Ski boot flex with expert boot fitter Brent Amsbury

Ski boots come in a variety of different flexes, like this one here is a 150. It's definitely on the stiffer end of the range. So why do boots come in this different flex range? Why are they not just the one same level of stiffness? Well, on today's podcast, I've brought along expert boot fitter and probably the most knowledgeable guy on the planet I know about ski boots, and that is Brant Armsbury. He's been on the show before, and there are some great episodes you should check out in the Big Picture Skiing podcast archives. On many other different topics, but today we're here to talk about boot flex, and our real goal here is to inform you to make a better decision with your next pair of ski boots. If we can give you a little bit more insight and information into what parameters make a ski boot more stiff, make it more flexible, all these things like plastics, the way the cuff sort of interacts with the lower, if there are cuts in certain sections, bolts in the back, all that sort of stuff, you're going to find out more and be able to make a better decision to work with your boot fitter and find that ideal ski boot fit for yourself. Finding that elusive perfect ski boot is a difficult process, and there are so many things you've got to get right: the length, the volume, the width, but the flex is right up there at the top of one of the most important things you need to get right. And I see this so much of the time when I'm out there coaching. People are in the wrong flex boot, and most often it is actually too stiff, or they can't flex it for whatever reason, and some of those reasons you might discover in this podcast today. After this podcast, my hope would be that you are closer to finding the right ski boot fit and flex for you that works for your style and your physiology. Now, after you've got that right, and if you want to keep improving, check out the ski video library on my website, bigpictureskiing.com. There are videos from the intermediate all the way up to the expert, but please don't take my word for it. Check out the 5-star reviews on the landing page to see what other people think and what they are achieving in their skiing. I'm doing my best to pass on all the knowledge that I've gained over the years coaching and talking with people like the expert you're going to hear from today. Let's get into today's podcast with Brent Armsbury on ski boot flex. Okay, Brent, we are going to discuss boot flex. And just before the show started, we were back and forth a little bit before we got started because we want to do a good job on this because it is a topic that can be— it is controversial. You said it's one of the most controversial topics.

Yes.

In the boot, ski boot fitting world. Trying to think where we start, but, uh, one idea was you've got that Fischer boot that's won a lot of awards, and can you show us, uh, show us it right there? And you've taken the top part of the cuff off. And for people listening, yep, for people who are listening, he's got the lower clog and there is this cut kind of right around where the ankle, the sides of your ankle bones would be, and they're, they're cut down like the shape of two U's. Why have you taken this perfectly good boot and cut into it like that?

Yeah, so this boot here was rated, right? So we've got this completely objective side from the manufacturer that says, hey guys, this boot is the pro boot, therefore we're going to call it a 140 flex boot. Now, in reality, the manufacturer is probably closer to 130, 135. The upper portion is actually says it's got carbon infused and so it's a stiffer upper cuff. But you know, out of the box, this boot is actually pretty stout. And my history is I've skied a lot of 130s and I have found over my experience over years that, that just because it's a 130 and I love all the bells and whistles and I get, I get the great liner and I get all the best pieces, but a 130 boot for me, not so great if I'm trying to get the maximum range out of the boot for me.

So when you first skied this one, would you say like you felt— I think you were saying to me you felt really good if you're just ripping groomers on the hard morning sort of snow, but then you felt it didn't suit the way you like to ski things when it started getting all chopped up and you're doing some off-piste runs and some bumps. Is that right?

Absolutely. Like, I'm up at Big Sky, it's early season, they've got, uh, I believe it's Ram Charger, you know, open, and it's, it's got some good grooming. It's where they train, do some race training. And on the groomers, this really stiff boot was, was good. Now don't get me wrong, I was still a little bit bouncing off the front of the boot, you know, to really load it to get a good round carve at the bottom of that, that turn. It just felt like I was bouncing off the front of that boot and I could feel a little bit of a, of a skid happening as I was, that bounce was happening. And I said, this boot's too stiff. And as soon as I took it for a next run, I went, off the groomed run into some, you know, lightly chopped, little bit of fresh snow. This was a rodeo ride, right? Getting no, really no great tip response. I was bouncing off the front. It was bucking me here and there and it was flat out like I knew the boot was too stiff for me, okay? Could have continued skiing it and adapted my skiing to that flex boot, which I had done, you know, many decades ago, skiing 130s and 150s, just adapting my ski to, to a stiff boot. But I learned this isn't— it wasn't going to work. It just wasn't going to work, um, to get the full range out of the boot. And so, you know, I'm, I'm up there at Big Sky and I've got all my tools. And so boom, I I pop the top off and I start these U-cuts because, um, I know this is what I need to do. When I, when I trim down, okay, that top lip right there, from there to there, that's where the plastic used to be. And when I cut down, I've essentially generated more leverage from the back of the upper cuff when I'm pulling that with me to bend this plastic with me. And sure enough, right, the boot went from what I would call like a 130, 135 down to about a 120. And that's, that's my happy place. I know 120 boots are very happy for me, but I got all the great features of the 130 boot or the Pro boot in, but a flex range that was closer to the 120. That's my happy place.

I'm going to jump in here, so, because this is, this is perfect. May we talk here about the, the back of the boot, the bolts in the back? Because why, you know, why I've made some posts in the past and on Instagram about what I do with my boots and some ideas was just to share some more information about what you can do with boots. Because I think a lot of people, like, they get a boot and they fit it in and it's kind of make it comfy, and then that's where it stops. But there's a lot more you can do. And, you know, perhaps, yeah, talk about the, the most common way people understand to change a boot's flex via the back, but then maybe why you would go into the U-cut that you did, right?

So a lot of manufacturers like to talk about tuning the flex through the two rivets in the back. And there's, there's some validity to that to a point. But ideally these two bolts or even the single bolt, it's designed for a reason. It's to tie the base of the spine to the upper cuff. Right. You need these two to link together so that when you push on the front of the boot, everything is moving with you. The lower clog and the upper is moving with you. And they say, well, you can, you can tune it like Head Boots, right? They got 3 holes and Rossi's have 3 holes and you can add another bolt to make it stiffer. You could take one out to make it softer. But this is really kind of an on-the-fly approach. Coaches will do this. Ski instructors will do this. You take one bolt out and it will reduce some of the stiction. It will reduce some of the connection and it'll make the boot feel softer. But where I have a problem with that is that the boot was designed to have a complete connection in the spine, in the back of the boot, pull that, you know, to be pulling the whole boot with you. And so my feeling on this, and I think it's shared by a lot of boot fitters, is that this is really, when you pull bolts, is a testing game. It's like, can I fine tune the flex to be— to give me more range. And what gives me that happy place?

Yeah, that run you were doing, if you didn't know that, you know, you hadn't had the experience you've got with, with changing stuff, it was maybe me, you say, hey Tom, why don't you just come inside? Why don't we just take out one of the bolts? You do that run again and tell me if that feels closer to what you like. And if that's kind of the case, then you can go into a better solution that doesn't, like, ruin the connection of the, of the spine and that spring. Because I think everyone likes that fit. You want a boot that responds. You take the bolts right out, you were saying it's sort of dead, and you sort of just have this almost like a walk mode sort of thing.

Yeah, it's a hinge-y feel. And so, you know, I, I've had that experience. I've taken bolts out of the back of the boot and it becomes more temperature sensitive. Right? Because all of a sudden you've got softer plastic. You've taken, you've taken the, the, the what's holding the boot back away. And in certain conditions, like if it gets warmer, it'll just like free hinge. It's like a door. Woo! Right? And then in colder conditions, it won't. So you generated this massive inconsistency in the boot where I know for a fact if I keep both bolts in and I do the trim cuts, the boot feels just about the same when it gets really cold to when it gets really warm. Yes, it's a little softer, but the progression rate, right, feels really consistent. Not, oh, this boot felt really good when I took the bolts out in the cold. Now it's like a swinging door in the wind on a warm day. That's too much range. Like you've, you've made this boot into something completely different and you've kind of, you've, you've, uh, You've taken the spine out of the boot, right? So, and this is a common practice for, for decades with race boots was to do these type of trim cuts to be able to hold the spine together, right? So that you, you hold this really integral part of the boot in place, not only edge to edge, but fore and aft in the full range of conditions. That you're going to, you're going to ski through.

That's right. It reminds me when I got to interview Ted Ligety and was asking him about his boots when he was changing to the longer radius skis and he became that sort of unstoppable champion. He mentioned he stiffened the back, he added carbon to the spine and got that stiffer, but cut further into the U-section. So like I said, it's not, it's not new. It is something that can be done out there. And in your experience, a good sort of way to go if people are wondering about this is first step, do the thing that is reversible, which is maybe try a bolt out or in, and, and then see how it feels to get a ballpark feel. And then you can go see a boot fitter who can then work on adding this, um, this customization to give you more flex.

But the critical thing about this is that you still need to be within the range of the boot. Like, this is not the answer. If you need a 90 flex boot, don't buy a 130 and think you can do this to make it a 90. This is a fine tuning. Like, these are 3 centimeters deep, and I took a 130, 135 and brought it to 120. If I keep going further down, I get too close to the rivet here. This is going to blow up. I can't turn this boot into a 90 or a 100 or a 110. I've maxed out the physical and structural capacity of the boot to make it what works for me. So you still need to be in the range. You still need to buy a boot that's appropriate for you, and then you can fine-tune it within a certain percentile, right?

Yeah.

You can't transform it.

Yes.

It's, you're just playing with the volume knob. Yeah, you know, on the boot.

Yep, fantastic. So I'm thinking now I want to go back because you mentioned something really cool about, um, so say we take Fischer, for example. Fischer have a, a measuring device that they will put in their boots, and they can on a graph go, this boot, uh, shows this kind of flex pattern, and we know that as this many Newton meters of torque on it And that's with this machine, okay? And you can go— and that's where they get their numbers on all their boots, because they can check the Podium 130 versus the, the new Boa boot and sort of go, yeah, that's why we're going to call them both the 130. However, here's a situation. We've got John and Jim. They both bought the, uh, the new Boa boot and they're out there skiing, but Jim can't flex it very well. John, it's like, this thing's easy, totally feels like, like the 130 boot I had a couple of years ago. What might be going on here? And you mentioned this, this word stiction. Can you explain stiction and why Jim and John are struggling, although they've got the same boot? Why is one flexing more easily than the other?

Correct. Stiction has been a problem with plastic boots ever since we started going to two-piece, um, uh, two-piece designs where we have an upper cuff which wraps around and a lower cuff that wraps around. And so stiction happens when you take material, right, and you— in a ski boot, it's going to wrap around, but you're generating more and more pressure across that contact surface, right? And that Increase the pressure, increase the, the, the, the contact surface, and you generate— it's not so much friction because it's not a continuous glide. It's stiction, which means it's holding that, that surface adhesion. Yeah, it's bound by the surface adhesion, the coefficient of friction on a large scale under a lot of tension. That is stiction. So it's going to take a lot more force to move that material across all those planes than if the material was released and has less contact surface altogether. And I see this all the time with my clients. You got—

because I'm going to tell you, John, yeah, John, he's got the chicken legs. Sorry, John, but Jim, he's got the meaty, the meaty legs.

Why is, why is John The chicken leg guy, this chicken leg guy wants to get more and more, he wants to feel the contact, right? He wants to feel like it's wrapping around his leg, but he's having to buckle to like the 4th, 5th notch, right? All the way over. And so this, this whole cuff is trying to go smaller and smaller and smaller. And so all these pieces are wrapping more and more surface area around with greater tension. Okay, so John feels like that's tight, that's good. Like, I feel the contact, but then he goes to flex it and the stiction is through the roof. It's like, bang, it's not going anywhere, right? It just can't get it to release, right? So Jim, right, has a big leg, big thick leg. The boot barely like the first notch and it's snug, but there's not a lot of real estate that's making purchase there, right? The boot's in its widest calf position. The, the cuffs are barely touching each other. Jim can just flex it, no problem, because there's no stiction. There's literally no stiction in the boot. Nothing is really holding it there. Now, Jim might be a bigger guy, you know, John might be a smaller guy, but they might have actually the same— they can bench press the same, right? They may have the equal amount of strength, but that boot is on Jim's side is providing very little resistance and stiction, where there's way too much stiction with John.

Yep. And that's a, that's a tricky thing, isn't it? And sometimes people maybe don't think about when they're trying on boots, that volume around your calf, that upper calf area again, like you're saying, like you don't want to take a 150 boot and turn into a 90. Your, your calf volume, ideally you're going to try and get that so the boot closes— same with all sections of the boot— without too much buckling, right? Because otherwise you're going to run into these problems and the whole characteristics of the boot changes, right?

I mean, the boot almost always flexes more naturally when you're in the middle of the range of the buckles, right? Number 2 and number 3. Yeah, that's exactly— I mean, when I, when I go into the factories and I see the flexing machine and they're doing the longevity and they're trying to see if, you know, after 100,000 cycles, how much the boot is softening up and, you know, how many Newton meters it's producing, etc., etc. Now, don't get me wrong, there's no calibration for this. They're just saying in that boot at that level, at 130, we want it to have about that much, you know, and it's got to have a certain amount of longevity. Gravity, and they're just seeing if other things pop off and break off and such. But they're using a certain diameter of leg, and that's the leg model. That's the perfect leg that goes into that boot, and it's going back and forth and back and forth and back and forth. They're not saying, well, here's Jim's leg and here's John's leg. They're not putting, you know, a pencil in there and then wrapping around. They're not taking a ham hock and putting in there and wrapping around and testing it. They're taking the absolute leg model, the median value of a leg shape, and testing it with that. And you can see where the boots buckle, like the second and third buckle, you know, like second, third notch on the clasp, PowerStrap, you know, right in the middle and testing that boot. Objectively, that's where it's at. And if you're outside of that, it becomes very subjective, right? Buckling it tighter makes it feel stiffer, feel stiffer. Buckling it less makes it feel softer because you're generating more range because you're not getting as much initial stiction. Yeah.

Yeah.

So, and this, this is a dilemma, right? This is a dilemma that manufacturers have done deal with fear. Like, look at this, right? This is the 3-piece boot, you know, many years ago, 1979, '80, that said, let's, you know, stiction was an issue. Let's make a tongue. That controls the flex. I'm not saying this is, you know, your answer. I'm just saying it's an issue that designers, manufacturers have been dealing with for a long time, right? Yeah. And you look at the touring boots, they use a 3-piece design, they're using a tongue. They're not trying to generate all these pieces going together. Yeah, it might be a little lighter, etc., etc., but it's— they're trying to address the fact that they know that when too many pieces come together and you put too much pressure on them, the number that's on the side, you just throw it in the trash can. So it doesn't work.

I know, I know John and Jim are probably listening to this, and, and John, who's got the skinnier legs, is like, right, okay, well, what if no boot comes skinny enough and I'm always having to buckle them up a bit? Brent, what suggestions have you got for me to try and make this a little better for me?

Well, it depends on the design of boot, right? So if we're looking at a two-piece boot, we can— if you need to buckle at the end range, we can do tongue modifications, adding padding to the tongue, adding some external material that might not interfere with the flex but doesn't require you to buckle quite so tight, right? Um, we can tune the boot, soften it, right? Give it more range. But ideally, you probably— the first thing we'll do is change the shape of the tongue and change the volume around your legs so that that boot, when it closes, is more in the middle range of its clasping.

Yeah, I just had almost a bit of an epiphany too of why sometimes people have such a revelation with spoilers too, because that's also helping them get a better volume fit, not having to maybe buckle it up. That's changing the flex. And so all these things, it's not just the angle change, right? You're changing the flex pattern of the boot as well.

Probably you can check that spoiler on the front of the tongue, right? Not on the inside, you don't want to have that, but on the outside of the tongue, you could slap it there. And when the boot's closing, it's closing earlier, not quite as much excessive pressure to close it. And you go, whoa, this boot feels more natural because I've taken some volume in the tongue. I mean, I've even used— my leg is thick on the top, a little narrow on the bottom. I've actually taken neoprene, and we've talked about this before, lining the front tongue with two layers of neoprene on the lower section to feel like when that boot closes on the second buckle, I'm not having to throw it to the fourth clasp. It's like it's number one or number two. I got the contact feel. But I'm not binding that boot up. It's no longer binding on this, on the plastic to generate all that extra stiction to make that, that boot feel extra stiff even though it really isn't.

And, and, and let's not forget Jim, maybe if he's like, you know, the people out there that are just crushing boots, I mean, my first thought would be maybe they could look at a custom liner that's thinner to give themselves a little, you know, they're not filling out a boot so much. I don't know, any suggestions for, for that?

For that, um, generally speaking, when you have a really large leg, okay, um, there's a really good boot fitter out there by the name of Gord, and he does a beautiful job of transforming these upper cuffs for large legs. He's adding plastic, he's adding another extended cuff. Because that by wrapping around puts it within more of the actual range that the manufacturer intended. The big leg, you know, it's barely closing. Now he's adding an extension. It closes more naturally. It actually increases the sticktion, but it actually allows that boot to flex in the range that it was originally intended to. So the big leg guy, actually, you actually need to add material. And with the thin leg guy, you're taking away material, you know, in terms of like the plastic, but also adding material inside to bring it within balance. Okay.

Yes, yes. Yeah.

Is that—

I know I've seen some good things from, um, customizations from Gord on that. So yeah, because I know we've done some podcasts on the people with skin, lower volume, but then the, the higher volume person, they also need, need some help there. Um, so on that, there was— I've also heard, just, is there someone that makes an, uh, like you can buy that custom kind of plastic thing to stiffen the boot? Maybe Pulse Labs. I don't know if I'm—

yeah, Pulse made a, an extension to the tongue, right? He— they made this, it was P-Bax, and it was an extension to the tongue. It made a boot stiffer by adding, again, more material. It was now a third tongue extension and it generated, now you have 1, 2, and 3 pieces on top of each other. And so now you have the added resistance of the accessory, of the appliance tongue, plus the overlap, increased diction, increased stiffness from the material itself. If that's what you're looking for, right? Yeah. But these type of devices could almost be home built. Like you can take an old pair of boots where the plastic is not crystallized and breaking like, and, and literally cut an upper flap out of it and then make an extension and, and then adjust it vertically. 'Cause you know, you've talked about where, where the upper cuff hits right here, right?

Yeah.

If you bring that plastic further down and you flex on it, it's gonna impact the lower. And start to bind up faster, right? At the end of the range it goes boom, we're done, let's go. If you bring it higher up, it allows more range. So there are modifications that can be done on a boot to not only make it feel more progressive and softer, but also to make it feel a little bit firmer at the end range or make it feel firmer throughout, throughout the initial That's probably a good thing to cover here too.

I asked you offline, but like, what, what are you looking for in that ski boot flex that tells you it's, it's right?

Well, for me, right, is you— that it moves with me, right? When I'm flexing, I can feel the boot move and flex with me. It's not, it's providing resistance. You bet it's, it's resistant, but it's not fighting me, right? It's, yeah, I can move my center of mass over the tip of the ski and expect it to load at a consistent rate. And then it says we're done. When I'm at my end range of ankle range of motion, that boot's done. It's, it's loading up and it says, we've flexed enough, it's time to release and exit.

Yeah.

If the boot is too stiff, I'll feel as if I'm moving, but the boot's not moving. And then I hit a wall. I hit literally like that.

Yeah.

Not boom and back. It's, yep. Okay.

It's kind of like, and if you were an arti— like someone was able to artificially integrate this boot into you. You want it to sort of meld into a feeling of like, as your ankle flexes, the calves are kind of controlling that. The boot is, is feeling like it's part of that process, as opposed to your leg just being inside of something and moving.

Correct. Yeah, yeah. You're not whacking. You don't want to feel like you're whacking back and forth. You wanna feel that you actually feel resistance. That whole boot is wrapped with you and you feel this progressive increase in tension till the end of the range.

Yep.

Of your ankle range of motion. And it's not, it takes time to figure it out because inevitably we tend to buy boots a little too stiff for our capacity, for our ability levels. And of course we wanna be better skiers, And so I went, I mean, man, I went through decades, literally decades of skiing boots that were too stiff for me. And I thought that was fantastic, slamming on the front, feeling this really big abrupt hit and the skis would just kind of slide and move across the hill. But it was really hard to make a nice carve turn. It was, it was just sort of a touch and go feel. And that's fine if that's the way you wanna ski, but to make a Shape Ski work, I found myself skiing softer boots. And I didn't, I didn't get to this by just this thing working. It was by accident. I literally took back a pair of boots I sold to somebody and they didn't like them. And so I gave them their money back. You know what? I made them my own. They weren't the top of the line boot. At the time. They were the two steps down. And I'm like, you know what? They're the right size for me. I'm just going to throw these liners in there. I'm just going to go ski them. Why not? What am I going to do, throw these things away? I can't sell them to anybody. So I took a boot that probably at that time was a 110 flex, right? 100 to 110. And I went and skied on this thing. And I had, you know, shape skis like, you know, 10-meter, 12-meter radius skis that were really the cool thing at the time. And guess what? I skied better.

Yeah.

2 night sessions into with these, these, these boots. And I was like, this is way different. This is way better.

You had that feeling of like the boot was more like part of your anatomy.

You're part of me moving with these, these carves. These, these deep radius skis were just coming around all the way. I was working way less. I was skiing better. Yeah. And I was like, I don't need a 130. I don't need this boot anymore unless I'm going to ski a certain way. And so really, what are my boots? They're 110s, 120s now. Like, they're really— if I'm skiing in the backcountry, it's a 110. If I'm skiing on the groomers, it's a 120. I don't mind the 130 pro model. I get all the features, but I know how to tune it.

Can I explain why I've gone to the, to the stiffer end? Because I remember, I remember talking to you. I was like, Brenda, someone gave me these 150 podium boots. That's a plug boot. I've, I'd never really owned a full plug boot like that before. And you're like, Tom, you're gonna feel, you know, this, this, and this. You're going to feel more edge grip, you're going to feel more responsive, and it's going to be damper. And I'm like, right, I'm ready for that. I, I want that. Because up until that point, I'd had, I'd had a pair of like 110 Head, uh, those red Raptor boots. I'd had a pair of the, the Lang when the, the new, the RS when it first came out that I got from you in a 130. They definitely felt softer than a 130, but loved, loved them. And a Dalbello 130, and then, um, Scorpion 130. So lots of boots that I'd been fine in, and I wasn't looking for going to the 150 any more resistance inflection. That was not at all like the thing I was looking for. I was looking for edging responsiveness, especially how I have to ski in New Zealand, Australia, and I like skiing fast and carving. So I wanted that responsiveness, and so that's why I went to it, and also to learn and try it. Like, I'd never— like, why do these other people I look up to ski on this 150 boot? And, and, and so forth. So anyway, it's been a really interesting experiment. I definitely found all those attributes of edging and, and so forth. I felt more power, more grip on the edge, and I've fine-tuned, as you've done with your, your Boa boots, the Fischer Boa boots, the flex a little bit. So then I still get this like nice range. So when I go ski powder and moguls, um, it's, it's still good. But I would say I like— I can remember the first time I skied some sort of powder on top of sort of junky snow and, uh, in these 150 boots. And I was a little bit scared. I could tell that I didn't have the same kind of give, or, you know, what it was like— I was taking my, um, my mid-range mountain bike down a downhill trail instead of my downhill bike. But I'd made this decision based on I wanted to feel more comfortable with the carving end of things. So anyway, just thought I would mention in there, that's why I've gone that road. I was looking for these attributes. I could fine-tune it a little bit, but yeah, I would love like a 110 Podium tuned up for just bumping and powder skiing.

Sure. And you know, there's another notion with flex that we should probably talk about, and that is you've mentioned out there that, you know, thicker plastics mean stiffer. And there's some truth to that, right? Like, you get a plug boot and the plastic is definitely thicker, but the, you know, the formulation of that plastic is, you know, going to be different. You know, like, if you want to make a plug boot, you can make a 90 flex plug boot. The formulation is going to be a different formulation and it'll feel as a 90 flex. But you can also make a thin shell wall boot that's super thin, like a touring boot or a freeride boot, and still make it objectively a 130. But you're moving a different level of mass. So the thick shell wall boot has more mass. Okay? There's more material. Doesn't matter the formulation. You're moving a thicker piece of material through its range. Okay. The thin shell wall boot, really thin. It's going to feel— it's going to have that resistance. But at a certain point, when you take a thinner material and you bend it far enough, it starts to distort. It's going to go like give way. It goes bye-bye, right? Things start to bulge and move out. Not because it's lost its integrity, it's just past its design limit, which was it needs to be stiff but light, right? You get into a thicker PU boot that was designed to dampen and to have this more progressive spring rate, it has to be thicker to do that.

So give us the example. I think, um, maybe Because this is a really awesome thing I learned. In the, the difference between like the 150 race boot and the 90 flex race boot is not the thickness of the plastic, because, because those boots are designed to grind and blood. So you, so you want the thickness there so people can customize it, and the weight also correct to sort of give us a certain feel.

So they're coming out of the same mold.

Coming out of the same mold.

They're coming out of the same mold. So the thickness—

So how do you get the 90 to flex different to the 150?

You change the formulation of the plastic. So you can take a PU and you can add in softeners. It might be polypropylene, it could be polyethylene, it could be PCL, polycarborolactone. You're gonna mix in, in that PU blend, materials you know, pellets that make that boot softer, right? To get the stiffer boots, you're going to mix in additives that make that PU stiffer. Same shell wall thickness, it's just one has a completely different formulation than the other.

This episode is brought to you by Carv, the digital ski coach. Now, one of the features I've had the most fun with all time is simply the fact that Carv tracks every single turn you make. I treat it a bit like Strava, so at the end of the day it tells me exactly how many turns I've done, and those numbers keep adding up across the season. So last season in Australia, I had a few days where I was doing nearly 2,500 turns, and my legs were tired, but it was really cool to try and have that number there motivating me. And I'm quietly working my way towards my 1 millionth turn with Carve. So the other metrics I've been diving into lately, and these are new for this season, are very unique, and these are Turn Corridor and Turn Radius. And I don't see many skiers using them, but they tell you a lot about the shape and flow of your skiing. So the Turn Corridor shows you how far you're traveling across the hill, or the time almost between apex to apex, and how long you're taking to transition. While the Turn Radius measures the actual arc you create once you start the turn. So these can be different, you can have like a very wide corridor, say 18 meters, but a lower turn radius, or the other way around. So when you compare the two, it opens up a whole world of experimentation, and it would be a bit like a race coach will set different types of race courses to influence a racer or skier to change the timing and mix it up. So I encourage you to look into this if you've got Carv and play with it and see if you can manipulate it, because it's only going to improve your versatility. So I keep my Carv on my boots every single day because you never know quite know when, like change in technique or a new ski resort or skis will show up in the numbers. And it's great at the end of the day being able to check that, or even after the fact. And I'm really looking forward to the day I open the app and I see turn number 1 million. So if you want to explore your skiing in a completely different way, check out Carv, the digital ski coach. And thank you, team, for sponsoring this episode. Yep, so those— that's, that's a good thing to consider. When, when you're looking at a boot, the flex characteristics are gonna— like, they'll present and feel different because of these two things. Not only the thickness has an, has an effect, but the formula or the, um, yeah, the types of the mix of the materials.

Lens. Yeah, the blends of plastics, right?

Yeah.

Um, and, and like, you know, when— like this boot right here, right? I ski this boot for years. This is a Head Edge Lite 130. It says 130. When I put it on and I flex it, it felt like a 130. But there are parts of this boot that are only less than 2 millimeters thick in the plastic. Why? What they wanna do, they said light, right? It's light. It's easily 30% lighter than a PU boot and that feels different. But what happens is when you make that shell wall that much thinner and you start pushing it all to the, all the way to the end range of your ankle range of motion, right? Full deep flex. That plastic just goes, bye. It just, it lets, kind of lets go. This boot wasn't designed for that. It was designed for you to stand up, wider ski, softer snow, having a good time, taller stance. But when I take that boot and I try to put it on a very a narrower ski, firmer ski designed for firmer snow, that boot is only a 130 in the first 20-30% of its flex range. And then on the back end of the range, it just goes, see ya, nothing there. Now, if I take a PU boot, the race boot, 6, 7, 8mm shell wall thickness, doesn't do that. It could be a 110 plug-type boot, and it will be far more progressive and far more consistent resistance through the full range of flex than that 130 with a thinner shell wall. And that's the subjective side, right? We objectively— it is still a 130, but subjectively, the way it performs on the snow and within its design limits, it's a different flexing boot. Yeah.

Hey Brent, let's, let's bring out this boot that you've been enjoying and, and explain to us what's— because there's some cool different factors in this boot, and the one about pressure, I'll let you speak on that. But listen up to Brent explain this thing on pressure and the fact that, yeah, this boot is sort of like, like you said, it's just they, they got the, the brand has no real heritage in ski boots. They've start from wherever they want and they've designed this. Show us.

So this is, yeah, this is a boot that I just picked up, um, at the end of the season. Um, I've had my eye on it for a couple of years in, in, on online. Was wondering if it existed in reality. Um, it is a 5-buckle, 5-buckle boot from UPZ. Now if you know You've probably never heard of UPZ unless you're a snowboarder and you're a, you're a carving snowboarder, right? On a hard, on a hard, hard plate binding, hard boots and carving snowboard. This is a company that produces a ton of the World Cup snowboard carving boots. And the designer of this boot said, hey, I love to ski. I've got a clean slate. I'm just gonna make a boot with a completely different way of looking at a ski boot, um, from the hole underneath the heel. Yeah, right, to the 5 buckles, which is, you know—

now I'm gonna say the 5 buckles, like, what you would think, oh, tell us about that, the importance of that. But I think the most interesting thing you mentioned— can you start with the boot sole length and explain that?

Right. So they incorporated a feature that they used in their snowboard boots, which is an incredibly small boot sole length relative to the inner length and dimension of the boot. So I ski a 25.5. That's a, that's a very snug fit for me. A 25.5 boot sole, the BSL, the boot sole length on a 25.5 is usually about 295 to 297.

Millimeters.

This is a 25.5 with a 287 BSL, boot sole length. So it is technically the same boot sole length as a 24.5. So I'm taking my mass, right? And I'm putting it over a boot sole length that's considerably smaller in length than I would normally, normally ski. I.e., it generates more pressure, PSI, pounds per square inch.

I'm gonna jump in there because I think that was the thing I was like, oh wow, that's really something I've never thought about. So Brent is just saying usually when he clicks into his bindings in his 25.5 Fisher Boa boot, it's like 297.

Yeah, I think it's 297 to Uh, it's actually 293 on my boa.

Okay, okay, so 293 millimeters long. Yeah, that's the boot's length. And then this boot, same kind of internal fit, it's a 25.5. However, the way they've designed it, it is shorter, it's 287, so half a centimeter shorter. And other brands, little, you know, other brands in a 25.5, like you said, can be up as high as like 297 297, 298, even 300. So there could be a 1 centimeter difference in the length. So you'd have to totally adjust the bindings, make them shorter to get this UPZ boot in there. But the felt difference, because of the physics behind it, is like, this is pressure over an area. You weigh the same, but the— but where you're standing on is smaller, just like if you were standing on even smaller spot it had put even more pressure into that one zone. So yeah, what did you feel? And maybe it's not everyone will feel it, but an advanced, you know, someone who's into their skiing would maybe feel—

yeah, I mean, it definitely feels different. So, uh, sorry, it's 290— sorry, you know, my— I, I need glasses. 296 on my BOA. Um, so I used to ski a lot of 26.5. Right? Back in the day, 26.5 was about the right size, and that was a 305, 305, 306 boot sole length. When I jump into a 26.5 and ski that of an, like, an older boot, and then I jump into this at 287, it's a really, a huge difference. Now, between the 296 and the 287, it's like, okay, I can feel it. And the feeling is it's got a lot more punch, right? When you step on that boot through the ski, that ski, I would say it feels like it's sharp. The edges are sharper, but I haven't touched the edges.

Yeah.

So that ski is literally bending more directly underneath my foot because I'm increasing the PSI. Through the middle of that ski. I'm going straight through the middle as opposed to spreading out the pressure over the top length of that ski.

Because can you explain— I like— some binding manufacturers have been trying to help this effect on a pair of skis by, by them not being too long, like extended. Correct.

In multiple ways. Yeah, right. This is why that Look Pivot is popular, right? You're putting the screws right in on a Look Pivot. You're actually stepping— I mean, it's extending up and over, but you're— it's a shorter mounting point. The old Marker Rotomats that way. Tyrolia FreeFlex. What do you think they call it FreeFlex? It's because they literally have the heel on a track that's floating through the track so that the point, you're really only impinging on one point, that's the toe piece as you're flexing. Every binding manufacturer over the years has tried to say, we know that when you fix two points here, all right, and you bend it, these will constrict, all right? They'll constrict on the toe and the heel and impede the flex of the ski. But also a shorter, a shorter boot sole length also bring those points closer together, therefore reducing and increasing the pressure and reducing the amount of pressure on the, on the toe and the heel. The impingement points. Yeah.

It helped me sort of conceptualize this when I just imagined, I was like, okay, take Brent's idea and just expand it even more. Like what if I had to my 26.5 boot, but it had like a, you know, it was double the length under my foot of solid plastic. And I stood in a ski, I could just imagine it would just feel really flat. The ski wouldn't feel like it could flex much, right? And you would feel when you, when you tried the Apex boots, which are kind of like, you know, you've, you almost, you step this snowboard boot into a frame, which is obviously going to make it bigger. So for like the 25.5, it was 317 or something you said.

Yeah, it was really long. It was like really long. And the feeling was, you know, I'm not here to throw those guys underneath the bus, right?

Like, absolutely not.

You know, I went out and skied on 'em and they, they skied okay, but the feeling was really much more dead, right? I didn't feel like I was punching through the bottom of the ski. I felt like I was just kind of tipping things back and forth and the ski was just kind of doing what it was sort of designed to do. But I was, there was no punch. Right? I, I couldn't feel like I was actually getting the ski to completely bend underneath my foot, right? I couldn't feel that, that springboard effect, um, with that long of boot sole length. And there, don't get me wrong, there's a lot of skiers who this is not, this is not designed for. Like, we, you don't care. You're just having a good time. You just wanna get down the mountain and smile and, and your feet not hurt. Yeah, your feet don't hurt, and that's, that's great. But you can drive a Toyota Camry or you can drive a Porsche 911, right?

Yep. And I'd say a lot of people listening here are the ones— maybe we don't, we can't, but we would like to be driving Porsche 911s if we could.

Okay, so you jump in a sports car, you know, and it's got a completely different wheelbase and a completely different suspension, and it's putting more G-forces to the road, right? Like, you throw it in a corner and it punches through the corner. And that's the difference, right? You get on a boot like this with this little tiny boot sole length and holy moly, this is driving a 911, right? It punches through the bottom of the ski. It makes the ski— it takes a mediocre ski and makes it feel like it has sharper edges and more torsional grip than it ever had before. It's, it's a pretty amazing feeling. When you've taken a product and given it just a completely clean slate and done some, you know, you're not bound and constricted by a precedent and you're doing stuff that's really different.

It's so cool you bring this up because, you know, you and I, we love skiing, we're in this industry, you know, for the long term and just people that innovate and come with different solutions, you know, and but play with tangible things like anyone, like you can look it up. What is pressure? Like, you know, force over, over area load. So, you know, they're just playing with these parameters within, you know, what they can do. And why they haven't done it so much yet in, like, say, a race boot is because of the height, isn't it? So do you want to maybe just touch on that? Because that's something—

so manufacturers with race boots are trying— they, they do try to go the shortest possible boot length. Um, that is definitely like in Nordica's new Doberman, right? They that is a pretty small boot sole length, um, relative to the internal length. They know that the racer's gonna downsize, right? So they're, they're actually generating as much room as possible internally over a shorter boot sole length, knowing that with the proper sizing, they're gonna go to a much shorter boot sole length than normal.

Yeah.

Yep.

So, but they've, they've got around it.

But you can't raise the, I mean, to do it, you actually have to raise the heel, right? You have to actually raise and then stretch over the back and FIS requirements, right? Requires that that heel can only be so high internally. This UPZ boot, it's like, no, it's, it doesn't meet any FIS requirement for that. Okay. For, for alpine racing. And so, and they don't care. Right? They're just like, we wanna do something really different that puts more pressure to the ski. Because we don't have to make a, we don't make race boots. We make an alpine ski boot that does something completely different because we're not bound by any restrictions.

Yeah.

Okay.

Yep. Brent, I wanna just say thank you for spending the time to explain this sort of stuff because that's the reason you know, we did this is to get some more knowledge out there. Sometimes it's difficult to find information, uh, on, on different topics, whatever it is, around, you know, around the world. But with the internet and things coming, you know, more accessible, things like this help an expert like you share, um, thoughts with people so people can find that ideal ski boot so then they can have more fun on the slope. So I, I really appreciate you spending the time to, uh, to do this, do you want to, one, give a, like, uh, your quick kind of summary on the BootFlex that we've discussed today? And then, uh, and then two, if people want to find you, how can they find you and utilize your services even more?

Well, in summary, in terms of BootFlex, is that we do want to stay, you know, within the parameters of our skiing abilities and purchase boots that are within our range and our capacity. Okay. Let's not get too caught up in the marketing, right? That you need a stiffer boot all the time. You don't. You, if you feel you need a stiffer boot, you know, get good advice, try boots on, right? Flex them indoors. Try to find, you know, the boot that feels like it's moving with you, right? It closes when there's a certain range, it moves with you. And that could take— that takes time. All right. I've seen customers do what I call boot yoga. You know, it's the, it's the older customer who spent a lot of time in boots and they literally do boot yoga in the store. Where they're flexing the boot back and forth and they get in all these really contorted positions. And you know what? They're right. You should be doing boot yoga, not just, hey man, I read this magazine, I saw the ratings, I want this boot, and you just take 2 minutes and you convince yourself. No, spend some time, do some boot yoga. I do boot yoga, right? I put a boot on and I flex the— I walk around in the store, I boot fit with a boot on. Bouncing around in and spending the day in it. And it tells me what's happening, right? So, um, get to know, try boots on, get to know them and see if you connect with the way they move and they flex and they feel like they're part of your body. Okay, that's not just fit, but, but how they move with you. Okay. Yeah. Um, and I'm happy to answer questions. Many of your Viewers have sent me emails. Summertime is actually a great time because I've got more time. You can reach me at Park City Ski Boot, which is PCPUTAW@gmail.com. I'm happy to answer questions, but when the winter arrives, I'm really busy. If you send me an email and I don't respond for 3, 4, or 5 days, Um, don't be freaked out, okay? Because I get a lot of email, I get a lot of questions. I'm happy to respond and give you my opinion, but, um, be patient when it's ski season. And I'm happy to work with you when my availability becomes available.

Yeah, awesome. Yeah, and I think it's just, it's fantastic because the you know, experts in every field out there, but experts are sort of fewer in numbers. So you, you know, there's people going to be listening in all corners of the, of the globe and parts of America and Australia, Canada that might not have access to someone like you or, or other experts. And the purpose of these things was to give people a little bit more information so that they can have a conversation or help narrow things down to when they decide to, you know, really go for that new pair of boots or whatever it is. That's, that's the goal here. Um, and I'm saying this because I know I have maybe annoyed some people out there. It is not my intention. I'm going through a process of figuring things out as well, and, and as I find information, I share it. And then Brent, someone like Brent, helps enlighten me on all these other new things. But without doing that I don't learn keeping the information behind closed doors. We don't learn. So I really appreciate you, Brent, taking the time to, yeah, freely give this knowledge.

And there's one more point I'd like to make. I am sort of, I am part of a ski boot fitter sort of Illuminati, right? Sort of a, an inner group of boot fitters throughout the world. And I can help you find a boot fitter just about on any continent. Yeah, there's some vacuums out there for sure. But you can say, hey, I'm going to the Alps, this specific area, who do I talk to? I'm going to Australia, I'm going to New Zealand, I'm going to Japan, I'm going here, there, wherever, wherever in North America. There's an incredible group of boot fitters out there that have great knowledge, great understanding of the concepts and can really help you. And they're, they're spread all over the world. They're really smart men and women out there that are capable of helping you get it to the proper fit, the proper flex, the proper performance level. And so feel free to reach out and go, hey, I live here, where would I go?

How can people— yeah, where can they find that, um, that group?

Well, this is a private Facebook group. It cannot— you cannot access it on its own. This is, like I said, it's Illuminati. It's BooFitters talking with BooFitters and trading ideas. We are our own, um, you know, group and our own, uh, you know, alliance that tries to exchange ideas through a forum. It's not designed for the public, but if you need access to find one, you can contact me and I can reach out to my colleagues all over the world and say, great. Yeah.

Okay. So if they, if they wanted to find someone, get a recommendation.

Yep.

It's okay. Be cool if you could even set up something where it was, yeah, list of recommended. I don't know. That would, that would be something pretty neat.

So that was tried.

Okay.

There was actually a really wonderfully dedicated human being in Austria that tried to do that, and it just ran out of steam. And it required paying, it required, you know, shops to pay into it, and it just didn't take off. It was Winter World Connect. And it was a beautiful website. It was, it grew incredible great intentions. And unfortunately, that was the whole design was to try to bring all the bootfitters onto one webpage, but it costs money and bootfitters are not all independent with their own access to budgets. And so they would rely on the owners and the managers to say, yeah, you've got to pay for this to get us on there. And, you know, when it comes to money, you hit walls. So, But there are, I have incredible colleagues all over the world that can help people, right? That can, that can help people give them advice, provide them services and even refer them to somebody else along the way if, if need be.

So someone is looking, they can give you an email and ask, you know, to where they live and they can ask for a recommendation.

Absolutely.

Thank you. That is— not everyone emailed Brent. I have no spare time left.

Again, you know, to do that, it's not going to be the fastest response time. And, you know, keep in mind that, you know, once we hit the ski season, my response time, you know, really starts to slow down.

Yeah. So, yeah. Oh, absolutely. Mine too. Brent, thank you again for your time and expertise, and thanks everyone for listening.

Yeah, thank you, Tom.