Have You Checked Your Ski Binding Delta Angle? It Could Make You Ski Better

Hey skiers, welcome back to another episode of the Big Picture Skiing Podcast. We are looking at binding delta angle with Lew Rosenfeld today. Now essentially, this is looking at the difference in heel height to toe height in your bindings. Now you're going to find out that measuring this is something really important you should be doing because there is an ideal angle or difference between the two, whether it's some or completely flat, that will make it easier to do the type of turns you want to do. Now, I've spoken to Lou about this because Lou has a lot of experience and a lot of, has done a lot of research in binding positioning. And so Lou is very knowledgeable in the area of binding setup. So he recently had a young boy come in and speak of a pair of Atomic skis like absolutely changing his skiing, like to the point where Lou was like, hang on a second, there shouldn't be that much of a difference between say one brand and another. So being suspicious, he went and checked the difference, and of course there was something to do with the binding, binding delta angle, and there was actually a 6mm difference between these two brands. And coaches, the kid, they all spotted he skied better with a flatter delta angle in his bindings. Now, this is a really interesting discussion. It's not very long, but we want you to go away knowing some information, knowing some things, and being curious and interested in checking your own ski binding setup. And this is just going to help you in future and also eliminate some of the things that are like, well, I like this ski, but I don't like that ski. You might actually find some actual quantitative kind of measurable stuff that is why that is so. Now, if equipment and setup is important to you, uh, like it is to me, then I invite you to check out the Big Picture Skiing website. I have a category dedicated to all the little tweaks, modifications, things I've learned about ski boots, whether that's liners, shells, footbeds, and bindings. I put it all in there so it's easy for you to find that information in one spot. Now without further ado, let's get into the podcast episode with Lou Rosenfeld on binding delta angle. Now if people haven't heard of who you are, there's a podcast that we did together a few years ago, and Lou talks about research done on binding placement. So that's along the length of the ski, right? More towards the tip or more towards the tail. And you did some work with Atomic and some other, other, uh, institute.

Atomic and Nordica.

Yeah, to find out. Yeah, and you used, uh, pressure graphs, pressure sensors to measure like what was going on fore and aft and how skis reacted. And then also experiential, I guess, uh, responses of like, do you like it here? Do you like it back or run 1, 2, 3, or 4? Which one felt better?

Right.

And that was fascinating. And people have found that really, really useful. I found it seriously useful for myself. And funnily enough, I went like more forward and now I'm actually thinking of coming back a little bit and I'll explain why later on.

But, well, yeah, we should say, we should say, and maybe remind everyone that we did that 2 or 3 years ago, I think. Right. So by then you've skied probably a new pair of skis every year. And the binding position that Völkl has marked on your new pair of skis may not be the same binding position as it was on the one before. So it's possible that they've moved the binding position forward.

Well, no, here's the good thing, because I have it. Völkl doesn't— no one sponsors me. So I had— it wasn't these skis. These skis are more forward, but there was one after that and I tried them, had them forward. Just after we chatted, and then just recently skied a lot on those slalom skis in the States. And I'm just feeling— and it's because I've gotten better, I have my own ways of getting the tip to engage that I don't sort of need it. But you know, it was the, the brilliant thing— and we're getting off the topic of what this is about, but while we're here, what was good is it gave me a sense of like, oh when the tip is pressured this much, this happens in a turn, right? And because I was kind of more closer to that point, I got more experiences, felt sensations, trusted what happened, right? Now I can come back a bit because I'm feeling it's almost like the reaction is, is sort of too soon for what I want to do with my turns now. So interesting kind of, uh, yeah, development. But you know what, today we're going to discuss, and, and this gets people— there's certain words in the industry that are correct, but basically we're going to look at the angle between the toe piece of the binding and the heel piece.

So, and we're going to call it delta, not ramp.

Okay, okay, we're going to call it delta. And then possibly we will get into also the ramp angle inside the boot, inside of the boot board. Yeah, so there's those two angles, but the first one, you contact me saying, look, I think we should discuss this because this, this binding delta is really important and makes a, makes a big difference.

Right.

Lou, first of all, you sent a video. I'll play the video now of how you measure it.

Okay.

And then we'll come back to that and then go forth.

Hi, I'm Lou Rosenfeld. For the past 20 years, owner of Lou's Performance Center in Calgary. And the purpose of this video is to teach you how to measure binding delta. And binding delta is the difference in height between the heel of the binding, or where your boot rests on the heel of the binding, and where your boot rests on the toe of the binding. And on the toe of the binding, it rests on the AFD, which is that white Delrin pad you can see. And AFD stands for anti-friction device. Every binding in the world has one. It might not always be a white Delrin pad, but there's something there, and that's what you're going to measure. So it's a really Really simple process. I'm going to use a digital caliper to do this, but you don't need this kind of accuracy. Great if you have one. A cheap one like this is not very expensive, $10 or $15. But if you don't want to do that, every bike shop sells a plain sliding caliper. I bet you'll find one for $5. And there are other ways I'll show you. I'm going to come to the back here, to the heel piece. I'm going to measure on the highest part of the plastic housing where the boot would sit, rock back and forth just a little bit to make sure that I have the caliper flat on the bottom of the ski, and then measure. And I got 38.27 millimeters. And then I come up to the front. And I measure the front, and I got 27.77mm. So almost exactly 10mm, but I didn't try and keep the numbers in my head, so forgive me if I'm off by 0.1 or 0.2mm. I really don't care about the 0.1 or 0.2mm, I care about the big numbers. So the binding delta of this binding is about 10mm. That's all we are trying to get out of this video. If you can't If you don't want to, if you don't have a digital caliper, you can do this just as easily with an adjustable wrench. Clamp it down like this, pull it off, use a tape measure to measure the distance between the jaws. That is the whole incredibly difficult experience.

So, Lou, you're encouraging people to go out and measure this toe height, heel height, find the difference, and then what can they do with that information?

Tom, you put the hardest question first. They can't— what they can do with that information, and what prompted my call to you was that what happened was a friend of mine who has a son that races, and his son is 13 years old, so he skis well but got a long, long way to go. Right? And he, he was on Rossi skis, and this spring he tested Atomic skis, and his coach and everyone said, oh my God, what a difference! Atomic skis, you've got to ski on Atomic skis. And you and I have been around junior skis, and I mean, I, I wouldn't even say there's that kind of differences if we're talking about Völkl to Head to Blizzard or whatever, you know, there's differences that I like one more than the other, but I— it isn't like I get on one and all of a sudden I ski better than I ever have in my life, right? And this was a dramatic difference. And I said, yeah, something else is going on here. And when we measured the binding angle, Rossi has a very high delta, 6mm, and that's high. That's about the highest in the industry anymore. It might be the highest. And, and then when we measured the Atomic, there was zero binding delta. So we still need to run the experiment to prove it, but, and it's too late in the season to do that. But I'll tell you, it wasn't the difference in this unbelievably high quality Atomic ski versus the trash Rossi ski. It's the difference in the binding delta. The binding positions for an F were virtually the same. So the skis are virtually the same except that he's standing like this. And this kid is pretty heavy, not very strong yet, more like a big German Shepherd puppy, right? So he—

Right.

—waves around a bit. He needs to have something solid under him, and being on a flat surface feels a whole lot more solid than being on a surface like that. And that's what prompted this. Mm-hmm. Yeah.

Yeah. And, and so I, I, I've got an anecdotal story here as well. When COVID happened and I couldn't go to the snow, I bought some rollerblades and I hadn't rollerbladed since I was a kid, but I was gonna do it and, and, and use it for sort of some ski-type training and test some things out. Now the, the rollerblades, when I first tried them, just going around and I was doing turns and, and I videoed myself And I looked at them and I went, wow, I've got this really crazy A-frame in my legs, and I'm pretty sure I'm going fast enough and doing all the right things. I was really tipping my inside ankle like as much as I could to try and get the knees the same. Yeah, it's like, what's going on? Rip out the liner in these Rollerblades, look inside, there's this ginormous wedged heel lift inside this Rollerblade. So I know we're not talking— I mean, this sort of along the lines of the binding, uh, Delta. But it's— yeah, it's tipping, tipping. My, my heel is higher than my toe. Anyway, so I rip that out, put them back in, go around, feels drastically different. I can get in an athletic position that feels centered. Videoed it, and the A-frame is gone. Yeah, so I can tell you, like, that angle has a huge effect on how you sense your balance.

It has a huge effect. So the difficult thing about the question, to get back to what you asked me, is what do people do about it? You know, with, with a lot of modern skis, in any particular ski, you can't do much about it because the binding comes on the ski, the manufacturer has chosen the angle, and you're stuck. You're just stuck. I'm not going to advocate for doing anything about it because Anything we talk about, I'm going to say, is it— I'm not going to— from a safety standpoint, it's— I'm not going to be comfortable. Okay, but what you can do is learn that you can run experiments, you can use other skis, you can learn that I like a 4mm ramp, or when I got on this other ski and— or I should say a 4mm binding delta and then when I tested an Atomic, let's say, and it felt so much better, let's look at what are the differences in the skis, and was it really the ski or is it the binding delta? And if it's the binding delta, then as I shop for skis in the future, I know that Salomon makes a flat binding, I know that Marker makes a flat binding, and I want to set myself up to ski those bindings. Or I know that Head bindings, Head Tyrolia, are— most of them are 4mm delta, but they make a race binding, and there's no reason a recreational skier can't use a race binding. And the race binding is adjustable any delta you want. Any good ski shop that sells that bindings knows how to get the shims to make it any delta you want. You can go get that binding on a ski and run your own experiments and teach yourself the whole program. Absolutely. So that's why I think it's important, just so people start to understand that when they get on a ski they really like— a lot of people don't have the luxury to demo a ski. If you demo a ski and you go, "I like this ski," okay, fair enough, you like it, buy it and go ski it. But a lot of times you walk into a shop and someone says, "This is a great ski," and so you go out and ski it, and then and then you think, no, this isn't a great ski. But it might be a great ski, except the binding is in a different place or the binding belt is different. And if you learn about this stuff, you can start to understand the differences and how you can correct them. Yeah, absolutely.

Yeah, I would say, like, I've had quite a lot of, uh, the Big Picture Skiing followers who've seen that podcast with you they've reported trying to change— well, we're talking about the fore and aft thing, but, but that's also a big effect, changing that.

And, and just skiing was easy. This episode is sponsored by Carv, the digital ski coach, and one of the updates I've really enjoyed this season is the addition of separate SkiIQs for moguls and short turns. In the past, Carv scoring was mainly built around carving metrics, which meant everything was viewed through that lens. But Carv have gone deep on that research and completely separated what makes a great short turn or mogul turn different from a carved turn. To give you an idea of how accurate it's become, the person at the top of the Carv leaderboard right now isn't a carving specialist, it's Olympic mogul skier Matt Graham. So the best SkiIQ in the world at the moment is coming from someone who lives and breathes bumps. And to be honest, my own highest SkiIQ is also in the moguls. Which makes sense because that's my favorite type of skiing. What's really exciting this year is the addition of Turn Tempo, so basically your turns per minute. It's such a simple external output that's incredibly fun to play with. So good skiing isn't just about edge similarity or parallel skis, it's about how you interact with the terrain and whether you can change your tempo on demand. So seeing numbers like my quickest tempo of 117 turns per minute in the bumps gives you something concrete to compare, refine, and work toward. I've been working with Carv since 2020, and every year I'm genuinely impressed with how much the product evolves. They keep expanding what you can measure, and they're covering more and more of the turn types that skiers actually use all over the mountain. So if you're interested in tracking not just your carving but every turn you make on the snow, check out Carv. And a big thanks to the team for supporting this episode.

Yeah, um, and like, it's a difference of, you know, 5 millimeters, 10 millimeters, a centimeter, and, and they found it was just easier to make turns. Now I think we should talk about, like, so, so with this binding, uh, Delta. Yeah. Uh, what are the felt sensations some would experience when they have a flatter ski? So back to that story of the young kid. What did they perhaps see that they're like, he is skiing better now?

Okay, so we're talking about high-performance carving skiers now, right? So the difference for most people on a flatter binding delta is that what I've found with my customers over the years and with a lot of— and with racers is that with a flatter binding it is easier to stay forward. Okay, and that as soon as you're on an angle, you automatically— it moves your hips backwards and you start to sit back. Now we can talk about whether that's because of the mechanics of being at an angle, or it's because as you're at an angle and you lean forward, you feel like you're going to fall on your face. But, but so what happens is you can't get pressure to the tip of the ski as easily. So, so the subtle difference for a performance skier is that, is I find that on flatter bindings, the tip picks up the top of the turn faster and the ski just feels more responsive, immediately more responsive. Not in a, oh my God, I can't ski the other way way, but in a, oh, this is just nice. Look, I just I've been working on this for a long time, and here, here it is, here it is. Yeah, yeah. And my ski just feels more responsive.

Yeah, I would agree that that's what you found. Yeah, that's, that's what I found too. And I, and I think that, that sort of the, the ramp, the— sorry, the delta, and also the moving the, the binding forward and back, like moving a binding forward, obviously you're going to be closer to the tip, same thing as well. They, they have the same kind of effect in terms of the tip engagement. And I guess an anecdotal, uh, story again why I'm moving my slalom skis— I want to move them back again now— is because I'm finding whatever I'm doing, that tip is hooking up almost too much and turning into me and closing the turn shape off perhaps sooner than I would like. But I think possible. Yeah, yeah, yeah.

And but, but I think it's awesome. Go ahead. Everybody has to do their own thing, right? There's no, there's no like, here's where— that's what we're talked about. There's no mark on this. There is a mark on the ski, but to think that that mark on the ski is the right place for everybody is just flagrantly wrong. And, um, and to think that you can't change binding delta and there's no effect is also flagrantly wrong. And you can get subtle differences or great big differences. Yeah, I think it's a great opportunity for, for learning.

Like, that's what I would say I'm taking away from it. It's like, I experienced how much that tip engaged and what it did through a bit of like mechanical aiding with the, with the, with the binding change. And so now I've learned that I can come back. So for someone, could be something great to try to actually learn to feel something with the tip at the top of the turn.

Exactly. I mean, what I think is— it's the same thing, I'll just reiterate— is that there's a lot to ski setup that we don't understand. And every time we go out and ski another ski and either like it or don't like it, it may not have anything to do with the ski at all, and it has everything to do with the way the manufacturer chose to set the ski up. And we can change it and There's just all kinds of stuff you can do with your gear to make it work better for you. Yeah. And to make you better too.

Yes. Now I think it's important here, Lou, because, uh, if people are clever and they know a bit about maths, they'll have seen that, you know, you just measured the toe and the height, and then, you know, like, there's this difference of whatever it is, say 6 millimeters. But there's also another factor here, and that is the length of the distance between those two heights. Right. And so, so shorter, obviously closer together, that's going to end up being a steeper delta angle than a further apart distance of 6 millimeters.

That's right. And that's why— go ahead.

I was just going to say, yeah, speak to that because I think the next factor people want to realize is it's relative to your foot size, right?

So, and that's exactly right. And that first, that's why when we talk about it in a shop, we don't talk about an angle because I don't know the angle. It's different for every boot in every binding, and it's like, it's just too much to keep up here. So if I know that a binding is 4mm, let's say, and I know in my experience that 4mm at a size 24 boot, nobody's happy with it. Or everyone's hat, whatever, then I can start to decide whether it's a problem or not. Right. So I don't try and go by, oh, it's 1.5 and 4mm at 272 is 1.8. So it's too much to do. Right. So that's why we talk about it. But it is the reason that women have more issues with these kinds of things than men do. And not because women are weaker or anything, it's because their feet are shorter. So all the things we talk about are more pronounced for women because the angles increase.

Absolutely, yes.

And for kids. I mean, this kid is in the same size boot as an adult woman. He's in a 24. So angle, it's 6mm delta. The angle is steep for him. Yeah, it's a lot to stand on.

Yeah, absolutely. Now, uh, if we look at also the effect of that 6mm difference, or like steeper delta angle, do you want to show the liner or the boot and how it's not only sort of changing that, that sort of like where you're balancing to, to, to, to get forward, but, but that that whole cuff angle, the— Right. In some—

Forward lean. Well, let's do it this way. I mean, what it does is it tips the boot like that, right? Let me lower it. Tips the boot like that. So you can see the spoiler is moving forward. So what it does is not only stands our foot on a tilted surface, but it brings the whole cuff of the boot forward. So it's pushing our tibia forward. Right? So it's changed the effective forward lean. It's automatically increased the flexion angle at our knee. If we're going to stand in the same position, it's pushed our tibia forward. Now our quads are working harder. Everything just gets— all the problems get ramped up. And I don't want to presume it'll be different for everyone, but whether the problem is more this or that, it doesn't matter. When it's binding delta, both things are happening at the same time.

Yeah, and I thought you brought up a really interesting point there about like, you know, so many people are like, you know, it's all about getting the shin on the front of the tongue and pressure there. Right. And do you want to lift the boot up again and just point out like, that tibia is getting pushed forward from the back, right? Which means the front— now if you look at the tongue, it has moved further away from the tibia. So now the tibia— yeah, so the tibia has to go even further forward to engage. If people are trying to do that with it, there's going to be a problem. Yeah, that's right.

So you have to either exaggerate how far forward you bring your upper body, and when you're standing at a really steep angle on your foot when you get your upper body that far forward, you feel like you're going to fall on your face. So you automatically bring yourself back. But the other thing that happens is you've moved the, uh, the tongue away from your tibia. So that means you need a lot more ankle flexion before you can bring your tibia back. So you, so you close your, you close your foot down, right? And you get— so you're skiing with more ankle flexion and more knee flexion. It's just hard, you know. It's a compounding mess of things that you can't teach away. And if the problem— and I'm sure you've experienced it, I see it all the time in the store— is someone comes in and they say, I can hardly ski 5 turns and my legs are just wiped. And almost always It's a problem with these angles, right? And the easy place to start is binding delta. Yeah. And maybe it's fixable on the skis they own, oftentimes not, but if it is, fix it on the skis they own. If it's not, you're going ski shopping. But the results are dramatic, right? You can change it so that someone goes from not being able to ski easily to actually spending the day out on the hill. Yeah, yeah, great.

So I would say if we sort of summarize that, people, start just, just measure your own setup, find out, maybe measure, you know, say you have 3 pairs of skis, measure all the bindings, the, the delta there, and think which ones do I like for particular conditions? Do I like these ones in bumps? Do I like this one for carving? Whatever it is, and just see if there's any relationship there with, with flatter or, or more ramp. I think that would be the first stage. And then, you know, then you can go out and try and experiment, right? Test, test other skis that have different ramp angles, uh, delta angles, sorry, and see what you like.

And you may advocate something different, but, but I would advocate for trying to ski on the same binding delta all the time because I think—

definitely.

The one thing you want to do is be able to stand the same all the time and not have to— not get on the ski and have to figure out, okay, what position do I need to be in? So if I like a flat binding, I try to have it. It doesn't matter to me if it's powder ski or bump ski or what I'm doing, I want flat bindings all the time. So in my store, we tried to set up every ski the same. That's hard to do. But that was a goal. Yeah. And it's why we worked as much as we could with flat skis. So if someone came in— this is a funny way to talk— but if someone came in and as they walked in the door, I started thinking, oh, this is going to be hard, you know, and I'm starting to picture what are the problems I'm going to have. I'm 5'3". And, and I can see that, that you've got really big calves, right? And a woman that's 5'3" does not have a very long tibia, so I know her calf is inside the boot. So before we even get started, I'm already sorting through the decisions I have to make on complete equipment setup, right? And if we're going to look at skis, we're going to look at a flat ski so that I can pick a binding that I know I can make work.

Yeah, yeah, nice. Cool, perfect. I mean, I think that's— that was a— that was a— that was why you reached out. You're wanting to help get this message out, and I think it was great, especially the timing of the, the story with the boy, the, the German Shepherd puppy, uh, changing from Rosie to Atomic, and you going, I don't know if it's so much of this magic Atomic stuff, there's something else. But We've been able to now share some, some more information, some things to check with people. And yeah, it'd be great if we heard from people about this, uh, in the comments. Yeah, yeah, just some, some, some anecdotal evidence. Just what are they, what are they like, what do they find? And I'd be really interested too to hear anyone that really likes more, uh, delta and why and in what conditions. Because, um, yeah, we're not, we're not saying it's like flat is best and it's the only way. Just gives a certain result with how you interact with your skates. So, um, yeah, it'd be great to hear some people talk.

You know, I've closed my store in the last year, but, uh, but the website is still active, and people, I'm sure, are welcome to comment to you and ask questions. But if someone wants to contact me, I have no problem.

Yeah, can you, can you say what it is again, the website?

Well, the website is lous.ca, lous.ca, right? And I can be contacted here. It's so I could remember it. And they're welcome to send me questions there. And I'm not as fast as I used to be on it, but I'll get back to you in a day or two, probably.

That'd be wonderful. Well, Lou, thanks so much for coming on again and sharing your knowledge with everybody. And yeah, have a great summer. Hopefully we still get to have that those, those turns on snow one day.

Well, that would be really nice. I'm, I'm, I mean, this, this rotator cuff tear has changed my whole summer. I wasn't necessarily going to be in New Zealand, but I was thought maybe I'd be in New Zealand or Australia, and now there's not a chance I'm skiing, period. So yeah, we'll just have to wait.

Good. Well, happy, happy healing. Good luck with that. Thank you. Let's Let's stay in touch.

Okay, see you again. Thanks, Tom.

This episode is sponsored by Carv, the digital ski coach. And one of the updates I've really enjoyed this season is the addition of separate SkiIQs for moguls and short turns. In the past, Carv scoring was mainly built around carving metrics, which meant everything was viewed through that lens. But Carv have gone deep on that research and completely separated what makes a great short turn or mogul turn different from a carved turn. To give you an idea of how accurate it's become, the person at the top of the Carv leaderboard right now isn't a carving specialist, it's Olympic mogul skier Matt Graham. So the best SkiIQ in the world at the moment is coming from someone who lives and breathes bumps. And to be honest, my own highest SkiIQ is also in the moguls. Which makes sense because that's my favorite type of skiing. What's really exciting this year is the addition of Turn Tempo, so basically your turns per minute. It's such a simple external output that's incredibly fun to play with. So good skiing isn't just about edge similarity or parallel skis, it's about how you interact with the terrain and whether you can change your tempo on demand. So seeing numbers like my quickest tempo of 117 turns per minute in the bumps gives you something concrete to compare, refine, and work toward. I've been working with Carv since 2020, and every year I'm genuinely impressed with how much the product evolves. They keep expanding what you can measure, and they're covering more and more of the turn types that skiers actually use all over the mountain. So if you're interested in tracking not just your carving but every turn you make on the snow, check out Carv. And a big thanks to the team for supporting this episode.