johnasmo

Yeah, no. Not this time. The Flat Earthers are getting people killed this time. Maybe the analogy was too subtle...

Lots of talk about sidecuts in this thread, but little about flex. If you're not ordering a custom board, you better pay more attention to flex and suggested rider weight. Sidecut is not like a dial where you can turn up and down turn size and speed; there's more to it than that. From my experience, flex is a stronger determinant of turn size and speed than sidecut. A stiff board with a tight sidecut will still run fast and big in soft snow. A soft board with a long sidecut will still run slow and tight in soft snow. It's only on icy or very firm hardpack where you will notice them fighting each other if they are not well matched to the speed you are trying to go. And in the end, flex will win out as the stronger determinant. It's natural to think of sidecut as what you choose first, as if it's driving the bus, but it's only one of several factors influencing the deformed shape of the board as it carves. It might be more useful to see sidecut as an output rather than an input. I.e. Something calculated to balance the flexing forces against the board's stiffness using the traction from penetration and compaction of the snow to achieve the flexed shape a given speed and turn size requires. Generally it will be true that stiff and straight will turn big and fast while soft and tight will turn slow and small, but there's a lot of leeway to be creative tuning the sidecut to taste since the stiffness is the stronger determinant of turn size for a given speed.

Day 2 drop. A few more people on Saturday (see 3:55). Still, without a pond skim and live music, fewer than most years. I liked it better this way.

Carving is my happy place.

Traction where it's needed, without unnecessary rider isolation. Never rode one, but that's my guess. I kicked the bees nest with my first post on page one of this thread, where I summarized my design thinking as: "As I see it, sidecut shape, along with snow compaction or lack thereof, plays a role in influencing the shape it is being flexed into. The board's resistance to being flexed into this shape affects the pressure distribution along the base. How well the pressure distribution matches available friction along the edge affects edge hold. Available friction along the edge is a function of downforce and tilt. " We got sidetracked onto sidecut size issues, but let me take this opportunity to return to the issue of sidecut shapes. A board that turns most aggressively near the tip requires traction there to match. Tilted to 90 degrees, the lateral stiffness of the board would distribute the rider's down force (vertical pressure) all the way out there without loss. But at lesser tilt, say under 45 degrees, it's being distributed through a platform that has longitudinal flex. The tip can be flexed (and twisted) away, leaving the rider's vertical pressure closer to its input locations on the board -- where the rider's legs are attached. If there's not enough vertical pressure where the turning loads are greatest, the horizontal component of the centripetal forces of turning can overcome the available traction. Adding a structure between the rider and the board changes where the vertical pressure is applied to the board. By the looks of the Allflex designs, going from two contact points to three and widening the rider's platform by about 300mm. So it's a structure helping distribute the input of the riders weight closer to the tip and tail, which should be useful to increase traction at the tip and tail if that's there the board needs it. I believe most plates have a similar effect, but the brilliance of Allflex is that it doesn't pursue trying to isolate the board from the rider's input. The whole "letting the board flex naturally" idea. The rider is the pilot; their inputs should be useful to control the board, including its flex. A good plate should be giving them more control, not less. The Contra designs go a different way, a contrarian way. Instead of playing tricks (camber, plates, torsion) to redistribute traction to where your tires are, why not move your tires closer to where the traction naturally is? I.e. Use sidecut shape to affect where load is being borne against the snow to keep it closer to your legs. Plates also allow for tuning aspects of the board's stiffness and torsion to suit the rider, but at twice the cost of the boards I buy, there is an alternative -- find someone that can make you custom boards that cost less than these plates. It's quicker and easier to hop on a different board than to re-tune a plate throughout the day.

Just my bad form. Hesitation to throw my body downhill early when not carrying enough speed off the last turn. Side effect of completing turns too far, taking too long in transition.

@crackaddictis correct. I retract my statement that they are the same indicator geometrically because depth gives you a single number that is affected by both length and radius rather than just radius. It contains more information than just radius alone. But if you do have values for both radius and length, discard depth altogether, it does not add more information. If you know only radius and depth, but not length, use depth as the better predictor when comparing two boards. We usually know both length and radius, so this is somewhat academic. Even knowing length and radius you can't accurately predict turn size without knowing something about the stiffness of the board, but we lack a standard quantitative measure for that. As tilt increases, the influence of stiffness on turn shape surpasses that of sidecut radius. IMO, radius predicts how turn initiation feels, how quickly the board begins to steer underneath to keep you from falling into a turn as your roll it on edge, but flex quickly takes over the main role if the board can penetrate the surface. Even straight skies can turn in soft snow. GS-like stiffness produces a GS-like turn size, regardless of sidecut radius/depth. One of the Coiler prototypes we just tried at Big Sky bears this out. It paired a long effective with a short radius and a go-fast flex. It's was super fun, but you'd swear it was 3 meters straighter than it is. A previous iteration (same radius) that was kept softer rides like a slalom board.

Yes, exactly. They explain how they don't want the ski to twist enough to change the direction of carving, but they acknowledge too much TR is a problem for how the ski tracks. If you don't allow some twist at the tip, all the forces must be dealt with longitudinally, and that adds more bounce to the nose. So TR is a variable to be used in tuning the front suspension. Too little is bad, but so is too much. I feel the right reason to use a plate should not be because the board is too harsh to ride otherwise. It should be to isolate the board from your bad behavior/inputs so it can win a race, not to isolate you from the board's bad behavior. If a board behaves badly, change it.

Yeah, no. Sidecut depth is a geometric result of the radius. The sidecut depth can't be a better predictor of turn size than radius since it's the same predictor. It describes the same thing about the geometry of the sidecut. But is it a good predictor of turn side? Sidecut acts as a flex inducer, so it can't be viewed in isolation from stiffness when it comes to predicting turn size. At low tilt (hence low flex), it's the majority predictor; as tilt increases, stiffness has an increasing say in the turn size. James is a rock star strong rider. He's going to be high on edge and pushing the board to its flex limits. Depth to him probably acts more like a backstop to flex than a flex inducer. So he can look a depth and know something about how hard he can turn the board without being told what radius it is. With the variable sidecuts I design, I boil the radius down to a, "radial depth equivalent." The sidecut may be a long-tight-med-tight-long progression of some kind, but then how to describe it in terms people can extrapolate from prior experience? By describing it relative to a radial sidecut. But rather than average the radii in the progression, I beleive (like James) that the best way is to describe it in terms of the resulting sidecut depth. So when you get a Contra 11.5m sidecut, the radius changes every inch along the effective edge, but the depth ends up matching that of a radial 11.5m.

I've thought about TR a lot. I find the torsional rigidity in the nose to be a big factor in how harsh a ride feels. The nose is the front suspension of the board and it can be tuned for the mix of performance and comfort that you are after. Back in 2015, I had a build done that had a big carbon butterfly under the base going from ahead of the front inserts to behind the rear. What was known as the Torsion Plus option from Bruce. In almost all other respects, it was to be like a previous build (a Nirvana precursor from 2011). I thought at the time that my mediocre skill level required every degree of edge angle the board could muster for better edge hold in icy conditions. What I found out was how high TR translated to being a harsh suspension. It cut slush like a knife, but was noticeably less comfortable otherwise, transmitting every irregularity in the snow to your feet, reducing confidence in hold rather than increasing it. It made the board feel wider because of it, even though it was same dimensions are predecessor. I feel the same harshness and width illusion whenever I demo a T4 metal board, including Bruce's T4 boards and my K168. They are super controlled, but the thicker titanal also increases TR and my legs feel it and my brain can't ignore it. Realizing what had happened, my next build in 2016, which I called the the Triple-X, suspended each section of the board (nose, mid, tail) independently. It used mini butterflies under each binding on the base, and then three independent carbon X's on the top. It proved quite smooth yet performant. But the X's were a hassle to layup, so it remains a one of a kind. I was happy with that board until jumping down the Contra rabbit hole in the 2018/2019 season. Today my builds keep the mini-butterflies underfoot and then just uni-directional fibers everywhere else. The full sheets of T3 give all the TR I want. Bruce has tried notching the titanal in the nose to relieve some TR in the tip, but I find that T3 doesn't need to be notched, at least not in the width boards I ride (<19cm). The profile with which the core thickness in the nose increases affects the distribution of torsional stiffness as that affects the cross section of this titanal beam, but that profile is being designed around the longitudinal flex for now. The effect on TR distribution comes along for the ride as the T3 is uniform throughout, but I've been really pleased with the shitty snow I can still enjoy on these. My philosophy is to design boards that don't need plates to be comfortable. Just say no to plates. Since I'm not a racer, I *will* sacrifice performance for comfort.

Don't ignore the optics and physics of what is going on with 360 cameras. There are two lenses capturing highly fish-eyed 180 degree views onto two sensors that are stitched together as a frame in the video. Say that image is a 5.7K image (5760 x 2880). Now you want to extract a portion of that image and render at least a VHD resolution image (1080x1920) that's not so fish-eyed. What are the chances that the portion of the frame you want has enough resolution for the quality you want, especially the further from the axis of each lens? There's a trade off between the ease of capturing with a 360 camera and actually pointing a lens at the subject you want. The trade off is image quality. Even with two sensors to capture 360 degree views, one sensor capturing just the field of view you actually want is likely to give you more resolution to work with.

No kickbacks. No special arrangement really. I ask for custom builds; Bruce is willing to build them. If he likes the result, he'll incorporate what we've learned into other builds. I spin our relationship as a design partnership, frankly to make myself sound more important. Bruce humors me by calling the builds prototypes and giving me a good deal, maybe even building a few variations to try out. But it's really the same relationship anyone could have with Bruce. It's the same as @Shred Gruumerspec-ing out custom builds. Doing the CNC programs perhaps takes it to another level, making it a more symbiotic relationship. I get that much more control over tweaking my boards, he gets someone to generate CNC toolpaths when he wants to use them for other peoples builds. So it's not a business relationship. It's all about the boards. I get to be a snowboard designer vicariously through Bruce; I value that. Bruce isn't trying to grow his business. Coiler is a one-man shop, and if anything he's looking to shrink the business or retire. I've shared this before, so it's no secret. It was inspired by my Thirst snowboards. I have an 8RW and a Superconductor. I observed they had better grip on icy conditions than I was experiencing from my latest Nirvana builds. But I liked the ride quality of my metal Coilers much more. I wanted to feel that kind of grip in a metal board. I could tell by looking at it that the 8RW had more of a long-short-long sidecut, and that it had freer center flex. I then formed hypothesis as to how such characteristics might contribute to better grip than my other boards, and created a sidecut and core profile of my own to test the hypothesis. A graph of the sidecut radii looked like a flying W, with a short-long-med VSR shape shrunk down and put between longer radii tip and tail. Now there have been a few iterations varying the shape of that W, with good results.

Ok, those terms may be better. But by downforce I meant only the vertical component of the pressure. By friction I meant the force that once exceeded by the horizontal component of the pressure leads to slipping. So static friction or traction.

Wow, I see I'm not the only armchair snowboard designer on the forum. Down the rabbit whole is right. I agree that a board's flex is the main thing in the end. As I see it, sidecut shape, along with snow compaction or lack thereof, plays a role in influencing the shape it is being flexed into. The board's resistance to being flexed into this shape affects the pressure distribution along the base. How well the pressure distribution matches available friction along the edge affects edge hold. Available friction along the edge is a function of downforce and tilt. The transition you mention above, the transition from flat to high on edge, affects downforce distribution. When running flat, the downforce producing friction is where the rider's weight is pressing down. The rest of the board can flex away. As it gets tilted on edge, the downforce gets more distributed because the board doesn't flex sideways. This shifting downforce is one the things I'm trying to account for, by getting the demand for friction to shift in a similar way along with it. My hypothesis is that you can use variations in sidecut radius to affect the distribution of load along the base. That load represents the demand for friction that needs to be satisfied at that location. How can sidecut affect load distribution? Sidecut and flex affect the shape that being flexed statically into the snow would like to form. Differences between that shape and the shape of the carve itself, the trench in the snow actually being followed by the board in motion, will cause some parts of the base to bear more load than others. So it's a design parameter you can play with to distribute load. The K168 makes a good case study for this transition from flat to high on edge. Some of its turns feel perfect. But it's a traditional high-camber, high-differential VSR. What I think makes it "demanding" to ride is that it demands to be kept high on edge -- to quickly transition from high to high. I think that's because having the tightest radii located at the ends of the tip and tail, that's where the demand for friction gets concentrated, but is only satisfied with downforce when the board is high on edge. At lower tilt, even with the high camber, there's a misalignment of the downforce with the need for traction and you get nose bounce. One of the reasons I think plates are so often used to help tame this shape even for recreational riding could be that it puts the downforce from the rider's weight onto the board further out than your feet. That may be helping get the downforce applied out closer to where it's demanded. With the Contra shapes, we're trying to make the load distribution (need for friction/traction) look like a bell curve that flattens out as you tilt higher to match up with the downforce distribution making the same transition. You shouldn't need a plate, at least not to help keep the nose loaded with downforce.

Observant. Yes, tip shape is different on that one. Bruce uses a plastic tip past the core and this one is 20mm longer with a different shape to it.

Very stable and very grippy. The result of incremental refinement, these protos are pretty good already. I think of these builds as 3rd generation Contras. Contras got their start as a custom build for me in the 2018/2019 season. To get the shape I wanted, Bruce let me do the math and create the CNC programs that cut it. Most 1st generation Contra’s out there are what I would call a Contra v4 (version 4). Version 1 (first build) proved that the Contra shape had good edge grip and could put it to use in lots of snow conditions. Version 1 worked well in shorter radiuses but felt slow to initiate turns in larger radiuses when not being laid over fast enough. Some examples of the tighter v1 are out there in the form of the 10.5m radius 166’s. Version 2 (second build) made some shape adjustments and accounted for radius and length non-linearly in the programming. That is, parameters of the shape itself would change based on target radius and effective edge and insert locations, not just be scaled up or down linearly. Versions 3 and 4 were roughly the same programs as v2 but with more elegant math producing the shape – from linear radius transitions to clothoid to polynomial curve fitting. Now I am using constant accelerations to rate of change, so could describe the radius transition curves between control points as clothoid anti-derivatives. The 2019/2020 season is when Bruce started making Contras for others, with positive feedback. I rode the heck out of the v1 and v2 builds I have. We also created some Contra variations for BX and FR soft booting, but very few boards got built. Changes were made to the parameters of the shape to account for the board generally not being tilted as high on edge, while softboot “carving” boards were still getting the alpine Contra shape. In the 2020/2021 season we got more feedback on the BXFR builds, and I got a K168 and liked it. Decoding the K168 inspired a 2nd generation Contra design to hybridize the high-differential VSR shape of the K-board with the Contra shape. Only a few of these exist. I have one, Dave has one. If you received a 10.8m Contra this season you might have one too. The Winterstick Montucky shape is on that spectrum. We got those early enough in the season to allow another late season design cycle. March thaw/freeze conditions are a good design crucible. I felt some characteristics got better and some not, so was inspired for a 3rd generation shape. That’s the Contra AC shape just prototyped. The Contra LS 185 proto is more related to v1, which worked well at allowing long effective edges to have short radiuses, but with characteristics from the next gen tail. Core profiles and laminates are also being refined. The protos came out a little stiffer than I expected but are so friendly to ride it just means going faster. The 173 feels very good; I think it will be a reference model going forward. Last chance to demo them will be at Big Sky this weekend.

Whitefish weekly rub-in. Sneaking in a final round of R&D before the season ends.

Final week for Big Sky. Should be half a dozen of us hardbooters there next weekend. Friday and Saturday for sure, maybe Sunday too. April 16, 17, 18. https://forums.alpinesnowboarder.com/topic/51458-closing-weekend-shenanigans-bigsky/

111 days lift assisted. 22 days skinning. And it's not over yet. Go West, young man. Really.

Bait and switch! The video is all from Big Ravine, but the thumbnails are from Toni and Corkscrew. I think the turn counts should only include the carves between the first and last knuckle draggers. The rest is just commuting to and from. That puts these counts in the 50's.

Take his website with a grain of salt. The sizes listed are like historical averages. Models too for that matter. He'll talk you into a Contra anyway. Just pick a radius and length.

Someone product-ized tooth cam! Remember the one I made from a $10 sport mouth guard and a 50 cent metal bracket back in 2009? Still keep it in the car in case I need a hands free without a full face helmet. Did some decent follow-cam with that thing 10 years ago at SES before I even had a GoPro: https://www.youtube.com/playlist?list=PL64D63458871D06C6

Metal at last, metal at last, TGA metal at last. Trading some lively for a bit of peace and quite is reasonable.

That looks all too familiar. Heavy spring snow dig and pop. Take the plate and screws out in the fall.

Sweet. Fun in the sun carving spring thaw. it looks steeper and faster if you watch it on your phone!