Nordic Ski Flex Explained – Ski Stiffness for Classic and Skate Skiing

While choosing the best pair of skis, you should also not forget to consider its ski flex, as it significantly affects your skiing capabilities. Keep on reading below and find out the importance of ski flex and the factors that go into picking the right flex for you.

What is Ski Flex?

Ski flex, also called ski stiffness, is the bend in the shape of cross-country skis needed to cope with the gliding requirements on snowy terrains. Some Nordic skis have a soft flex, while others have a medium to stiff flex. With the proper amount of flex, you can climb, descend, and glide around sharp turns with more power and stability.

How to Know What Flex is Right for You?

The functionality of ski flex varies with its stiffness level and, therefore, affects your skiing capabilities differently. Whether you are a recreational or a competitive skier, you need to keep certain things in mind when selecting skis with the ideal flex.

Generally, a stiff flex prevents the flattening of the ski kick zones, allowing you to glide faster in hard-packed snow conditions. Meanwhile, a softer flex eases foot movement on loosely-packed snow.


Besides snow conditions, the weight and expertise of the skier also need to be considered when choosing the flex. Skiing with soft flex skis is more comfortable for beginners and low-weight individuals.

However, if you are athletic and possess an advanced skill set, you should opt for stiff flex.

Another option is medium flex, which helps you boost the speed while maintaining the utmost balance on hard-packed ice.

You can choose either soft or hard flex skis for classic cross-country skiing by considering the criteria mentioned earlier. But if you are interested in skate skiing, skis with stiff flex will enable you to transfer more power needed to stride laterally.

About Flex Ratings

To simplify the flex selection, ski manufacturers have introduced flex ratings that indicate the level of stiffness of the ski tip and tail.

The flex ratings are usually expressed in kg and should be chosen according to the skier’s weight, skill level, skiing style, and skiing type.

For entry-level classic cross-country skiing, 55% of a skier’s weight will determine the flex value of their skis. Similarly, the flex rating for expert classic skiers is estimated to be 60% of their weight.

Skis with a rating equivalent to 120% and 130% of the skier’s weight will work the best for novice and expert skiers, respectively.

Some skis feature flex ratings expressed as soft, medium, and hard instead of numeric values. A soft flex is suitable for soft snow with bumps, while hard flex glides well over densely-packed snow terrains. Medium flex combines the properties of soft and hard flexes and offers a pleasant skate skiing experience.

How to do a Flex Test?

Although flex ratings help a lot in selecting flex, it’s recommended to go for manual flex tests. A flex test enables you to do real-time testing of the skis to better understand which flex level fits your comfort zone.

As of now, two DIY methods are available for the flex test:

Use a Flex Test Board

This method is highly accurate and involves a test board on which you lay the pair of skis you want to buy. You have to stand on the skis in three positions, and the salesperson will move the slider beneath the skis in each position.

At first, stand with both feet evenly balanced on the respective skis. The slider should move to your feet but not beyond your heel. Then stand on one foot and make sure the slider does not stop before the middle of the foot arch.


After that, shift your entire weight to the ball of one foot and check if the slider passes freely underneath the skis. The slider should not pass beneath the skis at the ideal flex level. If the slider stops past limits, the skis are either too hard or too soft to perform well.

Paper Test

If a test board is not available, you can perform a flex test without external help simply by using a piece of paper. Look for a flat surface and put your skis on it.

Stand on the skis and repeat the same positions for board testing. When passing the paper underneath your skis, use the same criteria as the board test to determine the suitable hardness of the skis.

When determining the flex for skate skis, make sure the paper can pass beneath your foot with minimal restriction in the third position.