What Is Flex Index in Ski Boots?

Skiing is chock-full of terminology, slang and technical jargon. This can be an overwhelming amount of information for those that are not familiar with what all these words and terms mean. One area of terminology with ski boots has to do with the flex index in ski boots. Learn about what the flex index means and how it can help you choose the best ski boot for you.

  1. Flex Index

    • The flex index of a ski boot simply refers to the stiffness of the boot. The higher the flex index, the stiffer the boot. The stiffer the boot means it has more resistance to bending and twisting when undergoing the pressures of skiing. As a general guideline the more advanced skier you are, the stiffer the boot you require, so they can hold up to the demands of your skiing style.

    The Flex Index and Brands

    • It is of importance to realize the number is only useful when comparing among the same brand. Not all brands use the same numerical system. For example Atomic boots may have a flex scale from 1 to 100 whereas Lange boots may only go from 1 to 10. You can still get a sense of what is a stiffer boot in the Atomic lineup versus a stiffer boot in the Lange lineup but just can't compare the numbers directly between brands.

    Benefits of the Flex Index

    • Having a flex index helps with knowing how to get closer to the type of boot for you. With thousands of boots on the market if you know that you are skier who likes, for example, a looser boot, it is much easier to narrow down your search just going off that simple piece of information. If you are shopping in a store, the sales associate will know what boots fit your needs and virtually all online retailers have the flex index listing on the site.

    Drawbacks to the Flex Index

    • The flex index is also criticized on several levels. There is no standardized system for assigning the number to the boot, therefore it is completely subjective to that industry's opinion on what "stiff" or "soft" means. In addition the stiffness of a boot is affected by how tightly the boot is buckled, which is not taken into account when the boot is given the ranking.

    Using the Flex Index

    • Use the flex index as a general number to loosely guide you into the right category of ski boots. The best thing you can ever do to learn about new ski boots is to try them on, talk to experts and, better yet, take them on the hill for a test drive. This will give you the absolute best indication of how well they work for you.