aussieskier Ski Bootfitting Glossary


Ski boot terms can be confusing. With words like Cabrio and Zeppa it's no wonder most skiers leave it up to bootfitters. That's why we've created this glossary to help you understand and get you up to speed with all things ski boots.

Booster Strap

  • An aftermarket power strap which locks using a cam style buckle rather than velcro. It uses elastic over the front of the boot to increase performance and help prevent shin bang.

Boot Board

  • A component of the ski boot that the liner rests on. Either made of softer materials for shock absorption in freeride boots or harder materials for increased performance in performance/race style ski boots. In some ski boots the boot board may be ground down to allow for more overall volume in the boot.

Boot Sole

  • The underneath part of a ski boot that would be in contact with the ground if standing. Some ski boots have replaceable or interchangeable heel and toe sole units.

Buckle Ladder

  • The piece with notches where the buckle wire attaches to close the shell.

Cabrio Design

  • A ski boot that is a combination of three different parts of plastic. The lower around the foot, the cuff which runs up the side and rear part of the leg, and a tongue over the the front of the leg.


  • Altering the angles of the sole of the boot. Canting is a complicated process usually only performed on the ski boots of high level racing skiers.


  • The part of a ski boot that goes up the leg.

Cuff Alignment

  • A feature on the hinge point of the ski boot that allows the angle of the cuff to be adjusted in or out. Usually cheaper boots will not have this feature, whilst high end boots will feature this on hinge points. Some boots may only have one point that is possible to adjusted. Cuff alignment can help bow-legged or knock-kneed skiers regain the feeling of a flat ski base on a smooth surface.

Custom Fit shell

  • Technology from Salomon that allows the plastic ski boot shell to be molded to the skier.

Custom Footbed

  • An arch support custom made to match the skiers foot by a bootfitter to replace the stock sock liner and increase comfort and performance.

Flex Index

  • The rating or stiffness or resistance a manufacturer gives a ski boot. The higher the number, the stiffer the ski boot. However there is no standardised test for flex and as such a 120 flex ski boot may be more stiff or soft than a 120 flex boot from another brand, or sometimes even a different model from the same brand.

Forward Lean

  • The angle that the upper cuff leans forward in relation to the lower part of the shell. A more aggressive (higher number) lean is usually associated with race boots. A more less aggressive lean is associated with a more upright stance.

Flex Adjuster

  • A feature on the spine of some boots that allow the user to increase or decrease the flex index rating to make the boot more stiff or soft.


  • GripWalk (GW) is a similar concept to Walk to Ride (WTR) found in K2, Tecnica, Dalbello, & Nordica boots. Many boots from these brands can have their soles replaced with GW soles for increased grip.

Hike Mode

  • A mode in the boot that unlocks the link between the cuff and the lower part of the shell to allow the cuff to articulate backwards. It can also allow the boot to flex forward easier as well. This makes the boot easier to walk or skin in and is seen in Alpine Touring (AT) or backcountry ski boots as well as some freeride ski boots.


  • The component of the ski boot which allows movement through the ankle joint. There is a hinge point found on the inside and outside of the boot, near the ankle.


  • See liner.

Intuition Liner

  • A fully thermo-moldable aftermarket performance liner that uses EVA foam to increase performance, warmth and comfort.


  • The arched part of the foot between the toes and the ankle, including the top of the foot.


  • Alpine standard norm for ski boots with flat toe and heel soles.


  • Touring standard norm for ski boots with a rockered sole.


  • The internal width of the ski boot measured in mm of the widest part of the boot in the forefoot.


  • The foam structure that sits between the ski boot plastic and the encompasses the foot. The liner provides insulation and comfort. Most liners have some heat moldable foam in them, with the higher quality more expensive liners having a higher proportion of heat moldable foam.

Memory Fit

  • Technology from Atomic that allows the plastic ski boot shell to be molded to the skier.

Micro-Adjust Buckle

  • A buckle that is on a screw thread to shorten or lengthen it’s length. This can tighten or loosen the fit and provides precise adjustment in between the ladder options.


  • The sizing system used for ski boots. Gives the length of a foot in millimetres.


  • The most common design of ski boot. Features the lower part of the shell that houses the foot, and the cuff which overlaps and closes at the front of the leg to provide a secure fit.

Packed Out

  • When the foam liner inside a ski boot compresses. This usually happens over time and can be responsible for the fit of a ski boot feeling loose. Also referred to as 'packing out'.

    Power Strap

    • A velcro strap around the top of the cuff that increases performance, helps to close the shell and secure the fit around the calf and lower limb.

    Prefabricated Insole

    • An arch support made to a predetermined arch shape intended to replace the stock sock liner that comes with the ski boot.

    Rear Entry

    • A style of ski boot where the skier enters the boot through the rear of the shell.

    Reference Size

    • The ski boot size manufacturers base technical information off. 26.5 in mens and 25.5 in womens boots.

    Rockered Sole

    • A curved sole found on Alpine Touring boots. A rockered sole allows for a more natural gait.

    Rubber Sole

    • A ski boot sole with rubber lugs for added traction and grip on hard snow and rocks.

    Rear Spoiler

    • A shim that is placed between the cuff and liner. It can be moved up or down to give more or less support to the calf.

    Shell Expansion

    • The process of expanding a shell using heat and pressure. This is performed by an experienced bootfitter to help match the shape of a shell to the skier and increase comfort.

    Shell Fit

    • A way to assess the size of a ski boot shell.

    Shell Grind

    • The process of grinding away plastic from the inside of the shell. This is performed by an experienced bootfitter to help alleviate pressure in specific areas on the foot.

    Shin Bang

    • A sense of pain and discomfort through the front of the shin. There could be many causes such as ill-fitting boots or packed out liners.

    Side Country

    • Skiing just outside of the resort area boundaries, but still using the resort lifts.

    Sock Liner

    • A thin piece of material underneath the foot between the foot and liner. Main purposes of a sock liner are to cover up the stitching at the bottom of the liner, absorb sweat, and provide a little bit of cushioning.


    • The part of a ski boot that runs down the back of the leg.


    • See flex index.

    Tech Inserts

    • Metal inserts on the ski boot found in the heel and on either side of the toe for use with low tech bindings such as the Marker Kingpin or G3 Ion.

    Three Piece

    • See Cabrio Design


    • An internal measurement of the space available for the skier in the ski boot which may help indicate how it will fit.
    • Volume may also be in reference to the skiers foot. It is measured from one side of the heel, around the instep, to the other side of the heel. As a general rule of thumb if this measurement is higher than the measured length, the foot is considered to be high volume. If this measurement is lower than the measured length, the foot is considered to be low volume. Selecting a corresponding boot based on this is a crucial element to a well fitting comfortable ski boot.

    Walk Mode

    • See hike mode.


    • Walk to Ride (WTR) is found on a handful of boots from Salomon, Atomic, Lange, Rossi & more. Their aim is to combine the best aspects of both types of boots, rockered soles with large rubber tread for grip when walking and the hard smooth plate for interaction with AFD plates of bindings to allow for consistent and reliable release.


    • See boot board

    Zipfit Liner

    • An aftermarket performance liner that is continually molding to the foot. Zipfit liners use granulated cork rather than foams to take the shape of the shell and foot.