SunSurfer

Emi Sato was an active World Cup level racer for Japan till recently. FIS athlete profile says born 1990.

Single application bridging the teeth on the adjuster and the gap in which it rotates has held through at least 2 seasons of use. It is the work of a moment to do it. The F2 Intec front loop fits my UPZ shells beautifully otherwise. The things I've done to try to get the toe pressure evenly spread on my Bomber TD3s is a whole different story. There's a possible product improvement for TDs right there.

Not with a dab from a hot glue gun. Been there.

Your RS binding toe pieces don't seem to have any vertical adjustment, unlike some other F2 bindings. You almost need to tape a 1-2mm thick shim onto the toepiece flat surface bring the underside of the steel loop to bear properly on the top of the boot toe block.

I had wondered about the same and was thinking of mounting mine on the boot shell, or the board surface just outside my front and rear bindings.

Just about to buy my season pass for my chosen field for the coming Southern Hemisphere winter. I'm looking at riding in August.

I was exploring the CARV website a couple of days ago. Was invited to trial run a couple of web pages relating to a new product they are developing. New version is just motion sensors clipped to boot cuffs, no sole pressure sensors, so easily exchangeable between boots. They are now, as well as reporting turn angulation for each leg, reporting G forces experienced in the turn. The higher the G force the more powerful the change in direction, the better the carve effectively. I think there is enough in the graphs the app produces that I can interpret for myself as an alpine boarder to make it worth my while trying it. I'm hoping the new version actually appears in time for me to trial it this Southern winter. Ski IQ is a derived value to stroke the ego. I have more interest in the data. Only one way to find out.

Middle of the board base, finished off with the tail. Soft snow compression on groom and spray creates the width. Absolutely a carve.

Clearly, there are enough rich and foolish people in this world to keep the "luxury" product makers in business.

CARV ski technology has the ability accurately measure changes in ski (boot) sole angle from a zeroed calibration point. In the boots of some skilled hardbooters, it would provide a definitive answer to that question. https://getcarv.com/ And Carv explains why Ted Ligety is so good. https://getcarv.com/blog/why-its-almost-impossible-to-ski-like-ted-ligety Note Ted gets edge angles up closer to 80 degrees in his turns.

@Jack M And there you have it. An example of the significant contribution that the flex radius of a board makes to turn shape independent of SCR. Just come across this very recent and more complete look at ski performance and turn shapes for carved turns. I found it a little more approachable than some other papers, and full of little gems. Amongst the gems, on snow testing with the Norwegian National Ski Team demonstrated that the turn radius with changing ski (board) angle, predicted by the equation behind @NateW's effective SCR calculator, is a reasonably accurate predictor up to about 70 degrees. Balanced carving turns in alpine skiing. Sports Biomechanics, 22 (9). pp. 1209-1242 (Cover date Sept 2023) https://eprints.whiterose.ac.uk/168379/1/carving.pdf

@st_lupo Thanks for the snow penetration by skis reference above. It's photos like those from the topic that in many ways make the most convincing case for board flex being a major determinant for turn shape at high angles. But they also make the case for the calculator producing smaller than actual turn radii at high board angles. take any 12m sidecut and run it through the calculator 45 degrees = 8.5m (rounded) 50 degrees = 7.8 55 degrees = 6.9 60 degrees = 6.0 65 degrees = 5.1 70 degrees = 4.1 75 degrees = 3.1 80 degrees = 2.1 83 degrees = 1.5 85 degrees = 1.1 86 degrees = 0.84 87 degrees = 0.63 88 degrees = 0.42 89 degrees = 0.21 90 degrees = 0 So understand its limitations. Absolutely it calculates the average sidecut. But take the board angle effects with several grains of salt! Note also that the Physics of a carved turn maximum speeds merely note the speed at which snow spray starts to occur, not the point where the snow strength fails and the board slides out from under the rider.

@Hug Masso Try using a computer. When I tried using my phone the layout and text didn't align properly. You enter the measurements (tip width, waist, tail width, effective edge) of your board first. Then it calculates an average sidecut radius with the board flat 0 degrees on a flat surface. Then you can enter different board angles and it calculates the curve as if the board could flex without limit so that the the whole of the steel edge touches the plane supporting the ends of the effective edge.

@Corey Agreed, incredibly complex. Flex radius changes as the board tilts, snow compresses, and the changing bending forces generated by the rider's direction change (both in vertical and horizontal planes). Riders mass and stance width are also variables. The rider's loading doesn't change the board's sidecut, it just changes the board's flex radius. For me, too many people accept the Calculator above as "truth", given that it has the peer reviewed published physics analysis underpinning it, and seem completely unaware of the contribution of the flex curve to final turn shape.

@NateW Just confirmed a suspicion of mine. Enter any SCR then put edge angle to 90 degrees and the calculator returns a turn radius of 0 (zero). The calculator is just returning the curve generated on a perfectly flat surface with nil surface penetration by flexing the board until all of the steel edge touches the surface. Even on ice surface penetration occurs otherwise there is no grip. Ice skates penetrate the ice surface to form a groove the skater is supported by for any change in direction. A calculator for the real world would have some way of calculating the resultant curve formed at the level of the surface by the combination of both sidecut radius and board flex. (Yes, I think that the Physics of a carved turn model is incomplete - https://arxiv.org/pdf/physics/0310086.pdf ) Thinking of it in 3 dimensions - X horizontal, Y vertical, and Z board's direction of travel. X axis represents the sidecut curve Y axis represents the flex curve and the board rotates from X towards Y along its long axis as the edge angle increases. A simple treatment could simulate the boards flex radius at 90 degrees edge angle matching the SCR at 0 degrees edge angle, (assuming also no torsion of the board) and produce a resultant base curve at the level of the surface. If the flex curve radius was able to be varied then we could all see in an accessible way how board flex and SCR interact in forming turn shape. My maths is not up to generating a calculator like this. Nate, how about yours? PS: thinking about it more I suspect that it is probably beyond all but the most expert maths modellers.

@TWM I absolutely agree with you about wider stances and the extra stability and power they bring to riding (up to a point, in my experiments with stance I've found where too long is for me). My point is only about the physical response of the board to mass distribution and gravity in a static measurement. I suspect, but do not have the equipment to show, that the result is similar in a real carved turn in firm snow. The pressure pattern on the board base is much more complex there, compared with the static flex measurement. A thought experiment suggests to me that having a significant length of board beyond the points where the riders mass is attached to the board is essential for the correct flex curve to develop in the board. Having a plate that put the contact points at the ends of the effective edge (the longest possible stance) might even result in a camber type curve in a turn making the board impossible to ride!

Mike's design places the riders mass in the appropriate position for the Stockli carving skis underneath. Specs and images from his website https://www.oneski.com/ describe his plate as 80 cm long and 20cm wide. The distance between the axles is visually clearly less than half the length of the plate, so <40cm, in the same kind of range as a ski boot + binding attachment points. So the question becomes, in comparison with a) a modern freecarve board without a plate and a rider stance of between 50-56cm OR b) a modern racing snowboard with an AllFlex plate with rider mass distributed over 70+cm and enhanced torsion control over that same edge length Which is going to give better carving performance in those 2 comparisons? For me, it's almost a rhetorical question.

@TWM The actual effect is measurable and reproducible. It's not just a "feeling". I did actual measurements with boards and different distributions of the same weight to confirm the result. The length of board between each of the rider contact points AND the outer ends of the effective edge is essentially a lever with the riders mass acting with gravity to produce a bending force. The shorter the lever, the less force to flex the board as a whole.

Just managed to find the answer to my questions. Relatively flexible aluminium section, able to be flexed with bare hands.

Intrigued by the channel. What material is the channel made from? And how much does the channel structure alter the flex in the segment of board each one is in? All the info I've found in a short look has been silent on material and cross section while asserting it allows the board to flex without interference from the bindings.

My memory is they are a 5 mm metric T nut. And replace both nuts and screws with stainless is the way to go. That way if you can't get the metric thread your screw and nut will match. Having had the same corrosion problem and the odd screw fail I now check them before each season starts.

Appreciate your big toes. https://www.theperformancepodiatrist.com.au/our-toeriffic-big-toe/

@kibber Thanks for the UPZ shell comparison at the "same" mondo. I had assumed all UPZs would have the same internal dimensions at the same mondo. Might be worth a question to the new UPZ distributor. The sizing information on the website would suggest all the shells at a particular mondo point are the same size in mm!

And the counterview. I run mondo 29 feet in mondo 29 Intuition Pro Wrap liners in the correct size UPZ shell for mondo 29 feet. I have had the shells stretched to give my big toes more wiggle room. Scrunching the toes up seems counterproductive to me, given that the big toe in particular is an important part of fine balance mechanics. My toes stay warm and comfortable and my toenails don't need to recover after each winter. Getting appropriately moulded instep orthotics then remoulding the liners with the orthotic in situ was a key step in me getting adequate heel hold and being able to set my buckle tension to a sufficient level for control but I don't have to unbuckle for lift rides. I would encourage orthotics rather than boot downsizing.

@ShortcutToMoncton Have you met James? I suspect not. James loves carving, wants to promote carving, and relishes the challenge of carving in soft boots. He is great company to ride with.