The stiffness or flex of a ski boot refers to the degree of resistance the boot has with the forward movement of the ankle. If you find your flex is so stiff that you can’t even bend your ankle to flex your boot, then it’s time to seek another boot.
My Experience with Stiff Boots
If you’ve ever gotten stuck at the shop when trying on skis or boots because you didn’t know the difference between stiff and soft, you might get a kick out of this story.
I am a petite woman, but I was young and strong when I started downhill skiing. I wanted the stiffest boot I could find because I wanted to stop as quickly as possible. For several years, I skied in one of the stiffest boots around, the World Cup ZA+ 130 from Lange.
I loved how easy it was to stop. There was just a kiss of an edge when I applied pressure on the ski, and sliding to a stop was like getting off a glass-flat bike and rolling to a stop.
I added to my collection over the next several years, and I could easily slide my entire boot collection on top of each other. I must not have realized that they were all stiff.
One day, I found myself getting cramps in my calves after I finished a ski day. I was quite surprised. Shouldn’t a stiff boot keep you from cramping if it blocks all those leg movements?
Why Your Ski Boots Should Be Stiff
Skiing can be a dangerous sport if you don't have the correct equipment – in this case, a ski boot not having the correct stiffness. A boot needs to be adequately stiff to offer support to the skier's foot, ankle, and leg. If a ski boot is too soft, there will be too much bend in the knee, and conequently, it can result in muscle fatigue.
The Difference Between Tight and Stiff
As you get stronger, you will notice you need a stiffer boot, as you need more support. On the other hand, as you become weaker, you will need less support in a boot.
If you find your flex is too soft, it is probably because they are broken in (stiff shells usually require a break-in period) and also due to warming up your foot as you ski.
A stiff boot can result in delayed reaction times and, therefore, can actually be detrimental to your skiing rhythm. A boot that is too stiff can tend to lock you out, making it more difficult to ski.
When you are a beginner, you continually have to adjust your ankle and leg position to maintain the edge angle. This will undoubtedly lead to leg fatigue and cramping in the foot.
How to Tell if Your Ski Boots are Too Stiff
Ski boots must be rigid enough to give the maximum transfer of power but flexible enough to allow you to flex your foot while walking. A good boot should retain its shape after you put pressure on it. If the upper material of your boots is too soft, they’ll have to be replaced.
A stiff boot could result in making you feel like your skis are welded to your feet.
A ski boot that is too stiff will limit the amount of force you can put on your ski. For example, pressing your heel against the back of your boot while skiing will cause you to push your ski tip in a direction you didn’t want it to go, but you can’t stop it.
Doing this repeatedly throughout the day will make skiing exhausting and frustrating and might even cause injury.
A nice way to determine if your boots are too stiff is to relax in them for a few minutes before taking a few strides on the ski.
Then, try to fasten the binding as tightly as you can. If you feel like your leg is pulling sideways when you are trying to tighten the straps, the boot is too stiff for you.
To find out if they’re too stiff, try standing normally with your skis on a hard surface with the bindings set at zero. The boots should hold their form, unlike running shoes. There should be some give, but not enough to bend your foot to resemble a “C” shape.
If you have no trouble flexing your boot just enough to keep your foot in line with your skis, you probably have a properly fitting boot.
Two additional indicators that your ski boots are too tight are pain and form.
Pain
If you don’t have the proper boots, or if they’re too stiff, you will suffer – a lot.
A ski boot that is too stiff will also hurt your knees, ankles, and back.
It will also put huge amounts of pressure on your joints that are not meant to take such force.
This will lead to massive amounts of pain and inflammation and can potentially cause you to give up on the sport forever.
Form
Your skiing style is one of the most important factors to a smooth, pain-free ride down the slope. It can also have the biggest impact on your ability to stay upright and the responsiveness and handling of your skis.
Finding the right stiffness for your ski boots depends a lot on your skiing style. If you’re an extreme skier, you’ll need a more stiff boot than if you’re a blue skier. If you have stiff ski boots, you may find it difficult to turn the skis with your feet. On the other hand, if you have too soft ski boots, you may find it difficult to push yourself forward.
A key part of your skiing style involves two important factors: your flex and how you initiate a turn.
Your main flex is determined by the stiffness of your ski. This is determined by how your ski is designed, built, and used. For example, a high-performance race ski will have a different flex to a recreational ski.
Examining how your skis react in the terrain when turning is the best way to assess how much or how little flex is appropriate for the terrain and conditions you ski in.
How to Adjust the Stiffness of Your Ski Boots
The table below offers a general guideline regarding the level of flex according to your sex and ability level. This flex rating should be indicated on the name of the model of the boot.
Most ski boots are adjustable in order to find the correct stiffness. Many boots come with clear instructions as to how adjustments to the flex can be made.
Read this article for diagrams and a full description of adjusting your ski boots according to sex and ability level.
Final Thoughts
Buying a new pair of ski boots is an investment purchase. You, therefore, don't want to spend a wad of money on boots that do not offer the best support and won't add to your optimal skiing performance. The stiffness or flex of your boot is essential for these two purposes. The stiffness of your boot largely depends on your skiing and ability, weight, skiing style, and sex. Take the time to consider these factors to ensure that your ski boots are stiff – but not too tight and not too soft. This will make skiing a better experience for you all-round.