Hardness: This is a word which we use in snowboard. Many times, we’d mix flexibility, hardness, strengthness, stiffness with each other and collectively refer to them as "hardness", this is not accurate enough.
This is usually the hardness of the surface, or the hardness of the material itself. Hardness is the ability of the material itself to resist external piercing or cutting, it came from a durometer which is called the Young 's method. Brittleness and hardness are closely linked, usually high hardness also means high brittleness. So the diamond is the hardest natural material yet very brittle, do not take a hammer to smash the diamond. The word hardness would appear in the bottom of the material occasional.
Stiffness: resistance ability to deformation, this is usually measured by cantilever beam or beam. It is also what we usually feeled the "hardness", when we say that a snowboard is "hard", usually we mean that this snowboard is relatively not easy to bend, or bending this snowboard needs more force.
For a single board, stiffness and flex have a certain relationship, but stiffness can not be completely replaced. Hardness may means flexible but also may be of general stiffness.
Sometimes, stiffness and dumpness are related.In racing board sphere, these two will be expressed as the difference between damp board and lively board. But usually, stiffness, hardness can represent the vibration resistance ability of the snowboard. Also, it means that the boards have good anti-shock ability, great hardness and rigidity, the vibration is small which means that the impact of the bumps by the snow would be smaller while the snowboard is working at high speed, it will be more stable.
But if the hardness is too large, the snowboard would be difficult to control. So we need to find a balance point whether it be snowboard, bindings or snow shoes. The more rigid the equipment, the reaction will be more direct, the accuracy higher, the required control capacity is relatively higher, too.
Flex: usually we call it elastic, it can be said as flexible, the ability to restore the status quo after compressed, bent, deformation.
This ability includes the degree and time of restitution. Normally, we say that a snowboard is very flexible, but it is not necessarily "hard", that is to say that this snowboard is good at it’s hardness, but it does not necessarily mean that it is difficult to be deformed and bent.
But in general, if the board is not easy to be bent, then the rebound force will be large, so the rebound time also need to be take into consideration. If this time is very short, and the rebound force is great, it means that the elastic energy is greater. The bending process is the process of energy accumulation, then release the bending deformation, the shorter the release time, the faster the response.
So, in fact,it is a very complex judging process for the manufacturers to mark the value of flex of snowboards. For snowboard, the word flex usually contains two aspects of the content, one is the hardness of the snowboard, one is the snowboard recovery ability. Especially for freestyle snowboards, if the manufacturers directly labeled Flex, then the greater the value, the more bombs of the snowboard , the snowboard more rigid, but the difference between the hardness will not very big.
But if the manufacturer directly marked the stiffness, then the greater the value, the more rigid the snowboard, but the flexibility is not necessarily the strongest.
Of course, the vast majority of manufacturers is completely confused with the word Flex, so the specific flexibility depends on our own experience. But there is a situation that the manufacturer marked siffness in flex, then it means that the hardness and stiffness are of the same thing.