Editing Ski boot (section)

==Alpine==
[[Image:Ski boots alpin large.jpg|thumb|left|A pair of modern front-entry alpine ski boots made by Salomon. As with almost all modern examples, four buckles are used to close the openings at the top of the foot and front of the leg to produce stiff cylindrical forms. Above the top buckle on the leg is the "power strap", which acts as a fifth buckle. The rivets forming the pivot points that allow the upper and lower portions of the boot to move independently are seen in silver.]]

Modern alpine ski boots have rigid soles and attach to the ski at both toe and heel using a spring-loaded binding. The interface between boot and binding is standardized by [http://www.iso.org/iso/catalogue_detail?csnumber=38623 ISO 5355], which defines the size and shape of the hard plastic flanges on the toe and heel of the boot. Ski boots are sized using the [[ISO 9407|Mondopoint]] system.

===Front-entry===
Front-entry (or "top-entry", rarely "overlap" or "Lange") boots have been the primary boot design for most of the history of downhill skiing. The design evolved from existing leather boot through several steps.

In 1956, the Swiss factory Henke introduced the buckle boot, using over-center levered latches patented by Hans Martin to replace laces.<ref>{{cite web |first=Luzi |last=Hitz |url=http://skiinghistory.org/history/history-swiss-ski-technology-and-instruction |title=History of Swiss Ski Technology |publisher=Skiinghistory.org }}</ref> Laces spread the load across a number of eyelets in the leather, whereas the buckles concentrated the load at only a few points. To spread it back out again, the boots featured C-shaped flaps that stretched over the opening where the laces would be, to the side where the buckles were located. These had the added advantage of also helping block snow from entering the front of the boot.

Beginning around 1960 [[Lange (ski boots)|Bob Lange]] experimented with ways to replace leather with plastic. Early examples used a lace-up design, but in 1964 he combined a new, more flexible [[polyurethane]] plastic with the overlapping flap and buckle system from Henke to produce the first recognizably modern ski boot. Production examples appeared in 1966, and when [[Nancy Greene]] started winning races on them, the plastic boot became a must-have item. Replacing leather with plastic dramatically improved stiffness and control, along with durability and warmth (leather boots had a way of soaking through, which led to wet, frozen feet).<ref>{{cite book|url=https://books.google.com/books?id=YlgEAAAAMBAJ&pg=PA13 |title=Skiing Heritage Journal - Google Books |via=[[Google Books]]|date= September 2001|access-date=2012-08-25|last1=Association |first1=International Skiing History }}</ref> Over time the cuff around the leg evolved upward, starting just over the ankle like leather boots, but rising to a point about halfway to the knee by the 1980s. Only minor changes have occurred to this basic design since then.

Almost all modern front-entry boots consist of two sections, one around the foot, and another around the lower leg. These are joined by rivets/rotating joints near the ankle that allows the leg to pivot forward, but not to the sides. This allows excellent control by transmitting even the smallest lateral movements of the leg to the ski. However, the rigid cuff also makes them very difficult to put on and take off. Additionally, because the boot clamps across the foot, pulling the sides inward, it is difficult to produce a single design that fits a range of foot shapes and sizes. This leads to shell modification services, when the boot is stretched to fit the skier's foot, typically by heating the plastic and pressing it into place. This is also known as "blowing" ("punching", "pushing"). Sometimes material will be ground off the boot to provide more room. This is normally used only with front-entry designs, other designs normally include much more room in the foot area as they do not clamp down the same way.

[[File:Salomon SX92.jpg|thumb|Salomon's SX 92 Equipe was the penultimate development of their SX series of rear-entry ski boots. The boot on the left is in the "open" position.]]

===Rear-entry===
Rear-entry boots were brought to market in the early 1970s by the [[Hanson Industries (ski boots)|Hanson brothers]] to address the issue of getting conventional boots on and off, while also providing a generally better fit.<ref>Seth Masia, [https://books.google.com/books?id=RlgEAAAAMBAJ&pg=PA40 "The Rear-Entry Boot: A Life Cut Short"], Skiing Heritage Journal, June 2007, pp. 40-42</ref> Rear-entry designs were very popular in the 1980s, notably [[Salomon Group|Salomon]] designs like the racing-oriented SX 91 Equipe.

In the rear-entry design, the entire foot area and sole are a single unit similar to a [[slipper]]. The leg cuff is split in two, with front and rear sections that meet at the hinge point at the ankle. The rear half of the cuff can pivot far to the rear, opening wide for easy entry. Closing a cable locks the moving rear portion forward onto the front half, forming the stiff cuff that pivots around rivets at the ankle like a conventional front-entry design. As the toe area is a single piece and lacks buckles for adjustment, rear-entry boots may have considerable "slop", and various systems of cables, plates or foam-filled bladders were used to address this. The upside of this approach is that the foot area can be made larger, fitting almost any foot.

The rear entry design fell from popularity in the 1990s due to their shunning by racers in search of a closer fit. Recent improvements to front-entry and mid-entry boots, primarily in the areas of comfort and ease of entry/exit, have diminished the popularity of rear-entry designs even in recreational roles, though mid-range models remain common as rental boots.

===Three-piece===
Three-piece (or "open-throat") boots were first developed by Mel Dalebout (around 1969), who introduced a rigid magnesium boot shell in that year (Brixia did the same thing with their aluminum shell at around the same time). The big advantage was that the main shell was a single piece that was convex at all points, meaning it could be easily produced using a plug mould. Conventional boots with overlapping flaps required more complex moulding processes. Engineers at Henke, Heierling, Sanmarco and Caber saw the advantage for high-speed moulding, and plastic three-piece boots were on the market by 1972, when Roland Collombin won the Olympic downhill in the Henke Strato.

Boot designer [[Sven Coomer]] later improved the design with a corrugated tongue, and this technique was commercialized by Comfort Products, an Aspen, Colo. company owned by the ex-ski racer Erik Giese. Giese licensed Coomer's concept to the Swiss company Raichle-Molitor; the company introduced it in 1979 as the [[Raichle Flexon|Flexon]], which became very popular among downhill racers and mogul skiers.<ref>{{cite web |url=http://skiinghistory.org/history/origin-three-piece-ski-boot |title=Origin of the Three-piece Boot |publisher=Skiinghistory.org }}</ref> The Flexon was extremely popular among professional skiers, especially for [[mogul skiing|moguls]] and [[freestyle skiing|freestyle]], but a series of business blunders put Raichle out of business in the late 1990s.<ref>Seth Morrison, [https://www.espn.com/action/freeskiing/news/story?id=4589945 "Morrison Hotel: Boots Made for Stalking"], ESPN, 3 November 2009</ref> Several companies produce three-piece designs today, often referred to as "cabrio" boots (after convertible-top cabriolet vehicles<ref>[[Cabriolet (carriage)]]</ref>{{Circular reference|date=December 2015}}), and they are once again becoming popular models.

The design closely resembles a conventional front-entry design, with separate foot and leg sections riveted at the ankle. However, the overlapping flaps of these designs are cut away, leaving a slot-like opening running down the front of the leg and over the foot. A separate plastic tongue is positioned over this opening on the front of the boot, and buckled down to close it. The open cuff (the "throat") makes the boots easy to get on and off, and the shaping of the tongue allows complete control over the forward flex. A single shell can be used with different tongues to provide any needed flex pattern from racing-stiff to freestyle-soft.

===Hybrid leather===
The introduction of plastic boots in the 1960s led a number of companies to introduce "hybrid" boots with plastic inserts for additional lateral strength. These were widespread in the late 1960s, especially from the large collection of Italian bookmakers in Montebelluna, before they started introducing all-plastic designs of their own. Typical designs used a plastic insert wrapping around the heel area and extending up to just below the ankle, allowing the skier to force their foot sideways and offering some edging control. Others, notably 1968's [[Raichle Fibre Jet]], wrapped a soft leather boot in an external fibreglass shell, producing a side-entry design that was not particularly successful.<ref>Greg Morrill, [http://retro-skiing.com/2011/01/raichle-fiber-jets/#comment-3021 "Raichle Fiber Jets"], 20 January 2011</ref> Hybrid designs often incorporated elements of the side-entry or three-piece designs. The Fibre Jet shared much in common with the Rosemount design, for instance.

[[File:Rosemount Ski Boots.jpg|thumb|right|Rosemount's side-entry design, circa 1968. The metal framework that provides forward flex is not visible in these images. The "crushed" section at the top of the boot is an elastic material that prevents snow from entering the cuff.]]

===Side-entry===
Introduced by [[Rosemount Ski Boots|Rosemount]] in 1965, side-entry design consisted of an almost completely enclosed shell with a cut-out section on one side. The cut-out was covered by a flap that hinged along the back of the boot, swinging to the rear to open. Stepping in was very easy, simply sliding the foot sideways in through the opening, then swinging the flap closed and stretching a fabric cover over it to seal it. As the upper and lower sections both opened, metal plates were needed on the sides to connect the two mechanically. A problem was that the boot did not meet perfectly along the join, allowing snow to force its way into the boot, although improvements were continuous. This design fell from use in the 1970s as higher-cuff front-entry boots became largely universal.<ref>Paul Stewart, [https://web.archive.org/web/20121105072353/http://sportsillustrated.cnn.com/vault/article/magazine/MAG1077886/index.htm "A Revolutionary New Ski Boot Has a Streamlined Shell of Rigid Fiber Glass"], ''Sports Illustrated'', 15 November 1965</ref>

===External frames===
The ski boot provides three functions; protecting the foot from the elements, providing a mounting point for the binding, and transmitting forces between the leg and the ski. In theory, there's no reason these have to be combined in a single unit, and several designs have split these functions up. One example is the [[Nava System]] from the 1980s, which used a soft boot that clipped into custom bindings, and an arm that extended up from the rear binding to wrap around the leg and provide lateral control.<ref>Clint Swett, [https://web.archive.org/web/20121104053604/http://sportsillustrated.cnn.com/vault/article/magazine/MAG1065468/index.htm "Have Your Ski Boots Got You Sore? A Comforting Change Is Now Afoot"], ''Sports Illustrated'', 17 November 1986</ref>

===Knee-highs===
In 1980 four designs were introduced that all rose to a point just under the knee. They were normal ski boots below, but used an extended tongue that fastened around the upper leg using a variety of methods. They offered much greater edging control, and were quickly copied by many other companies. They all disappeared by 1983, a victim largely of fashion - ski pants would not fit over them. None are produced today.<ref>Seth Masia, [https://books.google.com/books?id=-JLvKdmbA1AC&pg=PA17 "The Rise and Fall of the Knee-High Boot"], ''Skiing Heritage Journal'', June 2003</ref>


===Rockered Soles===
GripWalk (ISO 23223) is a modification of the traditional flat-bottomed alpine boot with a rockered rubber sole, allowing improved traction and walking ability on slippery or uneven surfaces. As of 2024 GripWalk boots and bindings are widely available. <ref>{{cite web|url=https://www.powder.com/stories/an-explanation-of-boot-and-binding-compatibility|title=An Explanation of Boot and Binding Compatibility|date=12 October 2018}}</ref>