How to check whether you are correctly canted
and how to fix your boots if you aren’t

Signs and Symptoms

Before we start this discussion let me make something clear: Getting the alignment of your boots sorted out correctly will not transform a beginner into an expert skier. On the other hand, if your boots are not correctly canted you will suffer a significant handicap which will prevent you progressing easily or ever skiing as well as you could. Progress will be blocked and the root cause will not be recognised by the average ski instructor. Indeed, the better the instructor the more certain it is that they are among the fortunate few who have never suffered from serious misalignment of their boots.  Never having had to adapt to a bad boot by adopting an awkward stance, they will usually assume that other people’s stance peculiarities are simply the result of poor technique. They are mistaken to hold this view, but it is easy to see why they do.

What is meant by the “cant angle” of a ski-boot? It is simply the degree by which the cuff of the boot slopes outwards. Everyone’s lower leg slopes outwards and the boots are designed to match this angle. The key concept to grasp is that if the cant angle of the boot is incorrect for your legs you will have to adapt your stance in order to ski at all effectively. You will make this adaption without being aware of it.

The first thing for you to do is recognise what signs and symptoms will reflect errors in boot alignment. Most people who have serious stance problems on skis have under-canted boots. Their boots do not lean outwards enough to bring their knee into its natural position, vertically above the centre of their foot, when the ski is flat. Because the skis have to be flat on the snow to run in a straight line, these skiers are obliged to hold their knees inside the skis to achieve this. If they did not do this the skis would move apart, they would do the splits, and a heavy fall would result. Your balancing system, with all its proprioceptive feedback, is not stupid. So rather than simply slide to catastrophe you adapt by adopting a peculiar knees-inside-the-feet stance. This allows you to ski, but the unnatural stance is geometrically weak and prevents you ever edging your skis effectively or powerfully. Especially the inside ski.

So ask yourself a simple question. Do I ski in a knock knee position? Do I find myself concentrating on my outside ski and edging it by rolling that knee inwards? Do I look knock kneed on drag lifts? Any of these things suggest that your boots need more cant angle.

Under-canted boots are the norm and there is a night and day difference between skiing in correctly aligned boots and struggling with under-canting. Unless you check and correct your alignment you will never ski fluently. You may be completely unaware of the problem and only one in a million instructors or boot-fitters will recognise that this is a problem with the boots, let alone attempt to make the necessary changes to your equipment.

Why don’t instructors and other professional experts recognise this problem?

Some do. Ingemar Stenmark adjusted his canting constantly. Many of the best World Cup racers of today are equally committed, and some World Cup teams focus a lot of attention on the issue. But it is true to say that the average boot fitter does not recognise this is a problem with geometry, and the average ski instructor will simply try to teach skiers to adopt a ‘correct’ stance. Which will be impossible.

So, why the blindness? It is probably a consequence of the development of the plastic boot itself. Because children’s boots are traditionally manufactured without any built-in shaft cant (and beginner's boots too) the individuals who shine and progress are those who do not need much canting. Others, no matter how athletic they are, get left behind because they are under-canted. They switch to other sports. So the people who get to the top of the sport as racers, or top-level instructors, are those whose lower legs suit a very upright shaft on the boot. Little or no canting required in other words.

I believe that if you were to measure the canting requirement of most World Cup male skiers you would find that a very high proportion would be over-canted in the average ski-boot. The same will be true for many instructors who have progressed up through the levels of whatever system they work within. Incidentally, I have set myself up at about two degrees over-canted as an experiment. Carving was enhanced and early transfer to the inside ski was very easy. The feeling was amazing but it came with a downside. It was very difficult to sideslip or brake. This made it exhilarating on easy slopes but ultimately too frightening for me to want to ski in this configuration all day. It was a dangerous setup for everyday all-mountain skiing unless you have elite-level gifts and confidence.

Anyway, this is the heart of the problem I think. Top professionals undergo a natural selection because, within limits, over-canting produces higher performance than under-canting. Therefore over-canted children shine and advance quickly, sometimes all the way to elite levels. Then the manufacturers test boots on this group and conclude that little or no cuff-cant is the best configuration for good skiing. A completely circular argument as the testing has been done with a subset of skiers who are lucky enough to have this requirement and have become elite skiers because of this. But they are not a typical group.

Most expert skiers will be blissfully unaware that others might experience any problem with the modern boot. If they become instructors they will naturally assume that stance issues are caused by technical errors and that they can train everyone to ski in a ‘correct position’. When they fail to achieve this result they simply conclude that many people are ‘bad at skiing’. For their part, boot-fitters will assume that the manufacturers are correct. A brilliant boot-fitter (one of the best working in the Alps right now) told me that “the more upright the boot the better it performs”. A highly qualified and experienced man who has reached a wrong conclusion. But as he works with so many elite racers and free-riders this false analysis will seem to be confirmed.

In a perfect world all skiers would be brought into alignment by adjusting the shaft angle of their boot cuff. Many boots do allow the cuff angle to be adjusted by moving one or both hinge points. Alas, the range of adjustment this allows is far too small for most skiers to be fully corrected this way. Professionals can grind the sole of your boot to achieve alignment, or fit wedged shims under the bindings. The former is a costly and irreversible modification, and even fitting canting shims presents difficulties. In fact simply getting hold of them is challenging as suppliers are paranoid about liability claims. By all means try to get professional help from specialist suppliers and boot fitters. But I have to say that this may prove difficult. My own preference is for a DIY solution, and one that allows trial and error optimisation of your boots while on the snow

If you take the trouble to construct the  KPS Cant Gauge, it will allow you to measure the angular error that you suffer in your unmodified boots. You could use that measurement to have your boots ground or to specify the angle of  shims to have fitted underneath your bindings. But you may not be convinced by any of this yet. And probably want an immediate solution to confirm that it works for you. So, initially at least, a DIY approach is best. You can always get help to tidy things up later.

Obviously, if you need more cant angle from your boot cuff the first thing you should do is adjust the hinges if your boots allow this. It is easy to become confused when adjusting cuff hinges so bear in mind that you must watch what happens to the cuff itself. Your adjustment should move the inside lower edge of the cuff upwards or the outside lower edge downwards, or make both of these changes if both hinges are adjustable. Compare the first boot you adjust to the one you haven’t touched to check that the cuff has angled outwards. The way these adjusters move the cuff varies, and it can be all too easy to simply move the whole cuff up or down, or to adjust the angle in the wrong direction. So take care with this and then carry on as below:

There is a really quick and easy way of canting the cuff to bring your boots into correct adjustment for your legs. The series of pictures on the next page will show you how to do it. It’s simple. Make an adjustment and then check out the result on the snow. See how it feels and don’t forget to check how your alignment looks on the Pomas. Then add some more packing material to the inside of the cuff of the boot and try it again. Work on it until it feels really good. Then check with the KPS Gauge, if you have made one. If the gauge shows that you are still out of alignment add even more material. I am prepared to bet that it will feel even better. Keep adding material until you are certain that you have gone far enough. Then add a little more to make sure that you really have reached optimum alignment. You may be surprised at how much correction your boots need. You may not be symmetrical and one leg need more canting than the other. Don’t get lazy, don’t give up, keep working at it. When you complete the process the result really will be worth the effort.

What material should you use? Anything that works. Carpet or carpet underlay works and can be stuck on with duct tape. John uses a very neat self-adhesive high-density foam which comes in sheets and can be cut with scissors. You could even build up the cuff canting by using many layers of duct tape alone. I use the plastic spoilers that are used to increase the forward lean of most ski-boots. I collect them for this purpose. I build them up in layers attached to the boot with duct-tape. They also have the advantage that they can be easily and quickly inserted into the cuff of the boot on the slopes. They will stay in position for a couple of runs without the sticky tape and will give you instant feedback on the effect. Carpet or underlay can also be inserted on the fly in the same way. Instant alignment. Now look at the photos. Then just do it…

Whatever material you use it will gradually be squeezed upwards out of the boot. If duct-tape is used to retain the shimms it will stretch with time because of these loads. A long-term solution is to bolt the shims to the shells once the optimum thickness is established. Countersunk threaded screws will keep the internal surface smooth to avoid painful pressure points and, because there is a lot of vibration when skiing fast, use a nyloc nut to secure the screw on the outside of the boot.
And use a washer to make it look professional…

A classic stance adopted by the skier whose boots are not canted enough. Carving on the outside ski requires a conscious rolling of the knee.

The coach will tell this person to work harder at skiing in a less knock-kneed position. But in reality the stance will only improve when the boots themselves are modified.

I know, because that skier was me.

The Magic Poma

Perhaps the best indication of your canting needs is the way you ride the Poma drag lifts. For those outside Europe I should add that the drag-lifts we call Pomas are what you probably call “button-lifts”. For our purpose it doesn’t matter if the button lift has a flexible wire or solid metal upright. Get someone to ride behind you and take pictures of the way you are standing on your skis. Your individual problem with your boots should be absolutely obvious.

Incidentally, the awful T-bar problem of two skiers pushing their inside boots against each other stems from the same problem of under-canted boots. Two skiers who need to A-frame their stance to ride a flat ski cannot fit comfortably onto the same T-bar and will end up having a very difficult ride as they push against each other.

Another very telling symptom of canting problems is awkwardness when skating over a flat. Well aligned boots allow a skier to skate fluently and glide on one ski and then the other between the skating movements. An under-canted skier will topple from one ski to the other and will not be able to sustain a glide on one leg for more than a brief moment. Skating will be awkward.

This is a classic A-frame stance. Clearly this skier needs more cant angle in the ski boots. These particular boots are virtually upright and would suit very few skiers without serious modification.

And yet these boots are typical of those supplied to beginners!

This is an experienced skier riding the Poma in a rather knock-kneed stance.

This is the X-frame response to boots that need more cant angle.

Here is the same skier in the same rental boots after they have been canted by simply adding material inside the cuff. The KPS-gauge showed that about half the alignment error had been removed. And that’s how it looks.

Skiing became much easier for this novice after the modification.

Even the weather has improved!

Now with shims inserted into the inside edge of the boot cuffs.

Visibly improved.

(Note that the skier ahead is very A-framed)

More material added and the stance now looks very good. Skiing on and off piste became more relaxed and efficient.

 This skier has an artificial knee. Anyone can benefit from canting.

By Peter White

Just a quick note for those who realise that the knee, although far from simple, is fundamentally a hinge-joint. As such it isn’t actually free to move laterally unless your meniscus is very badly worn. When clamped into your skis wearing your ski boots the knees are flexed and can only move sideways (either inside the ski or to the outside) when the femur rotates at the hip joint. Throughout all the discussions on this website this subtlety is ignored and we will talk about the knee joint as if it could hinge inside or outside. This is how most people see things, how it feels to the owner of the knees, and perfectly expresses the balance and stance issues that I am trying to address. It is a simplification of a more complex reality, but it’s a useful one.