johnasmo

Letting the calculator figure the radius is a good thing. Calculating radius from sidecut depth and effective edge is a good way to take the sidecut shape out of the picture. A VSR shape and a radial shape with the same depth will project to a plane with a similar curve depth, but the shape of the projection will differ, making that a design variable you can play around with. A turn size calculator that doesn't take into account snow compaction won't be able to explain how straight skis turn. Trench depth matters, but predicting it with a calculator would involve knowing rider mass, speed, and some tangible measure of compactability as a function of depth. Yeah, that's when the math and physics get so complicated that making and testing prototypes remains more practical. A calculator that took trench depth and board angle as input, though, could calculate your turn size without even knowing sidecut radius. It's always going to be about both flex and sidecut. My feeling is that sidecut radius is a good predictor on firm hardpack so long as the board isn't too stiff. In softer snow, say leaving two or more inches of trench, it's more about the flex. And like sidecuts, different core profiles produce different flex patterns, making that a design variable you can play around with.

It seems worth mentioning that both splay and canting change with stance width and binding angles. At lowest angles and wide stance, it's common to have 20 or more degrees of splay. The 5 degree rule of thumb seems a throwback to when 50 to 60 degree posi-posi angles where the alpine norm. By the time you get to 70 and up on a Skwal, you may end up with negative splay. It's simply biomechanics. Here's an illustration. Stand facing a wall with your feet 20 inches apart with whatever splay feels natural. Note the splay. Without repositioning your feet, rotate 60 degrees, feet included to a natural splay. Now step your rear foot straight forward from where it is. Your feet will be near shoulder width apart. Again note the splay. It will probably be more like 5 degrees. The same plays out for canting to. Low duck angles and it can be all inward canting. Around 60 or 65 it can be all lift. At 75 and up you could find you need some outward canting. It makes no sense to stick with one number for either splay or canting (or angles) when changing the other variables in the physical equation. Solve for each board width and stance. IMO, under-hang blows unless you are in soft snow where you can get some support from the base somewhere under foot.

Whitefish and Schweitzer are the bigger, taller plays. Whitefish tops out at 6800', Schweitzer at 6400'. Both are similar size and have similar show depths right now (60+" summit, 20+" base). Enough to survive the rain. Lookout Pass is about a third the size and half the vertical, but usually gets plenty of snow. However, it tops out at 5650'. Snow depths are 46" and 18". Silver falls between. It is about half the size of the big boys, but similar vertical and good enough summit depth (50+"). Buddy passes at Whitefish are $62. Each passholder gets a few. If you are diverting to Whitefish, let me know. We may be able to find remaining buddy passes. If you want to road trip to even higher elevations, options are Lake Louise or Sunshine Village in Canada, both about 5 hours from Kalispell, and Big Sky about 6 hours south east. Schweitzer, Lake Louise, Sunshine Village, and Big Sky are on IKON pass if you have one.

Wasn't expecting colder again. I'll be closer to 11 I think. We're colder than Revelstoke, again.

Ed's was good carving on Sunday. Upper mountain should be back open Monday. Will still be cold until Tuesday.

Sorry to say that the wood core is most likely damaged. You could get cartwheeled when it folds for good. Be careful with that one.

I bet it would be easier to talk Bruce into building a true twin tip than into building a swallowtail. I can see it being a hassle to deal with the edges on that. @dredmanchatted with Sean Martin and Ryan Knapton last spring about building a Donek Knapton Twin with a Contra sidecut. The Knapton Twins are radial right now. Sean already has the worksheet for doing the new "Turner" alpine model, and it would be super easy for him to mirror the shaping parameters front and back and have a true twin tip. That's exactly what was talked about, but I don't think he ever got around to building a prototype.

Unfortunate indeed. He used an ultrasound to position the injection, but I think a nurse assisting might have done the injecting. I wish I'd paid closer attention to that. I wasn't expecting a problem at that point. The outside of the foot, the area forward of a diagonal from the outside of the heal across to the big toe, has the worst numbness. The forefoot has a constant sensation of pressure, like it's being squeezed. Curling the toes down causes this feeling to exaggerate in the bottom of the forefoot. Sort of like the skin is hard and is being crinkled up. I'm hoping for continued re-innervation, but it's been 6 months already and there hasn't been much improvement to sensation. I guess it'll be like tinnitus... just gotta learn to live with it.

Yes, tip to tail. Sharing the full details of your sidecut here. There are a number of control points with parameterized relationships to one another as well as to effective length and setback and stance positions. The specific parameters of those relationships define the overall shape of a model. The control points are then navigated using constant acceleration or deceleration of curvature. That makes for a continuously changing radius with no abrupt changes to curvature. Then the shape is scaled so the sidecut depth matches a "radial equivalent" depth of desired radius. I think sidecut depth equivalence is a better predictor of how it will feel than average radius. The Contra shape already goes to longer radius at the ends, but well short of becoming straight, and thus far not parametrically integrated with the tip and tail de-camber of "early rise" core profiles. Unless the builder sands back the sidecut as part of blending to the nose and tail shapes, there could be sidecut curvature all the way to the end of the effective edge. But if the base has already transitioned from camber to rocker by then, there's no need to add any sidecut-induced flex and little ability to anyway since there's no further edge contact to lever against. My thinking is that being straight there would better spread the edge pressure back from the very end of the effective, making it grab and seek less. You're build, with the more gradual drawn out nose decamber, sort of points in that direction. The effect of the "low-rise" rocker should be more noticeable than what I'm proposing anyway. What happens to the sidecut in the first or last 150 mm of the effective isn't of much consequence compared to the shape of the rocker in that area. I just like to make the math elegant. That said, the longer these drawn out noses and tails get, the more the effect on the sidecut should be considered. I've already got decamber compensation control points in my design worksheet. Just waiting for a build that needs them. I could even inflect the sidecut curvature past straight into the other direction to make a big floaty nose like on a Jones Mind Expander. Any takers?

Did someone say Sidecut formulae? That's right up my alley. Are you shaping a custom sidecut profile? Or aiming for a given turn size? Turn size can be tricky, as there's more contributing to it than sidecut. Flexing a sidecut profile to meet a plane is part of what induces flex in a ski or board, but there's also flex coming from snow compaction. That's how straight skis worked for so long -- turny in soft-ish snow, not so much when not. And though sidecut depth is a good way to map a sidecut profile to a radial equivalent radius value, modern boards and skis are seldom radial. Then there's the stiffness of the flex having as big or bigger impact on the turns than the sidecut. Are you building your own skis and looking for CNC toolpath help, or just spec-ing a custom build with someone? I think the outcomes can be better starting with a known build that you've ridden and say how you want it to behave differently than to pick a number out of the blue.

Well, it's been over 6 month now and I'm about ready to share the results of my surgery. I was meaning to post sooner, like all summer long, but every time I thought about it, I just didn't want to... think about it. Lesson learned: Beware of nerve blocks! My ankle surgery (tiliofibular syndesmois fixation and deltoid ligament repair) went well according to the surgeon, but the outcome was doomed even before I entered the operating room. The anesthesiologist did two nerve blocks and caused damage to branches of the sciatic nerve. It took 72 hours for one of the blocks to wear off and I haven't had normal sensation or strength in the foot since. I'm now holding out hope that by this time NEXT year it will be feeling more normal - less like a numb, foreign body. Damage confirmed by electromyography (EMG) which showed, "reduced Tibial AH and Peroneal EDB motor amplitudes, as well as absent sural and peroneal sensory responses." The impaired signals start above the knee in the vicinity of one of the nerve blocks. A followup MRI showed, "increased size intrasubstance signal involving the common fibular and tibial nerves...." So pretty sure I got jabbed and injected too close to the nerves. Opps, his bad. I spent my summer doing PT. Short hikes. Even shorter runs. Strength is up to 60 or 70 percent, but endurance is low. The foot is good for maybe 5 miles of hiking and only 3 of running before it poops out. Calf gets sore; pry from the muscle fibers that ARE still innervated carrying for the less innervated ones. On top of that was three broken ribs, lacerated spleen, and slight pneumothorax in September, but that's another story. I've put that behind me. I'll find out how the foot fairs snowboarding when the local hill opens in a week and a half. No hiking runs yet as the resort is still waiting for snow. It should be strong enough, as it's just lower leg. Toe/heal strength on softies will suffer, but not so much up/down of alpine. I am worried about how the numbness will impact my feel for the board and snow, though. And the cold could make the numbness even worse, turning it (literally) into a pain. I have a box of charcoal toe warmers waiting.

I've been trying to convince Bruce to let me transition the sidecut to straight by the time the camber switches to rocker, but he's hesitant to let me bake that into the sidecut templates. He does a few different lengths from each template. Maybe someone needs to specifically order one that way? I thought 16 was crazy for anyone whose name isn't James. Glad it's working for you. It's basically a Contra-BX 16, which under closer examination is a 18.5 - 13.9 - 16.9 - 15.8 - 21. He's built a lot of that shape for Korean riders, but thus far only up to 14m.

More the later than the former. A Contra by any other name would ride as sweet. I helped Sean to incorporate a version of the curvature accelerations and decelerations that make up a Contra shape into his build process. Then we iterated builds providing feedback on flex until we found the sweet spot for Sean's proprietary core shaping math and lamination. It fits into the lineup as an all new board; like no other Donek before it, but targeting the "freecarve" segment of the lineup. Mild vs. spicy is about damping, not speed. Spicy (standard construction) rebounds like glass, mild (secret construction) rebounds more like metal, although it is not metal. What makes it friendly to beginners and advanced riders alike is the confident feedback and exceptional edge hold. Confidence for beginners and intermediates to go faster and lower and advanced riders to go steeper and narrower. I only had a chance to ride the final design in the "spicy" construction before I blew up my leg/ankle last spring (on a different board). On a crisp spring morning, my impression was, "OMG, this thing is grippy and lively and fast; it's ready now." Looking forward to hearing feedback besides Dave and I.

After a summer of physical therapy, I finally get back on the forums to whine and lament my post-operatives woes on the "AIL "Alpine Injured List" thread, and the first thing I read is this. Now my problems don't seem so serious. I still plan to whine about them, but now I'll wait another week so as not to be feel embarrassed doing so. There nothing I can say to take the edge off a bummer outcome; you have my best wishes, for what that's worth. You're a fighter, keep fighting. Snowboarding is such as small thing when faced with stuff like this. I know someone in Whitefish who lost their bladder to bladder cancer, but they had Neobladder reconstruction afterwards -- constructing an artificial bladder from intestine material. I suppose after 8 surgeries that option may have already passed, but if not, ask your doctors about it. It is not snake oil. https://www.mayoclinic.org/tests-procedures/neobladder-reconstruction/about/pac-20385066

Troy @b0ardski, 11 screws and 2 plates and you still had the option of non-surgical? Bet it would have looked like a mountain range on your shoulder. Hope it heals well. Clavical was my first ortho surgery after moving to Montana 18 years ago. Also my second to remove the hardware. Only 10 screws and one plate, though. Next week will be my 5th. Mountain life.

Second opinion always a good idea before taking the option of last resort. Update: Second opinion received, this time meeting with an actual surgeon at a different clinic. Same diagnosis and treatment recommendation. Both argued that when tibiofibular syndesmosis injuries are left untreated it can lead to chronic ankle instability and degenerative arthritis. Both felt there was evidence of enough syndesmosis injury to warrant internal fixation to put things in the right place to heal properly. They'll look for other ligaments needing repair while in there. Rather than wait 6 weeks to see if it's still messed up, I'm going to do the repair and hope to be on my feet again without a boot by June.

At a macro level, we have a chairlift loading us up with potential energy that we then convert to kinetic energy and friction in delightful ways until we're back to where we started. At the micro level, though, there's rollers and pumping and another energy source, our bodies. Sucking up on the approach can prevent converting kinetic energy back to potential energy; extending at the top can inject your energy as potential energy into the system; pumping a transition can convert your energy to kinetic energy. Being tall at the top of a roller doesn't necessarily translate to more kinetic energy (speed) out the bottom unless your able to convert that potential energy to kinetic energy in the right direction, forward. You need down force against the slope for that to happen. Maybe better to say, be as high as you can to still pump the transition. Which still might mean sucking up the approach and waiting to push out against the transition in short, steep rollers. On longer rollers, though, you can still get up high and then fall into pumping the transition with that much more energy added. This video on pinewood derby strategies illustrates that importance of adding potential energy if you can.

Good news is no posts to this thread since December 30th. Bad news is that ends today. Season ended for me March 27th. Solo carving. Got tossed in a toe side resulting in a oblique proximal fibula fracture, minimally displaced. I.e., an angled break above the boot cuff. I waited to post until seeing an ortho as that wasn't going to be the full story. I saw ortho's PA today and they basically ignored the fibula fracture as uninteresting (didn't even take a new x-ray) and turned to the ankle. They diagnosed a distal tibiofibular syndesmosis, where the fibula and tibia get separated at the ankle. They say it needs anatomical reduction (via surgery) or the biomechanics of the ankle will be messed up leading to arthritis. This won't be first surgery for this ankle; I had a flap of torn cartilage removed from the talus in 2011. Yes, it hurts. Still swollen and ugly a week later. Hope to be recovered by summer. Stay safe out there.

That's my shell size. Riding UPZ RC12 now, but have my old UPZ RC10 shells for backup. Maybe we can arrange a demo day. The boot mold is still the same; just different tongue attachment and buckles. I stuff size 10 liners in them from the next size up, so still have the original size 9.5 liners unused.

There are no shops renting alpine setups anymore. AFAIK, there are no shops in Montana even selling any. It's all online shopping. The Montucky Clear Cut held at Turner is an opportunity to demo boards, but still BYO boots and bindings. For safety, steer clear of antique gear. In the last decade, there aren't as many choices as you'd think for boots and bindings. For boots it is just UPZ and Deluxe really. Mountain Slope is too $$$ to just test the waters. For bindings it is Bomber or F2. You can find used on the for sale forum or eBay, or you might luck out and be able to borrow something. What size boots do you wear?

Will a dedicated dedicated carving board make a difference in terms of making carving turns? Yes. What is a dedicated carving board? Need I remind everyone that this is an alpine snowboarding forum? Let's just say there's an easy way and hard way to approach carving. The physics and physiology of carving favor steeper binding angles. Steeper binding angles favor narrower boards. You can see where this is going...

You have the right idea, getting the board higher on edge, getting your center of mass on the upside of the board perpendicular, and driving the knees down. Lots of people say drive your knees, but what does it mean to drive your knees? How do you do it? Use the The Skeleton Dance to sort it out. Dem bones, dem bones, dem dancing bones. The leg bone's connected to the knee bone. The knee bone's connected to the thigh bone. The thigh bone's connected to the hip bone. Think of it like as using your thigh bones (femurs) to drive your knees to the snow. To do that, you need to position your hips behind them, even on heal side. Rotate your hips to make it feel like your are pointing your femurs to the snow and then let them drive your knees down. Keep your shoulders relatively level and don't reach for the snow and, voila, you will find yourself angulating more than ever. Unless you are on a Skwal, you probably won't be pointing your femurs down on heal side, but try it as a drill before you discount it. If your butt is out beyond the heal edge, your center of mass will likely be in the wrong place at the wrong time. Treating your femurs like the tiller of a boat will help you swing your butt where it belongs. There's a reason euro extreme carvers are always talking about rotation. Physics and physiology at work.

Coiler stiffness decoded. Bigger number is stiffer, but numbers are only comparable for same length, camber, lamination, and rocker profile. They are not some kind of linear stiffness scale per se. X . Y + Z X.Y is a measure of deflection in centimeters (e.g., 6.0 or 6.6, etc.), but it's 12 minus the board deflection. The number is the distance from a flat surface to the board suspended at the ends of its effective edge on 12cm blocks when under about a 75 lbs weight. I.e., suspend the board, put fixed weight on it, precisely measure distance from the surface to the board. + Z is a record of the nose decamber profile used, as that will affect the X.Y measurement. His build sheets include such measurements of the blank core, after initial lamination, and after topsheet. The numbers are a simple and precise measurement for quality control purposes. He'll know a target number he wants to hit for a customer based on his experience with that customer and their other boards. Start with a precisely milled core; thickness chosen to target the flex he wants. Measure the blank core stiffness to fine tune the laminates needed to hit the target. Measure again after laminiation and add or remove glass/carbon until that's on target. Then the topsheet goes on and final measurement is taken for the records. Hand made craftsmanship. When someone says stiffer or softer than my or so-and-so's such-and-such build, that's where these numbers come into play. Given 3 points on a curve, you can compute a decambered radius, and in theory have a normalized stiffness measurement for all your builds. Yes, I've done that. However, this is just a static deflection, and the laminate choices like T3 vs. T4, ratio of carbon to glass, and type of glass affect the dynamic feel of the flex. IMHO, seat-of-the-pants is the best way to judge board stiffness. Get out and ride them to establish a pecking order.

That 194 has a 19 meter sidecut depth equivalent, so at least it doesn't get much wider than 210 anywhere else. The radius profile is here. My figures say the nose should be about 46mm wider than the waist. In contrast, a 11.5 meter Contra AC 173 spreads by 59mm before joining with the tip, so the 194's nose will only be 7mm wider than a 19cm Contra AC 173. Fun with numbers.

I've seen a powder Skwal in action ( @skwalguy); Lacroix actually made powder-specifc Skwals. Alpine boards off-piste is not my scene though. I don't ride the same board (or boots) I carve corduroy on when there's 20cm of fresh. That's why we have quivers. 65/60 or thereabouts to carve, hang ten at 15/-3 to surf. Treat yourself to a narrow board if you want to expand your snowboarding horizons, but don't expect to settle on it as a quiver of one. I have a 14.5cm Coiler Skinny, but it's not my daily driver. Year's ago, it was on a Donek VladCrv 17cm that carving started to click for me. Riding high binding angles helps you break free of the physical habits learned from soft booting at low angles. There's more to alpine snowboarding that just snowboarding with plate bindings and hard boots; skinny boards with high angles helps you see the light. Go skinny to expand your breadth.