How to choose ski boots

Freeride’s Shopping Guide is expanding and today we are providing useful information which will come in handy when you are shopping for new ski boots.

Have you ever had sore feet from skiing? Numbness? Freezing toes? Most skiers have experienced this at some point and overly tight boots is most likely the cause of it. At the same time, you should not wear too loose fitted boots either. If you cannot move your toes or if the boot is squeezing your foot, this can lead to seriously painful foot problems.

The reason people are buying too big ski boots is that they are making the mistake of trying on ski boots the same way they try on shoes. A bigger size boot may seem more comfortable when you try it on in the shop; however, the big size will make you tighten the boot around your foot too firmly. This will put downward pressure on the arch of the foot and cut off the blood flow, which leads to cramps and cold feet. Instead, if you choose a ski boot that you can just push your foot into, then you only have to close the buckles for the boot to fit firmly. The fit you are looking for is like if you would stand in the empty boot shells and poured plaster into the boot and let it solidify. Quite contrary to shoes, larger size ski boots are NOT more comfortable and definitely NOT warmer.

  • Liner – the soft inner boot, looks like a high boxer boot.
  • Cuff – the top part of the liner.
  • Strap – provides a tight fit between the shin and the cuff.
  • Buckles – tie up the ski boot.
  • Shell – the plastic outer shell of the ski boot.
  • Traction soles – (on the outside of the boot) grippy rubber patches providing better grip on your way to the lift and at the After Ski boot dance.
  • Footbed – lies inside the shell. Made from various materials that provide different qualities.

How do i know that the ski boot is properly fitted?

The boot should feel small, but may not squeeze or put pressure on any particular area of the foot. The toes usually touch the front when standing straight. However, a small space is created as the toes move backward a few millimeters when leaning forward into the skiing position. The heel should be completely fixed. You should not be able to lift the heel when you try to stand on your toes. (This basically requires you to have had a molded insole made)

What boot flex should i have?

All ski boots are marked with a flex rating. Flex in ski boots refers to how difficult it is to flex the boot forward. The rating usually varies from 60 to 110 for ladies, and from 70 to 140 for men. The higher rating, the stiffer boot. The rating is not scientific in any way. Each manufacturer basically has their own methodology to measure flex. One manufacturer’s flex index of 90 may potentially correspond to another manufacturer’s flex of 110. Worth knowing though, is that heavy body weight in combination with advanced skiing ability means you need a stiffer ski boot. The opposite applies for a lightweight beginner. The real issue is in fact how much force we execute when we are skiing. An experienced, skilled and lightweight skier with a non-aggressive skiing style may therefore still choose softer flex.

Skiing style and terrain also play a role in choosing your flex. Jibbing and playful skiing requires a softer ski boot, and high force carving in hard packed slopes requires a rather stiff ski boot, while off-piste skiers usually need medium stiffness in their ski boots.

You will get insufficient support from a boot that is too soft. It will not give you the resistance you need to ski well, as the boot will almost fold over your foot. A more common mistake is to choose a ski boot that is too stiff, especially among men who have a tendency to overrate their own skiing abilities. A boot that is too stiff will not allow you to utilize any flex. The boot will restrain you and prevent you from optimal use of your skis. An overly stiff boot will also force your position too far back on the skis, which will impact your ability to turn and control.

Generally speaking, we shouldn’t get too bogged down in the flex index. After all, flex is only a rough estimate and far from the most important factor to consider. Moreover, it’s close to impossible to test the boot’s flex in a shop An important fact is that plastic goes stiffer in cold temperatures. The boot is exposed to +20°C, or so, in the shop, while it is at least 20-30°C colder in the slopes. Boot material of today has an ability to get exceptionally stiff in the cold weather, thus many people find them “soft as slippers” in the shop. So, don’t try to work out a specific flex index. Instead, decide if you need a soft, medium or stiff ski boot and then have a chat with a ski boot specialist.

Foam injected liner, yes or no?

Heating the ski boot only gives a slight improvement in the fit, similar to what is achieved after using them for a week or two. The improvement is limited and the word “custom molded” in this context is perhaps a truth with modification. To achieve the most accurate fit, you should consider getting customized foam-injected liners. This process involves putting your foot in an “empty” liner and then properly positioning it in a suitable shell. The ski boot is tied up and the liner is then injected with foam through several small hoses. The foam solidifies quickly and you have a perfectly fitted ski boot.

Two- or three-piece shells?

There are two types of shells to choose from today. The three-piece design has been around for a long time, but has now made a real “come back”. The traditional two-piece shell has an upper and a lower cylinder, while the three-piece shell has a base piece, a spine and an interchangeable rubber tongue. There are several advantages with the three-piece shell. It has smoother flex which is suitable for off-piste and park skiing and it provides even support for the shin, which in turn means protecting the shins. As the flex is largely in the tongue-piece, most models allow for easy swap-out of the tongue to adjust stiffness based on your preferences. You shouldn’t immediately assume, however, that a three-piece shell is the right choice. The fit is far more important than the design; hence the fit should be your prime consideration.

What is last width?

Most manufacturers indicate the last width, i.e. the width of the ski boot at its widest point. This roughly indicates if a ski boot will fit a wide or a narrow foot. The width is a good general guideline, but not an absolute measure. It doesn’t indicate instep height, inner volume, heel width, or the width over the toes etc. If you are in doubt as to what last size you need, ask a ski boot specialist in a ski shop.

To achieve the best ski boot performance you also need to consider what you wear in the boot. A thin sock made from Marino wool (at least 50%) is always the best and warmest alternative (a thick sock will not provide more warmth, double socks is simply silly). Marino wool has the pleasant property of not being itchy. Moreover, it doesn’t agree with bacteria and hence you can use your socks over several days without developing a nasty odor.

There are no half sizes in the world of ski boots

It can be difficult to choose the right length, i.e. right size ski boot. Ski boots are measured on a scale called Mondopoint, which is the inner measure of the boot in centimeters, e.g. 25.5, 26.5, 27.5 and so on, and not in traditional shoe sizes such as EUR 41, 42, 43 etc. Something that is unique for ski boots is that it’s not financially viable for most manufacturers to make molds to mass-produce ski boot shells in every half-size. The shell sizes are therefore usually 1 cm shorter or longer than the indicated half size. Adding more material to the liner and hence making the inner measure smaller normally achieves the half-size. This may feel ok in the shop but it will be of no benefit in the long run. The shapeable material of the liner will adjust to your foot after being used for some time. Therefore, be thorough if your foot size is on the border of a certain full-size.

The sole of the ski boot

Good support will prevent the foot from cramping. Running and hiking shoes often have such support built-in. The bottom of your ski boot is completely flat and the outer sole has no specific function. Buying a separate footbed with arch support is an absolute must. Not only will it prevent cramps and make the ski boot warmer, it will also improve the performance of the ski boot as your foot is positioned properly to allow for optimal energy transmission.

In most specialized ski shops it’s standard to sell customized footbeds. A customized footbed will cost you close to a thousand Swedish kronor, but will last you several years. This will likely prevent you from buying customized footbeds for teenagers and younger once, as their feet are changing every year.  A more sensible investment is then a standard footbed, sold by most sports shops. These footbeds provide some extra arch support and can be used in ski boots as well as for a variety of other sporting activities.

What is a booster strap?

A booster strap is an add-on feature you can buy for your ski boots. It is en elastic strap that replaces the existing Velcro strap at the top of the cuff of your ski boot. The idea with the strap is partly the self-locking buckle allowing a very tight fit and partly the elasticity it provides. The effect is a tighter fit and increased energy transmission between the shin and the ski boot plus better-controlled flex. Further, the strap seems to protect the shin and the deep tissue that cover the bones and thus avoiding pain. There are a variety of elastic booster straps available in the market, providing different effects and solutions.

My ski boots are too tight. What should I do?

A well-equipped ski shop has tools to make adjustments to your ski boots. Most of the components in a ski boot are made from plastic, meaning it’s possible to do quite a lot of adjustments. Most ski shops will provide one free-of-charge after-sale adjustment. You should avoid, however, making adjustments during the first 10-14 days of use as the liner of the boot is still modifying to your foot shape – unless, of course, a need for an adjustment is absolutely obvious. An example is if you straight from the start can see that the plastic shell is too small in a specific area.

The best advice when buying ski boots is to buy from a specialized ski shop selling a broad range of boots and with in-depth knowledge in ski boot fitting. Proper fitting always starts with measuring the length and the width of the foot, plus a general assessment of things such as arch, instep, shins etc. There is also a dialog about skiing style and how the boots will be used. This assessment usually leads to excluding a large number of models and leaving 2-3 models that are all most likely highly suitable – and it’s then up to you to decide which model suits your personal preference best.