Tanglefoot

I can not buy Telemark skis as well. The five members of this household all have cross-country and back-country skis (required for school), alpine ski equipment and a range of snowboards. There is nothing else to do here in the winter, so it is all justifiable, but storage is definitely an issue. Telemark skiing is very popular around here though, by a factor of around 1000 compared to alpine snowboarding. Glad to see others drawing some parallels between these activities - it makes some sense. I still think there is room for improvement in alpine bindings, but as has been pointed out, they need to be simple and robust and easy to understand. I take it I should not order a Teleboard until I understand what the above images are trying to tell me...

Thanks for a lot of great thoughts guys! My original musings stem from boredom during too much air travel this year, and I came up with the list of perceived advantages, which have now partly been debunked. It all hopefully adds to my understanding of the dynamics involved. I find myself flexing my back foot forward quite a lot, even when using heel lift and full forward lean, and I have observed similar behaviour in others on youtube. Also, I have been observing the local Telemark skiers (I live very close to Telemark), and their boot / binding combo allow a lot of fore and aft movement. This movement is mainly through the binding and toe of the boot, and I was trying to draw some analogy to carving a snowboard with steep binding angles. I know that skiing is not the same as snowboarding, but I went along with it for the sake of lateral thinking... Sounds like I just have to bite the bullet and work on my technique. Or should I buy a Teleboard?

I am not blaming gear or making excuses. In every sport, there is continuous technical development, and occasional step changes or breakthroughs. All over the world, there are people working to come up with better solutions, and I can not see anything wrong with that. Boards, bindings and boots are different now to what they were ten or twenty years ago, but you seem to disapprove of this development? As a person with technical interest, I sometimes like to share some thoughts on this forum, as there is usually a lot of constructive feedback to be gained.

I am no hard boot historian, but I am fairly sure that alpine snowboard bindings were originally designed to accommodate ski boots. This was understandable back in the early days of the sport, when many of us actually rode in ski boots - but there are many disadvantages associated with this solution: The sole of the boot is long and narrow, to suit skis rather than snowboards. Hence the lever constraining the boot transversely is very short, and the lever constraining the boot longitudinally is very long. Thus it is hard to control the transverse flex, and there is little longitudinal flex available. Virtually all of the longitudinal flex is handled by the cuff of the boot. Neither my boots, nor my ankles really enjoy going through the range of motion that they are often subjected to. The interface between the boot and the binding are also the walking surfaces of the boot. These are not precision surfaces, and they deteriorate over time. So as a thought for the day, imagine a compact binding that attaches to the middle / sides of the hard boot rather than the ends. This brings the following advantages: The boot could be made shorter. The binding could have a pivot, allowing it to flex fore and aft, maybe offering a significant range of movement. The boot could then be simpler, as the binding would handle more of the longitudinal movement. Less need for complex spring systems in the boot. The interface would be more stable transversely, with potential for harder or softer side flex as required. Elastomeric pads could enable fine tuning of longitudinal and transverse flex, and could be made available in a range of hardnesses and rebound rates. The walking surfaces could be wider, more rubbery and properly grippy, and therefore safer and more comfortable for walking. The interface between binding and boot could be very precise, would not be walked on, and hopefully could incorporate a slick step-in function. I would also like to be able to adjust cant and lift simply by turning knobs while wearing mittens, but maybe I am being greedy now. There are also some obvious obstacles looming: The cost of developing new boots and new bindings at the same time would be considerable. Riders would need to buy new boots and new bindings at the same time. It is difficult to build in flex and adjustability in several directions, without making the binding bulky or high. Or expensive. However, I think such a system, if properly designed, could also work for wider boards and flatter angles, i.e. 99 percent of the snowboard market. This would make the development effort worthwhile financially, if not spiritually. But these wide-board folk would need to accept that buckles make more sense than laces, and I am not sure they are ready yet. Unless we can throw in some pull-on covers that make the boots look like park-ready lace-up soft boots? P.S. I have been on this forum before, so I am well aware that there are genuine hard boot historians out there, who presumably will tell me that this has been tried before, and did not work...

I woke up suddenly, and way too early. After staring at the ceiling for a few minutes, I woke my wife up and explained: "I am a free carving, coffee drinking rocket scientist who rides mainly in Kongsberg. I need more Edge Hold on ice, hard pack and man made snow." My wife, of course, had heard it all before. She just mumbled "Talk to Bruce" and went back to sleep. So I jumped out of bed, downed a couple of swift frappucinos and got to work on my annual "Dear Bruce" letter. Bruce, of course, had heard it all before. He did not hesitate to recommend the "Kongsberg Free Carver 170", which apparently was the blueprint for the Nirvana Energy back in the day. This particular specimen boasts a 20 cm waist, an 11 m VCR, and 0.4 mm Titanal for added Edge Hold on ice, hard pack and man made snow. My wife, of course, was not born yesterday. A few mornings later, she woke me up (suddenly, and way too early), and whispered in my ear: "Mrs. Tanglefoot's board?" So I jumped out of bed, downed a couple of swift frappucinos and got to work on the second "Dear Bruce" letter of the season. Bruce, of course, was not born yesterday. He did not hesitate to recommend the "Steampunk 168", which is based on the "Kongsberg Free Carver 170", but with 0.3 mm Titanal, less whimsical graphics, and a flex pattern tuned to suit the female center of gravity. It later transpired that my wife's actual words had been "Mrs. Tanglefoot's bored", but by then, the "Steampunk 168" was a reality, and the rest, as they say, is history. You don't have to be a rocket scientist to figure it out: Winter is coming.

I am pulling out all the stops this year. Slackline for balance and coordination, cycling for cardio and weight training for strength. I have also got myself a "Carver" longboard with C7 trucks. This thing is fantastic for pumping and carving tight turns, and you can build up speed from standstill purely by pumping. Very different to any other board I have tried - I have been out on it all evening, pumping like a madman. And a new custom build from Bruce is already in the house - this is essential for motivation...

A very valid point, and now that I have had some sleep, I have taken appropriate action. I am finding that it is very difficult to accurately measure a large radius over a short length, but I have made an attempt by checking 300 mm segments at the nose, middle and tail. By converting the height of each segment into a radius, I found that the nose had a 7 m radius, the middle had 11 m and the tail had 9 m. Go figure. With regards to measuring flex, damping and natural frequencies - I think it is reasonable to compare similar boards this way, but it is by no means an industry standard: Place the boards on supports near the tip and tail (same spacing for both boards), put some weights in the middle and measure the deflection. This does not give you the flex pattern, but it gives an idea of the overall stiffness. I have a vibration analysis app on my phone. I leave the boards on the supports as before, and cause the boards to vibrate by rapidly removing the weights. The app then measures the natural frequencies, and gives a good idea of the time it takes for the vibration to die out. Not super-scientific, but quite interesting.

And taper.

I've been losing sleep over this. I have therefore decided on an analytical approach involving an online arc-segment-radius-calculator. According to the initial calcs, an arc segment of width 1500 mm and height 30 mm will have a radius of 9390 mm. This is a close approximation to the Goltes SL sidecut, and the measurements have just come in from the lab to confirm this. By altering the arc height 1 mm, the radius changes only 300 mm. So what's going on? Kessler state a variable radius of 7-11 m for the 156 SL on their website. CLEARLY, the flex pattern has a much greater influence on turn shape than this subtle change in radius along the length of the board. I will be comparing the flex, damping and natural frequencies of the two boards as soon as the bindings are off for the summer.

Clothoid, schmothoid. It's been a busy afternoon at the Tanglefoot Technology Centre. Today' hands-on workshop was held in the Geometry Lab, and the theme was "Sidecuts". Firstly, a 9.5 metre radius was drawn on a piece of cardboard with the aid of a sharp pencil and a long tape measure. The Goltes SL was aligned with the resulting curve, and the match was perfect. The board was then turned 180 degrees, and again the match was perfect. I am not one to jump to conclusions, but this is surely a 9.5 metre single radius board. The Kessler SL was next. On close inspection, there was some local deviation from the curve in places, of around one millimetre. One of the technicians then traced along the edge of the Kessler and turned it 180 degrees for comparison. Now there was a visible discrepancy of around two millimetres, and the evidence was mounting. There is indeed a change in radius along the length of the board, and it appears to increase from a large radius at the tail to a smaller radius at the nose, just like several of you have stated previously. I therefore stand corrected, but I will ask you all to ponder the following: The change in sidecut is extremely small along the length of the board. Surely, the camber profile and the flex pattern of the board will be far more important in determining the turning radius once you are riding hard enough to bend the board more than a few millimetres? Anyone?

Well, I am glad I remembered to write "If I understand the Kessler web site correctly". However, I still feel that the illustrations and explanations on the website are trying to tell me that the sidecut tightens up towards both ends. Must have a read of the patent one evening - maybe after I have traced, overlaid and compared the sidecuts of all my boards.

If I understand the Kessler web site correctly, the sidecut radius is largest in the middle and tightens gradually and equally towards the nose and tail. Combined with a decambered nose and tail, this allows the board to ride a gentler, larger radius turn if desired. The rider input (change of board angle) will also have a greater effect on the turn radius than it will on a single sidecut board. According to a chap I spoke to at Virus, their boards have elliptical sidecuts, which is a very similar idea. I have done some back to back runs with an older, 9.5 m single sidecut Goltes slalom board and the wife's Kessler slalom board this winter, and the difference between the two is shocking. The full camber and single radius of the Goltes means that you absolutely have to keep the speed down and perform turns at the correct radius, otherwise the board starts vibrating and chattering and loses composure. The Kessler is much more versatile, quieter and smoother - it fully forgives you if you overcook it occasionally. Both are metal boards with damping layers, so fairly similar in terms of materials. Now - I have placed one board on top of the other to see how different the sidecuts actually are, and they are identical to within half a millimetre. So it is possible that Goltes have done something more advanced with the sidecut than they have stated on the board. Kessler have patented that shape, after all. Or it is possible that other aspects of the Kessler technology are more important than the sidecut. The decambering of the ends are clearly important, and the materials seem to be very well tuned for the job. Disclaimer: The Goltes is old, and the Kessler is new. This is clearly unfair.

St Lupo, your technique on the hardpack on the black run yesterday morning was nothing short of a step change! Wish I had recorded it so that our friends across the water could see what they have helped you achieve. I need to have a proper read of this thread now, to see if I can improve my own riding to the same extent. On the topic of board choice for steep, narrow and icy: I borrowed my wife's new Kessler Alpine 156 today, and could not stop grinning for the rest of the day. Felt twice as confident as on any other board I have ridden recently - it did anything I asked of it without question, and the grip was fantastic. This particular board is perhaps on the small side for me, but this much I know: I want a Kessler. Note: I am not the local carving guru

St Lupo, I think your fundamental problem was to attempt to snowboard in Telemark. This is a geographical issue rather than a technical one.

If we can provide some light entertainment for Sean - or Bruce - for a few moments, then it has all been worthwhile. Replacing the Titanal with triax fiberglass, while making no other changes to the design, will lead to a significantly heavier board - for the same flexural and torsional stiffness. I think carbon is necessary to replicate the metal behaviour, as well as some analysis, in order to avoid too many prototypes and iterations. Mass is beginning to stand out as a key parameter in these discussions. I am tempted to stick some weights to my old glass Silberpfeil this winter, or to simply bond a sheet of soft, heavy rubber to the top sheet. All in the name of science.

Hello again TLN, I agree that it is an unfair comparison, but the whole reason for this quest is to find measurable differences between metal boards and composite boards. I think I will struggle to get my hands on a composite board that has been engineered to behave like a metal board though. Had to start somewhere, hence the F2 / Kessler comparison.

Sorry - I wasn't being entirely clear... If the aim is to end up with fibres in three directions, there are several ways to combine materials for similar results. The way I had in mind was to use three plies of unidirectional material and lay them up in three different orientations. So unidirectional plies, but triaxial laminate. You can also buy ready-stitched triaxial mats, but you then have fewer to choose from in the marketplace, and less opportunity for fine tuning your laminate. To keep the weight acceptable but keep the torsional stiffness up, I think the diagonal fibres need to be carbon. Woven fabric is difficult to use for these plies, since most fabrics are woven at 0/90, and the rolls are not wide enough to lay the plies at 45 degrees without lap joints. This is probably why manufacturers such as F2 use carbon weave at 0/90 even though this is not a very efficient use of the material. Structurally, three axes should be enough, but I also mentioned the 0/90 weave as a way of making the laminate match the Titanal. The diagonal layers come in addition to the weave, and could then be angled more or less to fine tune the flex and torsional stiffness, or to fit in with the builder's stock materials. Just needs a little analysis...

Hi TLN, The reason for choosing these two boards for comparison is that they are very similar in terms of purpose, rider weight range, length, width, sidecut etc. They are both boardercross type boards, but crucially, the Kessler is a metal board and the F2 is a composite board, so this was my one chance to perform a back-to-back comparison. Unfortunately, the F2 is quite an odd construction in terms of lay-up, which makes it less relevant than if it had been optimised in a similar way to the Kessler. Still - I can only learn from it. Not all experiments lead to great breakthroughs; some seem to be limited to rather incremental gains of knowledge. At least we're having fun...

Hi Mark, First of all, I think "Cadillac ride" is only ever meant as a compliment on this forum. Secondly, it is great to see some alternative ideas being put into practice, and I would love to see a bit more technical detail than is currently on your website. Be sure to protect your trade secrets though... Meanwhile, back in the woods of Buskerud: I have performed some simplified analysis since my last post, and I think that if the aim is to replicate the Titanal layer, the following laminate would work: Two unidirectional layers of standard modulus carbon fibre at +45 / -45 degrees for the torsion, and a layer of 0/90 woven cloth for the bending. This is not the best way to make a lightweight board, but with the correct fibre weights, this laminate will match the torsional stiffness, bending stiffness and mass of the Titanal layer. This can be fine tuned with the aid of any freeware classical laminate analysis program. There has been some really good input on this thread, and I am more convinced than ever that an all-composite board can do the same job as a metal board. However, I am thinking the same as some of the other "posters" here; that the mass is really important, perhaps more so than damping, and that the effect of added mass is often mistaken for damping. This might explain the use of P-tex topsheets. Perhaps the cheapest way to the goal is to engineer a lightweight triaxial laminate with only unidirectional carbon fibres, and then add P-tex or simply a heavy rubber layer to create the desired mass. Mark - I am slightly unsure why you need such a technical core. The shape / thickness distribution is clearly important, but apart from that I though you only needed sufficient shear strength and shear stiffness, since the skins do most of the bending and torsional work? I am fully open to being enlightened on this matter.

BlueB, thanks for your feedback. Everything I have learned in life also points towards the Kessler as the grippier board, but I am not sure which of the measurements show this - if any. I would also love to map some boards that are more relevant to freecarving and to my own weight range, but since I am not measuring to any known standards, I need two very similar boards, made with different materials, for the work to be meaningful. Could this be my excuse to buy another board?

Right then. The lady of the house decided on a trip to IKEA this evening, so I managed to borrow the kitchen scales and both of her boards for long enough to make some useful measurements. I also found a vibration analysis app for my phone, which absolutely made my day, being a nerd and all. So - the wife owns two boardercross type boards; a Kessler Cross 153 and an F2 Eliminator Carbon 153. On first impression, very similar in terms of length, width, sidecut etc. I measured everything that I could sensibly measure, and everything that I thought was relevant for edge hold. Torsional damping and torsional frequencies are highly relevant, but I couldn't figure out a good way of measuring these. This is what I found though, and I am using the Kessler as a base line here: F2 Mass: 13% lighter than Kessler (2862g vs 3286 g) F2 Bending stiffness: 7.3% stiffer than Kessler F2 Torsional stiffness: 24% softer than Kessler F2 Bending frequency: 8.8% higher than Kessler (9.8 Hz vs 9.0 Hz) F2 Bending damping: 33% faster than Kessler (4 s vs 6 s) I don't know what to make of these numbers, but I am confident the edge hold community is here to help. The two big surprises for me were the difference in torsional stiffness, and how much quicker the F2 damped out a similar shock. Another interesting observation is that the carbon Eliminator has a thick, clear topsheet, which is absent on the glass Eliminator. So much for the analysis; the next logical step is to compare the on-slope behaviour. I feel there are two main options: A: I dress up as a welterweight female, and borrow both of the boards for a back-to back test at the first sign of ice on the slopes. B: Sometime in the spring, I ask my wife what she thought of the boards. I'll keep you posted.

Thanks pow4ever - it is beginning to dawn on me that a lot of people are thinking about this already. With regards to Oxess: I am wondering whether the addition of Titanal to a carbon board will mainly add mass, and therefore lower the natural frequencies. This could easily be mistaken for more damping. If there is already carbon in the structure, the carbon will be the stiffest load path, and the Titanal may not do much work. Hard to tell what's doing what though, when different materials are combined in this manner. Interestingly, neither Oxess, Kessler or SG quote the weight of their boards on their web pages. Is this because some of them are surprisingly heavy? On a different note, I've been trying to find suppliers of viscoelastic materials for constrained layer damping, but with limited success - I have mostly come up with self adhesive sheets for acoustic applications. However, I have found one material that is intended for co-curing with composites, and that comes in snowboard-size rolls and two thicknesses. The product is called "Smacwrap Veil ST", it is meant to work well in the snowboarding temperature range, and there is some info on this web site: http://www.smac-sas.com/wp-content/uploads/2014/04/SMACWRAP-VEIL.pdf I have no experience with this product, and I don't know if you could even come close to an answer without building a prototype. 3M also have a range of products, but I am not sure if they can be co-cured, and they seem to be intended for higher temperatures. Quite a bit of technical info here though: http://multimedia.3m.com/mws/media/828134O/3mtm-viscoelastic-damping-polymers-112-130.pdf?fn=Viscoelastic Damping Polymers 11

Shred Gruumer, I don't know what you are taking, but please send some over to Norway so I can try it as well. Now Oxess is an interesting one, I think I have heard mention of their capabilities before. Hard to figure anything out from their website though - they seem to advertise Titanal construction for their high performance boards. Have you been able to compare their carbon boards with their Titanal boards? And just to add another couple of minks to the menagerie: My wife has recently taken delivery of an F2 Eliminator Carbon, which apparently has a "Torsion oriented X45 trial carbon". Upon closer inspection, this is not the case. It seems to have a glass fibre layer next to the core, presumably triaxial, and a woven 0/90 carbon fabric on top of this. This is structural nonsense and seems to be a marketing exercise more than anything else. She also owns a Kessler Cross of the same length, width and intended purpose, so I should be able to carry out a useful comparison here. I just need to wait for her to leave the house before taking the bindings off and performing the structural tests. I also intend to look at the board edges under a microscope to see what is really going on there. I think the Kessler is much heavier than the F2, but again, I need the wife to leave the house so I can borrow the kitchen scales. Wish me luck

It might not qualify as proper exercise, but I love the slackline for improving balance and coordination.

Seems like Rossignol have several patents related to vibration damping, some involving constrained viscoelastic layers. Other manufacturers are also thinking similar thoughts. Try googling "ski damping patent" or "ski damping patent rossignol" if you need some bedtime reading.