Important realization about ski boot flex or stiffness

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Important realization about ski boot flex or stiffness

Postby h.harb » Thu Oct 27, 2011 8:16 pm

Hey Harald, Since the Vonn boot discussion has morphed to a discussion of the Dodge boot, I’m curious if you’d be willing to shed more light on the new Head boot and general boot stiffness.

This is my post:
...how many athletes, even at the WC level, can actually make use of such a stiff boot? As I understand, an improper setup can render even the best boot, completely useless to the most skilled athlete [point of the thread really I guess]. I know that I and many other very good skiers cannot [do not] spend 100% of their time on even a 150 flex boot... So, what is the relation between setup and boot stiffness, and where do you draw the line on a boot being too stiff for an athlete [thinking racing applications only for the time being]?

I know we have discussed this before and you are an advocate of a stiff boot for obvious reasons regarding pressuring the ski, etc; but I know you’re also an advocate of tailoring every aspect of the boot to the skier/athlete. With guys I know [22 FIS points] skiing a ZB Rossi [140 flex] it seems that it would take a special athlete to handle a 170 flex boot. Even at the elite level not all athletes are created equal.

So to summarize the above – when do you hit the point of diminishing returns in terms of boot stiffness?

HH response:
As you know I'm 150 pounds, I don't bend a boot and it's my philosophy not to, the best skiers don't want any boot bending or flexing. As far as your friend goes, , how does he know he wouldn't be faster in a stiffer boot? If the ankle position in other words, the dorsi flexion is right, in the boot, the flexing comes from the hips, knees and back. I have movement at the top of the boot, I don't stuff lots of spoilers behind my calf, and I adjust the booster so it's not over tight, and I leave the top buckle so I can move forward. That is how it works for me. I think the Dodge has some way to go before it's perfect, but for right now it's the best, super high performance boot, I know. I ski better off piste with a Dodge, it's just physics, it weighs about 1/2 of regular plug boots, less weight to move around if you get out of position and if you ski off piste aggressively; you are bound to have to manage your CG over your boots or vice vera.


Thanks for the quick response. That actually helps a LOT. The most intriguing part is regarding where flexing is coming from. Your philosophy is different from many – especially in this area of the country where the current buzz is all about softer boots. You’re getting your mobility in the boot from not having it clinched down overly tight on your leg at the top, not having spoilers, etc. This is similar to how I ski my boots as well, although I might try backing the top buckle off a turn or two… might be why I haven’t found the “magic” in a softer boot.

This allows you [us] to still ski with our ankles, but also have access to lever the front of the ski when we have to – at which point, the boot is going to flex no matter what because of the amount of force being transferred. I do appreciate my 130’s off-piste though, because I tend to over-lever the front of the ski mainly because I can get away with in here in NY. The softer flex makes my fore/aft less “touchy” in softer snow.

This is different from how others are getting ankle mobility – they are doing it with a softer boot – and I’m assuming are not leaving room for ankle mobility in the top of the boot – meaning they are probably clinching the boot down tight. They are aiming for ankle mobility, which is great, but they are sacrificing access to the front of the ski to do so. The other possibility is that dorsi flexion of their setups is not ideal, which is likely as well since it takes time and attention to fine-tune (at least it has for me).

Racers i know, have been pondering this topic for awhile. Their thinking is, dropping down to a Rossi ZA potentially (ordered a ZB and considering swapping for a ZA). I’ve been urging them to keep the ZB because I think going to a super soft boot is a mistake. The part of the reasoning I was missing was the point you just made about how you get your ankle mobility.

BTW – I totally understand why you like the Dodge boot. After handling them in the shop, it makes complete sense. The weight is incredible. That alone could make the boot a tremendous success – not even taking into consideration the lateral stiffness that comes from such a stiff material as carbon.


HH response to: Your philosophy is different from many –
I'm not sure if that's a compliment, but thank you. It should be because the success rate from "the many" is terrible. Our success rate is phenomenal. My need and understanding, and the same goes for those on the WC, for a stiff boot, is simple, you get a faster response to re-balancing with the stiffer the boot. This goes for everyone once you learn how to use it. It goes with technique as well. If you want to steer the ski and skid it until you have to jump on the edge set, get soft boots. With a supportive set up, you can adjust the pressure to the tip more progressively as well. It sound contradictory, but it's not, once you learn it. Think about it, if you are trying to get to the tip, before you get there the boot flexes, it moves away from you, you have to move farther forward, (while trying to tip it) and to do so you are working against the plastic. When I am at the front of the boot, I keep my hips moving forward until the tip bites, then I move off the pressure. This is a fraction of a second. If I am being thrown around I use the back and front of the boot to keep me centered. If my boot is soft, when I want to rebound off it, I can't get it, because the boot flexes away from me and absorbs my energy. It puts your recenter timing way off. It slows your reaction timing. The cycles of boot philosophy change, from stiff to soft, come and go over the years, just like opinions about wide stance to narrow stance change, for coaches. Most have no idea of why or what is actually happening. Coaches are terrible at boot setting, even at the world cup level. So they embrace philosophy or follow a trend instead of developing knowledge..


I believe as everyone here knows that soft boots are stupid and they just hold back your skiing development. They keep you at the same level. Look at the sport car comparison, more performance means, stiffer springs, lower Cg, stiffer shocks and bushings. THe German car makers have known this for years, even in their performance road cars. Try to corner in an American road car of the 60ies, 70ies and 80ies you were wobbling all over like in a boat, a joke. . Compare that to the first 911s or Jaguar XKEs. Or even a BMW 2002 or a 530.

The other part, soft boots put your body into a compromised position. They lower your hips, create more steering and give you lordosis ( curved lower back) You might even tear out an achilles tendon. Ha!
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Re: Important realization about ski boot flex or stiffness

Postby Ihamilton » Mon Nov 21, 2011 5:49 pm

I demo'd the Dodge boots the week before the tech camp and last week in the camp skied on my own new Dodge boots. Once I had them on I knew I could never go back to plastic. Prior to purchasing them ,I had several several discussions with my good friend and my boss. He has skied for 60 years, has taught skiing for 40 years and considers himself a PMTS cult member, in fact he recently was appointed as a contributor to PMTS. He told me not to get them that they were too stiff for the Whistler crude and as they were light I would get thrown around. Well, I skied Whistler crude today and it was as crudey as it ever gets. The snow was all cut up, there were ruts everywhere and all runs where completely bumped up. The visibility was no better than 30 per cent of what we had in Colorado last week. I was using Head SS and Wendell said I had the wrong skis. He had soft skis and boots. Today I found that I was knocked out of balance less, when I was knocked out of balance I wasn't as far out and my recovery of balance was so quick that I didn't miss turns, just kept the same arc. Wendell said I was 200 to 300 per cent smoother than he has never seen me ski in crude like this. With these boots I don't think I need to use my fat skis or my softer carvers. Might as well use the quicker more responsive skis because the boots absorb a lot and they are so quick. Whistler skiing is much easier in the Dodge boots.
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Re: Important realization about ski boot flex or stiffness

Postby serious » Tue Nov 22, 2011 4:13 pm

Ihamilton,

If the boots are stiff, then they cannot "absorb a lot", so I am not sure I follow that logic.

As for HH's preference for stiff boots with "a little room to move", I find this comment interesting: " I have movement at the top of the boot, I don't stuff lots of spoilers behind my calf, and I adjust the booster so it's not over tight, and I leave the top buckle so I can move forward."

The question I have then: is it better to have super stiff boots with a bit of room to move the leg, or is it better to have a "softer" boot (ideally with progressive flex) with no room to move in the cuff? The progressive flex ensures that after a bit of flex the stiffness increases exponentially (so you don't have that "bottomless flex" feeling). :shock:

My boot has a tight fit with a bit of flex and I admit that I like a tight fit around the cuff (but it is out of habit rather than anything else). But a tight cuff does give me nice feedback when I tip to the LTE at the top of the turn.
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Re: Important realization about ski boot flex or stiffness

Postby HighAngles » Wed Nov 23, 2011 6:29 am

I'm certainly no PMTS guru around here, but what I've been finding is that the difference in boots (and boot setup) equates to whether you're a "leg" skier or a "foot" skier. What I mean by that is a boot setup where the shells is kept tight around the lower leg seems to promote "leg" skiing whereas a boot setup that is very tight on the foot, but kept looser on the leg promotes "foot" skiing.

For years and years I was a "leg" skier using boots the touted progressive flex and were actually fairly soft flexing in the grand scheme of things. Since switching to a more precise stiff boot, but not overly tightening the top, I've "discovered" my feet again in skiing. I'm still getting used to it, but what I'm getting use to is actually being in better balance. I'm able to fine tune my balance much more easily using my feet rather than the larger gross motor movements of my leg.

Hopefully this all makes some sense to most skiers.
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Re: Important realization about ski boot flex or stiffness

Postby serious » Wed Nov 23, 2011 2:11 pm

HighAngles,

Hmm, I look at it exactly the opposite way. :D With a tight cuff and a bit of room in the foot (toe box actually), I feel like I initiate the movement with tipping to LTE, while the leg (and boot) follow. It is definitely what I am used to as opposed to what is the best thing to do, so it must be taken with a grain of salt!
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Re: Important realization about ski boot flex or stiffness

Postby HighAngles » Wed Nov 23, 2011 2:20 pm

Well I'm certainly not talking about "locking out" the ankle with a hard footbed. A tight fitting lower can still allow sufficient medial ankle movement to pressure the inside wall and make your foot tipping count (as long as you have a "proper" PMTS-approved footbed).

Serious - I'm trying to picture what you're dealing with when you have a loose fit for the foot while having the upper tight around your leg. It's hard for me to imagine how you would be able to actually effect real ski movement with only your feet if the boot is so tight around your shin that those foot movements can't really do anything on their own without creating associated leg movement.
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Re: Important realization about ski boot flex or stiffness

Postby serious » Thu Nov 24, 2011 2:17 pm

I believe my fit in the lower part of the boot is reasonably tight without killing circulation. I have custom foot beds and Intuition liners (heat moulded). It may not be perfect, but it is certainly not loose. But I definitely have no for/aft movement in the cuff. I have the Nordica Speedmachine 12 boot (120 flex) and I am 155lbs.
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Re: Important realization about ski boot flex or stiffness

Postby Matt » Mon Nov 28, 2011 1:21 am

Serious, if the cuff is tight you cannot rotate the shin in the cuff, and this means less tipping. The shin has to rotate because the knee cannot bend sideways.
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Re: Important realization about ski boot flex or stiffness

Postby Max_501 » Wed Dec 28, 2011 10:28 am

Old posts from HH:

One of the biggest controversies in skiing is still whether you should be using stiff, flexible or medium flex boots. Most of the PMTS coaches use a boot that is at least a 130 flex equivalent in a Doberman. Diana and I use a 150 flex, boots which is the Head RD, World Cup.

Over the last 10 years Diana has evolved from a better then average full-cert PSIA instructor level skier, to a top masters racer, as well as a competitive USSA racer, competing with the junior ranks.

During this period of time there has been a definite evolution in her ski boots. I use Diana as an example, because I was able to observe the transition and improvements of her skiing based on boots. I have always used stiff boots so there is a biases toward stiff ski boots. So it isn't fair to use me as an example for evaluating or comparing.

In the past years Diana has moved from Dolomite to Dalbello and now she's in a head RD 150 World Cup. Every time we made a boot change, the boots got stiffer and narrower, both laterally and fore/aft.

We know Diana has improved her performance. It is based partially on boots, mental attitude and also technique. Stiffer, tighter boots have made the difference for her mechanically, because she has a very loosely constructed foot, what we call a pronating foot.

As I said in the first post, the first day on snow is a great opportunity to understand and have insights about your skiing movements that you might not notice in the season. One of those movements is pulling the feet back and keeping the hips above or in front of my boots. The first day especially, on steep slopes,it is not unusual to have your skis run out in front of you. I think this is what skiers are talking about when they say they have difficulty staying forward. I understand what it's like to have my feet move forward when I don't want them to, this always seems to happen on the first day or the first few runs of the first day. So I make an adjustment to my fore/aft position, this adjustment involves physically using the hamstring muscles and pulling the feet under the body and keeping those hamstring muscles under a certain level of tension. If that tension disappears, the feet shoot forward. This is why I try to keep pressure at the back of the heel bone, as I pull my feet back that pressure increases.

Now let's connect pulling the feet back and holding the hips forward, to stiffness of boots. I do feel comfortable with my hips up over my boots or in other words, my feet back under my hips. I notice that using the front of the boot to give me an idea of where I'm standing over the skis, is a great help. Although I do not lean on the front of the boots, I do feel constant touching or pressure on my shins. If I were in a boot that was soft, every time I would pull my feet back, and try to stay in a forward position, with my seat over my feet, a soft boot would flex forward and away from me.

When you are trying to establish a consistent fore/aft position in a soft boot front, it is not a very reassuring feeling, as its hard to really know where you are standing when the boot cuff is moving.

Every time you want some resistance to establish your stance the boot flexes away. A continually flexing boot doesn't support stance over the center. If you do not go to the front of the boots while skiing you are back of a centered position. The boot should not only support where you want to stand, but be an indicator for your fore/aft balanced position. If your skiing involves a large range of fore/aft movement and the forward movement especially is quick or sudden, you will take a beating in a stiff boot. The question arises, is a better to continue to use a soft boot that does not support a centered stance or is it better to deal with a back stance with a soft boot to absorb your sudden movements? Will you ever find a comfortable attainable centered stance in a soft boot?

A soft boot will reinforce a back stance because it does not allow you to develop the confidence to move your hips up or your feet back, as support at the front from the ski boot isn?t there to hold your mass. A centered position is one where the hips are extended and the legs are extended. Skiers believe flexing is part of skiing as a position not a movement. Skiers should by extended through more of an arc then flexed. Flexing should only happen at the point of release. Most skiers don?t get out of the flexed position.

Back to the first day on skis, after skiing for an hour or so I began to notice I was not losing my balance to the rear chair position. While this was happening, I was analyzing the difference in my stance, the new one that allowed me to stay balanced. I definitely noticed that my hips were projecting into the front of my skis and boots as an extension of my legs. This may sound confusing, but it is part of how I describe how I stand on my skis.

The forward lean angle of my shin out of my boots, when they are touching the front of the boot, is the correct leg angle. What does go wrong from here, is that skiers are too flexed in the legs at the knees, which puts the hips low and in a rearward position. Our ability to apply pressure to the front of the skis and boots comes from the area around your seat or your hips. If it moves back or flexes down, your ability to apply pressure forward is totally gone.

If I lose the contact pressure over my boots, especially the contact to the front, and to the side of the boot, I know that the front of the ski isn?t biting the snow. So I am constantly looking for this pressure in and to the front side. Once I find it, and establish that?s where I want to stay, I don't have to think about getting forward. The sensations of skiing in fore/aft balance include an upright feeling on the skis, feet behind the hips and of the hips driving toward the boots.

The upper body also has a role in fore/aft balance. If you watch, especially the taller world cup racers, they are often bent forward at the waist near the end of the turn. This gives them more mass to work with over the feet, to lever or to pull the feet and skis back under the hips to begin the next arc.

Unfortunately fore/aft balance has limited movement awareness, identifiers. And moving forward in skiing is very specific to the sport, few other activities include this movement in daily life or other sports. I hope this post helps to bring awareness and motivate skiers to spend more time on learning what fore/aft balance really means.
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Re: Important realization about ski boot flex or stiffness

Postby Ihamilton » Wed Dec 28, 2011 12:37 pm

This is a great summary and one that I can really identify with. In November I got dodge boots which are very stiff. My old boots had a 120 flex so there is a huge difference. With my old boots I was more flexed and my seat more back. I have noticed that I am more upright but I will work on getting the feel of my shins touching the front of the boot without riding on them and see if I can feel more extension and an Improved hip/foot relative position. I couldn't have tried for this in my old boots. Some of my colleagues have gone the other way, softer boots, and I noticed more flex in their legs.
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Re: Important realization about ski boot flex or stiffness

Postby Numpty » Wed Feb 01, 2012 4:10 pm

The other possibility is that dorsi flexion of their setups is not ideal, which is likely as well since it takes time and attention to fine-tune (at least it has for me).


I am new to this site and I have found the discussion very interesting and saw the above mention of dorsiflexion. I have been trying to improve my fore/aft balance and have learned some things here that I hope too try this weekend. I struggle to stay forward and have been told I have a very large range of ankle motion, as in dorsiflexion and I have been looking at how that impacts my setup. I use a lange RX 120 boot which has a very 'upright' forward lean. I was told that perhaps a 'gas-pedal' under my toe would help by pre-loading my ankle. I tried removing the lifter from under my heal binding and found it harder to get over the front of the ski. It was not a conclusive test but it did not feel right, perhaps i needed to stick with it longer.
Any advice on how to 'fine tune' as mentioned above for large dorsiflexion?
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Re: Important realization about ski boot flex or stiffness

Postby HighAngles » Wed Feb 01, 2012 5:16 pm

Numpty - welcome to the PMTS forum. I'm sure you'll find some help in the area your currently concerned with, but if we're going to delve into skiing movements please provide us with your skiing background and your exposure to PMTS.

Anyhow, I think some still pics of you taken from the side (while clicked into your skis) would help. Make sure you're not leaning against the front or the back of the boot and if possible wear shorts. Video would also help.
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Re: Important realization about ski boot flex or stiffness

Postby JBurke » Wed Feb 15, 2012 10:51 pm

Harald,
Wouldn't it make sense for all skiers to buy very stiff boots?

For example, if I use rental ice hockey skates, my ankles collapse inward due to lack of support (and some would say I have weak ankles). However, wearing good quality CCM hockey skates, I don't even need to lace them all the way up and my ankles have no problem. It seems the same would apply to ski boots, in that you need a tight fit in the ankle and forefoot but still need the ability to flex your ankles.
Thanks,
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Re: Important realization about ski boot flex or stiffness

Postby Matt » Wed Feb 15, 2012 11:51 pm

J, Skates have lateral stiffness but little fore-aft stiffness. Ski boots should always have as much lateral stiffness as possible, but what is discussed here is flex , i.e. stiffnes in fore-aft direction. Quite different from skates.
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