Dear fellow skiers :)
Geze SE3: I was a key part of the team that introduced the Geze SE3 ... and I was also, 4-years later, the decision-maker who stopped the SE3 (in fact, the SE3 in Phil's image is mine, on loan to Phil :) ). The SE3 was developed by Dr-Eng Peter Biermann and his team of outstanding German engineers (including Ulrich Kolvatch, Rolf Storandt, Herbert Hasslauffer and others) at the home office in Leonberg, Germany (next to Stüttgart & Zuffenhousen). The SE3 is unquestionably a fantastic example of German engineering in terms of the quality of a manufactured product. I could go on for some time discussing this binding — but I will try to summarize as follows: The SE3 was positioned (from a marketing perspective) for doctors, lawyers and drug dealers ... people who had to be at work Monday morning. Vertical toe release is in response to the BIAD (Boot Induced Anterior Drawer) skiing knee injury-mechanism. BIAD skiing injuries have a prevalence of approx 8% to 15% of all skiing injuries (then and now), though the BIAD injury mechanism is a contributory vector to both the Phantom Foot and the Slip-Catch injury mechanisms, too — thus the term, "BIAD", has a 'relative significance'. The Phantom Foot injury mechanism involves 3 loads, in order of magnitude and direction, as follows: (1) abduction (that's a pure lateral force that enters the medial edge of the ski directly under the projected axis of the tibia, which force acting over the length of the tibia generates a massive valgus torque about the knee); (2) BIAD (pls see above anatomical description); (3) tibia torque ('inward', in orthopaedic terms — or in the natural direction of a DiVinci gear relative to the femur). The BIAD component is 'low"; and tibial torque is almost nil. The Slip-Catch injury mechanism (recently coined by our 'friends' of the FIS :) ) has 'more' of a BIAD-component than in the Phantom Foot mechanism, and still very little tibial torque. BIAD usually contains some abduction (or, alternatively, adduction) and also a small amount of torque about the tibia. When the rear-weighting component of the 3 vectors is predominantly rear-weighting, it's considered 'BIAD', not Phantom Foot, not Slip-Catch. The SE3 absolutely release below the elastic limit of the ACL during BIAD injury mechanisms. However, due to its inherent kinematics, it sometimes also released in response to extreme ski-flex or less extreme amounts of ski flex plus the vector-addition of 'controlled' rear weighting: in other words, it sometimes pre-released during controlled skiing maneuvers that did not induce lads above the elastic limit of the ACL. As one poster recently commented, yes, inadvertent pre-release is far worse than a non-release for skiers who carry speed because K.E. does = mv^2 and when the head or the spine become part of the kinetic impact after pre-release, death or paralysis are Very Real. Death or paralysis is far worse than a broken leg or a sprained or ruptured ligament ... so therefore, we stopped selling the SE3 and issued serious warnings to all former purchasers that this binding was ONLY for 'smooth recreational skiers'. However, not only did the SE3 have independently-adjustable vertical toe release — it was also the 1st binding with forward-twisting 'friction compensation' ('Friction Compensator'). Previous posts indicating that Salomon was 1st with friction compensation are factually incorrect. We diffused the Geze Friction Compensator throughout the line of top-end Geze bindings — except in the metal Geze racing bindings because friction compensator's 'back-off' the toe's release spring proportionally to the normal-force acting on the AFD, and thus, not only is the force of friction 'moderated', but so also is recentering. Thus, friction compensator's have their drawbacks, too — especially pertaining to retention and anti-pre-release. I choose Teflon over compensator's for this reason, though, of course as we all know, Teflon is expensive. But, quoting the great Gilbert Delouche, "Teflon is the only known substance that maintains is low-friction characteristics, even when worn". Geze invested over 11m in the SE3 (that's 11-million US$). Many of the so-called 'binding experts' of that day who are 'smooth recreational skiers' ski on the SE3, today. I have a button that says: "Don't Ask Me About the SE3." ... and sometimes wear it at ISSS conferences. :) :)
There is one person who believes that the incidence of tibia fractures is rising these days "due to the lack of friction compensator's on many bindings of today" (or, that there are far less friction compensator's diffused throughout the total population of today's binding designs). I say, maybe — but, pls: the prevalence of tibia fractures has 'increased' from 2% of all skiing injuries ten years ago to 4% of all, today. In my mind, this is 'statistical noise'. Tibia fractures remain nearly irrelevant due to good toe piece design, though there are no 'evidence-based' studies that correlate, directly, 'good' toe piece designs to tibia fractures. Biomechanical studies do however suggest a plausible link (pls see the peer-reviewed papers by University of Münich Professor, Veit Senner). Besides, that so-called expert also believes release is more important than retention — and he sits in his sailboat in the dead of winter reading books rather than skiing. That person also has not ever measured valgus-torque because he does not want to be 'contaminated by such ideas' — though somehow he has retained control over America's standards that are relegated to the appendix of the minimum international ski-binding standard, ISO 9462. Hmmmm. :) Phil, are you sure he is "probably the leading-expert" ? The 'hole in the envelope' (the valgus torque' that he is not measuring) is what's causing the most prevalent injury in skiing, today. This hole in the envelope that blinds him is the solution — and I feel the same way about the evolutionary-death of friction compensator's. Adaptive radiation certainly has its ways in evolutionary biology.
In summary, during Phantom Foot or Slip-Catch injury mechanisms where the abduction vector that generates Valgus-torque is greater than the pure-BIAD vector and where torque about the tibia is almost nil, lateral heel release has the capacity to mitigate strain across the ACL in a way that voids any possibility of inadvertent pre-release vertically at the toe. Injury mechanisms that are predominantly-BIAD need vertical toe release to resolve strain across the ACL. However, again, only 8% to 15% of all skiing knee injuries are thought to be a result of the predominantly-BIAD mode — and more importantly, from a dirty-finger-nails perspective — when is tibia torque 'pure'? When is forward release 'pure'? Resultant tibia-torque plus bending moment are resolved, practically-speaking, by the toe's AFD (in concert with whichever mechanism, toe or heel, that has the least entropy). Here also, a low-friction boot-binding interface on the heel pad resolves combined abduction forces (converted to valgus torque) and BIAD bending moments — via lateral heel release, though of course, there is always a rise in the peak resultant lateral heel release that's a function of the coefficient of friction of the interface materials on the heel pad and [materials and geometry of the] boot sole. :) Hence, lessons learned from the SE3 seem transferable ... and that is another reason why my button says, "Don't Ask Me About The SE3".
Lastly, any toe that offers vertical toe release in the presence of ACL-injury-producing BIAD loading might consider also aligning its pivot (the pivot that allows vertical toe release) to be placed 'above' the line of action of the vector generated by the incompressability of the boot-sole during ski-flex and by the horizontal component of the vector generated from the ski's tip — in order to decouple innocuous longitudinal shear-loads from the binding's vertical release mode. :) This principle should be / is / transferable to the other modes of release, too.
(( Yes, I worked in a "marketing department 25-years ago" but I was also in my 20's then — and, yes :) I am an engineer, too :) The Germans have no problem with engineers who are also practicing marketing management. ))
Cubco ( poor Mitch & Joe ) and Burt ( poor B.W. & Tippy ) are classic examples of 'forgetting' about the basic principles of functional-decoupling (pls see 'The Principles of Design' by Nam Suh, MIT Press). In both of these designs, lateral toe release is heavily cross-linked to vertical toe release = massive pre-release. These bindings were advertised as "safer", when in fact, they were far less safe because one had to crank-up the release adjustments to attempt to not pre-release, thereby negating the very thing they set-out to do. These designs exhibit classic examples of marketing people playing 'engineer'. :( How dangerous! When velocity is real, pre-release in front of a lift tower or tree is far worse than no-release (obviously — sorry). These designs were so cross-linked (non-decoupled) that it was impossible for just about any skier to stay in them. But they shipped them anyway, without having gone through a process of pre-shipment testing that involved properly informed beta testers, perhaps thinking along the lines of — "when 'cash-flow' variances exceeded budget and when quarterly returns were more important than long-term valued customers, then to heck with testing, let's ship and invoice" Hmmmm ?? Well, they might have met short-term cash-flow — but what about their long-term customers? These guys went out-of-business because their designs were fundamentally flawed. We learned lessons from these examples. Why repeat these same lessons at the expense of those who already knew these lessons? Real product problems must be fully resolved — immediately and decisively — when recognized. Retention (overall retention) must function even with new modes of release (per today's, "standard industry practice") even when the seemingly smallest design changes are made —— and especially when new modes of release rely upon non-standardized boot-interfaces. The SE3 toe decoupled these two release modes (lateral at the toe and vertical at the toe) with its independent mechanisms as does another binding's design concept, in which the other design's toe AND heel NEVER release laterally, together — due to the simple rules of vector-addition — and that is one of several reasons why it does not pre-release inadvertently.
No matter what the design, all alpine ski-bindings must meet the following minimum requirements in order of importance: (1) retention (defined by 'standard industry practice' [sic] — at least ten informed beta testers who are typically large, strong, males who ski the fall line all day every day for at least one month without any 'faults'; if there are 'faults', the design must be re-engineered, new parts must be made / new bindings must be assembled and the full-process must re-start from the beginning with all of the informed beta test skiers: however, no internal-ski-binding-company-on-slope-testing should begin until the design meets the minimum ISO international standards 9462 (release), 9465 (quasi-retention, toe only) and 11087 (~ ski-brakes); (2) comply with minimum international ISO alpine ski-binding standards ISO-9462 (which 9462 includes on-slope testing by independent 'non-ski-binding-company' skiers), ISO-9456, and ISO-11087 (which 11087 also has an independent on-slope-testing protocol) as tested by the [presently] only independent ski-binding testing company in the world, TÜV, of Münich, Germany. It is important to note that TÜV does not write standards — TÜV utilizes the existing minimum international ISO ski-binding standards, plus TÜV certifies the facility where the ski-binding is manufactured in order to attempt to verify that the bindings that are tested at TÜV are 'the same' binding designs that come off of the assembly-line — in order for TÜV to grant "Approval" (pls see the "TÜV-Approved" markings on all bona fide alpine ski-binding boxes). (( Pls notice the difference between #1 and #2: #1 can be accomplished by the binding company's own lab, whereas #2 requires 'independent' verification. :) )); (3) new modes of release / retention that are not standardized according to ISO-9462, ISO-9456, ISO-11087 and by 'standard industry practice' (pls see above ref to 'standard industry practice') should not cause 'side-effects' to what an ordinary binding must do to comply with #1 and #2. All three requirements are upheld in the US by de facto case law; in Germany by statutory law; and in Switzerland they are enforced by the BfÜ.
Epic skiers can verify "TÜV-Approval" of any bona fide alpine ski-binding. TÜV lists on their web site all alpine ski-bindings that have complied with the combination of (a) meeting the minimum international ISO ski-binding standards ISO-9462, ISO-9465, ISO-11078 plus (b) complying with TÜV's requirements for each accompanying ski-binding companies' end-manufacturing facilities (or final assembly / manufacturing-testing subcontractors) to insure that production-bindings are equivalent to the test-specimens.
Epic skiers can purchase the minimum international ISO alpine ski-binding standards, on-line, via ANSI (American National Standards Institute), by referencing the specific standards, ISO 9462, ISO 9465, and ISO 11078. These independent ISO standards (co-developed by the German's via DIN, the American's via ASTM, the French via AFNoR, the Austrians via Ö-Norms, the Swiss via BfÜ, plus other member's national standards organizations — are expensive — but for some of us, they might prove illuminating and even part of our bona fide knowledge base. For others, this information in your hands might prove to be 'interesting'.
Rick Howell :)
Howell Product Development Holding, Inc.