It's important that you find a ski boot with a suitable flex for you. If your boots too stiff you will be leaning back seat like the terror squad! Too soft and you'll have thighs more jacked than Arnold!
First of all, the flex numbers that can be found printed on the ski boots cannot be compared between different models of boots. For example, you can compare a 90 to 120, but only if they are in the same line of boot. Otherwise, they are meaningless numbers. There are no standardized tests for flex ratings, so regard them as just a guide to select a boot in your ability range.
How do boots flex?
-An overlap boot flexes by moving the top cuff forward towards the lower shell. It can go as forward as there’s clearance for the cuff to move but is also restricted by the rear section of the shell.
-A three piece boot offers flex from its front tongue. With a more limited flex from the rear cuff
The actual amount of flex in your boot will depend on design, the pivot point and density of the plastics used.
What Flex is Right for You?
The best way to judge the flex of a boot when your first standing in them. And that you can flex the cuff of the boot quite freely. (A major thing to note is that the boot will flex differently in colder temperatures, by being a little stiffer.) So what you’re looking for from your boots is to give you perfect amount of travel while your skiing. When you flex your knees forward, they should be able to reach over the top of your toes. Once you reach that far forward, the boot should give you some rebound. It should also feel quite even on your shins as you go forward.
Good skiing is hugely reliant on having the appropriate flex of boot.
This topic can go much deeper and I plan to revisit this subject with greater detail.
For more information on the subject, send me a message :)