up under that thread.

[Mike]

Traditionally, the width (the waist) of the skis is less than 70mm, but in recent years, the width has become wider and wider (in some extreme cases, over 100mm), so what diference does it make?

Historically, powder skiing was not popular at all until Atomic brought out the fat skis some 20 years ago, and then came fat skis with a 40mm side-cut.

The thing with 'race skis' (and traditional skis) is physics. SL and GS skis are torsionally rigid - they do not twist. They have an even flex tip to tail and thus a smooth arc. They do NOT skid easily. This means that when you ski in the snow on edge angles of 75-85 degrees, they generate a huge g-force that rips up through your stacked skeleton and threatens to crush you. Of course you do not crush easily - you redirect this force into the new turn with no deceleration whatsoever.

Now, the closer these massive g's are to the center of your skeleton - the middle of your foot and tibia -the ankle- the easier it is to deal with them. The wider a ski is the more this suspension is out of alignment and the harder it is to ski at ski race levels of speed and g's. This is why there are no World Cup racers on FATS. Also, that's why race skis have about 65-69mm waists - whatever the FIS rules are.

Fats are useful but are a compromise for bad technique and those who skid, or in the thick thigh deep powder where float is needed.

[Yogi]

Is fat skis more easy or more difficult to carve (on piste) than skis with narrow waist? :think: Any experience to share?

[skier]

Is fat skis more easy or more difficult to carve (on piste) than skis with narrow waist? :think: Any experience to share?



Since all racing skis are not fat skis, that already tells you the answer - fat skis are for better flotation in powdery snow.

[Mike]

Having chosen (and tried out) your choice of skis, what about the ski binding?

Skiing Ability, Weight and DIN
Bindings are made with specific DIN ranges or tension release settings — the amount of force needed for the boots to be released. DIN (Deutsche Industrie Normen) that sets standards for binding release tensions, but the term is used to refer to the release settings as well.

In general, DIN settings are as follows:
Beginner — 3 to 6
Intermediate — 5 to 9
Advanced — 6 to 12
Racer — up to 24

As a guideline the following chart can be used:
ADULT DIN CHART (UNDER 50)
Weight 35Kg use DIN setting 3
Weight 40Kg use DIN setting 3.5
Weight 45Kg use DIN setting 4
Weight 50Kg use DIN setting 4.5
Weight 60Kg use DIN setting 5
Weight 65Kg use DIN setting 5.5
Weight 70Kg use DIN setting 6
Weight 80Kg use DIN setting 7


Here is a website which will quickly work out the correct DIN setting for you:
http://www.dinsetting.com/

[Mike]

Regarding the length of the skis, the following advice is from a very well regarded ski store.

“Going to the next longer size will add stability and smooth out the ride a little, at the cost of low-speed maneuverability. When you drop a size, the skis feel more responsive, but less stable at high speed. The bottom line is that you should ski the shortest size that you’re comfortable skiing fast on. Anything longer is just unnecessary extra effort, and using skis that are too big can force skiers to develop awkward technique to compensate. The skis should be short enough to turn easily at the speeds you ski at, and long enough to feel stable when you open it up.

One size larger would probably touch your nose but I doubt if you'd notice the difference in stability. If you're a little unstable because you're going too fast that just normal stuff but the better your balance and the better your skills the more stable you will be. Enjoy your new skis and if you outgrow them in a year or two just celebrate your improving ability."

[Mike]

When choosing skis, note that mainly there are two different type of ski base - sintered & extruded.

Most ski bases are made from a polyethylene material called P-Tex. (P-tex is a tradename for the polyethylene base material used on skis and snowboards. It was originally produced and supplied to ski manufacturers by Inter Montana Sport (IMS) of Switzerland, and, although other companies now produce polyethylene base material under different trade names, just about everyone in the ski industry still refers to it as p-tex out of habit.) These bases are either "sintered" or "extruded" type.

Extruded p-tex is a low molecular weight polyethylene that is manufactured by heating it to 350 degrees F. and pressure feeding it through a die to the desired shape and thickness. It is used as a base material for many recreational skis and snowboards. Extruded bases (especially on snowboards) are more likely to exhibit warpage (being convex or concave) which can negatively affect the ride.

Sintered p-tex is made by packing ultra high molecular weight polyethylene powder into a cake that is heated and compressed (sintered) to form a log or billet. A lathe is then used to shave off a thin layer to the desired thickness.

If you are looking for high performance, buy a pair of skis with a sintered base. The advantages of sintered over extruded p-tex are 20-25% higher abrasion and impact resistance, a very low coefficient of friction, and the ability to absorb over 3 times more wax. Accordingly, sintered p-tex is found on the bases of most high performance skis and snowboards.

There is however, another type of ski base that is better than the sintered P-Tex base, that is a "graphite" base or known as "Electra" base. Electra base is a sintered p-tex to which 15% carbon black and graphite have been added to increase electrical and thermal conductivity. The frictional heat that develops (especially at higher speeds) is dissipated better along the entire ski or snowboard base due to this thermal conductivity. It helps reduce the water film that can otherwise build up and create suction and drag. The improved electrical conductivity helps reduce static electricity build-up that attracts and holds dirt and pollutants on the base, also creating more drag. The addition of graphite has been shown in tests to reduce friction and increase glide on snow by 20% or more over clear (non-graphite) p-tex bases in cold dry snow (under -13°F or -25°C), and by 15 to 20% more in warmer snow (over 23°F or -5°C) when humidity is 40% or above.
The drawback of Electra bases, however, is less water repellancy and both impact and abrasion resistance than that offered by clear sintered p-tex.

[Mike]

2012 skis buyer's guide: http://global.skipass.com/gearguide/ski/

[knighttmfox]

can anyone tell me how to measure the sidecut????
thx very much

[Mike]

can anyone tell me how to measure the sidecut????
thx very much

http://www.omerandbobs.com/info_center/winter_faq/winterfaqmain.html#generalstuff1

http://www.math.utah.edu/~eyre/rsbfaq/physics.html

Please note that sidecut radius and turn radius are different things, and actually kind of inversely proportional.
Also, despite the way the calculation is described in the above link, different ski companies sometimes use different methods to either measure the variables in the calculations, or may even use different formulas.

[Mike]

Now and then you read in the ski review that certain skis have a stiff tail, so what is the difference between stiff and soft tail?

In general, a stiffer tail lets you get the force to the back of the ski quickly when desired, it will give you more kick and stability finishing a turn and more directional stability at higher speeds, but it'll be less forgiving. Racers have stiff tails skis because they want to accelerate out of their turns, but most people generally turn to slow down. A stiff tail will also makes you bog down in deep snow if the slope isn't steep enough to keep your speed up.

In moguls, skis are designed to jump tend to have balanced flex, with softer, springy tips and tails to launch and land, but firmer mid-sections for stability (Dynastar's Big Trouble is a classic example).

Rocker skis tend to have stiffer tails.

A softer tail will wash out. This will help with speed control in steeper terrain, as you can skid the tail to drop speed.

[Mike]

For ski bindings, how do you know that the binding is doing what they say it does?
What do you value in a ski binding? Is it retention, is it joint/bone safety, is it durability, is it value, is it ski performance characteristics?

There are different types of skiers out there, some value retention over everything else, some want maximum safety, and many who just want something that "works" and is durable. It is important to pick a pair of binding that match their needs and desire. You certainly don't want to put an older or beginner or intermediate skier on "retention oriented" bindings and the opposite is true for an aggressive skier or racer.

Every binding manufacturer makes a product that will pass the mechanical function test. It doesn't mean that any of the bindings in the market are particularly "good" or "bad", just pick the one that fits your personal release/retention preferences.

There are lots of jargon - elastic travel, lateral stiffness, mounting base width, ramp angle and effect on ski flex. For most recreational skiers, there will be little noticable difference. The one factor that is important to skiers of all levels is stand height. The current conventional thinking is that more height is preferable for carving and less stand height is better for off-piste skiing.

Unfortunately, there appeared a current trend of manufacturers making bindings that are cheaper to produce at the expense of safety/performance features and long term durability. Stay away from these.

[Mike]

What is the line on the skis, is it the centre line or what?

You will notice there is a line marked on your skis either on the sidewall or on the surface. That line is not the centre line of the skis nor the centre of balance. This line is the Ski Boot Centre Line which is a combination of balance, cord centre and more importantly in carving skis, the centre of the side cut curve. It is positioned such that small changes in body weight will weight tip, tail or the centre of the ski and give control where needed.

The position of this line is a recommendation which the ski manufacturer considers is the optimum position, some skiers will have their own preference depending on their style, technique and/or use. However, each manufacturer has his own way to work out this "optimum" position.

[Mike]

Flatness of ski base - how "flat" is enough?

Refer to http://www.hkssa.net/showthread.php?p=79122#post79122